Question:

“MR” wrote: Thanks for the info Ian. Mine does not seem to have the launch shudder as descirbed, but does have a slight clunk like it has slipped and caught just as it starts off. It only does it after it has been on the hwy. and very warm. It has the locking rear end, but don’t know if that has anything to do with it. Any ideas or is that the start of the launch shudder? I have about 15k miles on it now and only use it to tow a travel trailer in season. I guess the only other option would be to try greasing that slip yoke. You could cut off the original style clamp and just use a screw type clamp as a replacement. I’m not sure that greasing this slip yoke will help any, but you never know. Ian

Thanks. I may do that after it warms a little. Been below 0 the last few days. MR

Response:

Thanks for the info Ian. Mine does not seem to have the launch shudder as descirbed, but does have a slight clunk like it has slipped and caught just as it starts off. It only does it after it has been on the hwy. and very warm. It has the locking rear end, but don’t know if that has anything to do with it. Any ideas or is that the start of the launch shudder? I have about 15k miles on it now and only use it to tow a travel trailer in season. Thanks, MR “MR” wrote: Right. This is a two piece drive shaft on 2wd, 02 2500HD. The yoke is covered with the sleeve just behind the support bearing. I looked for a grease fitting, but did not see one or anyway to apply grease without taking the sleeve and drive shaft out. No g-fittings on the u-joints either. Ok, the slip yoke issue doesn’t apply to this truck. There is however a bulletin on “launch shudder” which applies to your truck. Perhaps this is the problem you are experiencing. I’ll quote the bulletin below. Launch Shudder/Vibration on Acceleration (Replace Propeller Shaft and InstallNew Pinion Flange/Seal) #02-04-17-001A – (07/19/2002) Launch Shudder/Vibration on Acceleration (Replace Propeller Shaft and Install New Pinion Flange/Seal) 1999-2003 Chevrolet Silverado 2WD 1500 Series Extended Cab Short Box Pickups 1999-2003 GMC Sierra 2WD 1500 Series Extended Cab Short Box Pickups With 4L60-E Automatic Transmission (RPO M30) Except QUADRASTEERT (RPO NYS) Equipped Vehicles This bulletin is being revised to add Model information. Please discard Corporate Bulletin Number 02-04-17-001 (Section 04 — Driveline Axle). Important Implementation of this Service Bulletin by “GM of Canada” dealers requires prior District Service Manager approval. Condition Some customers may comment on a vibration when accelerating from a stop. This is also known as launch shudder. This condition may occur between 0-40 km/h (0-25 mph) and be more noticeable when the vehicle is carrying cargo or used for towing. Correction A new propeller shaft, P/N 15071486, has been developed to correct this condition. The new propeller shaft incorporates dual double cardan joints on the center and rear joint positions. Refer to Corporate Bulletin Number 02-00-90-002 for lubrication information. The new propeller shaft will require the installation of a new pinion flange kit, P/N 15071485. The pinion flange kit consists of the following components: a.. A pinion flange b.. Hex bolts (four) c.. A pinion seal d.. A rear axle drive pinion nut Replace the propeller shaft with the new propeller shaft using the following procedure. Use the part numbers listed below. 1.. Remove the propeller shaft assembly and the center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI). Important In step 2, you must measure the pinion and differential preload. This information is needed to set the preload of the new pinion flange to the correct specification and to reduce any rear axle noise concerns. 2.. Remove the drive pinion yoke and the pinion oil seal. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI). Important In step 3, use this procedure as a guideline to install the pinion flange to the drive pinion and to set up the proper pinion bearing preload. 3.. Install the new pinion oil seal, the new pinion flange and the new drive pinion nut. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI). 4.. Install the new propeller shaft assembly and the new center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI). Tighten a.. Tighten the propeller shaft flange bolts to 70 N.

Question:

Does anyone know about front end noises? I’ve got a 92 Sierra with the same thing, but it comes from the front drive line. (according to the service bulletin)

Response:

The way the dealer told me, “if you don’t hear any noises, its not defective”

Any mention at all as to how one can determine if the slip yoke is defective if they don’t hear any noises? — www.aadtonline.com Here is a TSB that could be the fix to your problem. There is also another TSB for the same problem that has you change the transfercase fluid to synthetic but I am unable to locate it at this time. Les Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) #01-04-17-004 1999-2002 Chevrolet and GMC Extended Cab Short Box Pickup Models (Silverado and Sierra) with 4L60-E (RPO M30) or 4L80-E (RPO MT1) Automatic Transmission and Automatic 4WD (RPO NP8) Condition Some customers may comment on a clunk, bump or squawk noise when the vehicle comes to a stop or when accelerating from a complete stop. Cause A slip/stick condition between the transfer case output shaft and the drive shaft slip yoke may cause this condition. Correction Replace the rear drive shaft slip yoke with a new nickel plated slip yoke, P/N 12477702 (1500 Series) or 12477704 (2500 Series). Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

Any mention at all as to how one can determine if the slip yoke is defective if they don’t hear any noises? — www.aadtonline.com Here is a TSB that could be the fix to your problem. There is also another TSB for the same problem that has you change the transfercase fluid to synthetic but I am unable to locate it at this time. Les Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) #01-04-17-004 1999-2002 Chevrolet and GMC Extended Cab Short Box Pickup Models (Silverado and Sierra) with 4L60-E (RPO M30) or 4L80-E (RPO MT1) Automatic Transmission and Automatic 4WD (RPO NP8) Condition Some customers may comment on a clunk, bump or squawk noise when the vehicle comes to a stop or when accelerating from a complete stop. Cause A slip/stick condition between the transfer case output shaft and the drive shaft slip yoke may cause this condition. Correction Replace the rear drive shaft slip yoke with a new nickel plated slip yoke, P/N 12477702 (1500 Series) or 12477704 (2500 Series). Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

Regarding the noises in the back end of my 99 Z71 I bought some high heat multipurpose synthetic grease, took out my driveshaft, lubed up the splines on the slip yoke, reinstalled the shaft and ALL of my rear end noises are gone!!! So…..if you get any unexplained noises coming from the rear of your truck upon acceleration from a dead stop, do what I did, it was a cheap fix. if it doesn’t go away permanently, you’ll have to change the slip yoke. Hopefully it’ll stay that way for a while. Brian

Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

Thanks Les!, I’ll look into it, apparently its not something that will break down after so many kilometres but damn!! its an annoying noise, I think I’ll change my transfer case oil to synthetic oil anyway Here is a TSB that could be the fix to your problem. There is also another TSB for the same problem that has you change the transfercase fluid to synthetic but I am unable to locate it at this time. Les Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) #01-04-17-004 1999-2002 Chevrolet and GMC Extended Cab Short Box Pickup Models (Silverado and Sierra) with 4L60-E (RPO M30) or 4L80-E (RPO MT1) Automatic Transmission and Automatic 4WD (RPO NP8) Condition Some customers may comment on a clunk, bump or squawk noise when the vehicle comes to a stop or when accelerating from a complete stop. Cause A slip/stick condition between the transfer case output shaft and the drive shaft slip yoke may cause this condition. Correction Replace the rear drive shaft slip yoke with a new nickel plated slip yoke, P/N 12477702 (1500 Series) or 12477704 (2500 Series). Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

When you say the leaf springs are torquing over, what do you mean? Is the axle wrapping? If so, do you have lift blocks on the rear axle? Has the angle of the drive shaft been changed? I had a locked up u-joint cause the same problem and over time it got worse until I thought the rear end was going to explode. I had just had u-joints installed so I thought, “NO WAY”…but the lazy mechanic failed to do one and that was the culprit. Once in a great while I let someone else work on my truck…and then I am reminded of why I do all my work myself. grin HH

Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

I have the same truck, w 105k on it. I have not noticed any noise from the rear end. I am interested in what comes of yours though in case this is something inherent to the truck. — www.aadtonline.com

Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

Here is a TSB that could be the fix to your problem. There is also another TSB for the same problem that has you change the transfercase fluid to synthetic but I am unable to locate it at this time. Les Clunk, Bump or Squawk when Vehicle Comes to Complete Stop or Accelerating from Complete Stop (Replace Rear Drive Shaft Nickel-Plated Slip Yoke) #01-04-17-004 1999-2002 Chevrolet and GMC Extended Cab Short Box Pickup Models (Silverado and Sierra) with 4L60-E (RPO M30) or 4L80-E (RPO MT1) Automatic Transmission and Automatic 4WD (RPO NP8) Condition Some customers may comment on a clunk, bump or squawk noise when the vehicle comes to a stop or when accelerating from a complete stop. Cause A slip/stick condition between the transfer case output shaft and the drive shaft slip yoke may cause this condition. Correction Replace the rear drive shaft slip yoke with a new nickel plated slip yoke, P/N 12477702 (1500 Series) or 12477704 (2500 Series). Hey everyone! I have a 1999 Z71 extended cab shortbox 4×4, 5.3 litre Have any of you guys experienced noise in the back end of the truck? I went to Chevy and they told me to take the drive shaft out, lube up the Slip yolk with some synthetic grease, that solved allot of my noise but… When I give it gas off the line, it still makes a noise like the rear end is shifting, the leaf springs are torqueing over and making a noise, I squirted some WD40 on the bushings but it only helped a little, the rear diff oil is topped up. I’ve gone to this sight…www.alldata.com it has all the service bulletins available for your vehicle, there are quite a few service bulletins out on my truck with regard to rear end noise but they say it’s normal…typical response form a dealer heh. Any thoughts? Thanks in advance

Response:

Question:

This problem is on what engine?? harryface The Former Fleet ~~~~~>>> 1. 1973 Chevy Impala 4 door,  1980 – 83 2. 1968 Buick  LeSabre Convertible, 1983-86 3. 1978 Olds Holiday 88,  1986 -91 4. 1991 Pontiac Bonneville LE, 1991 to ? ? 5. 1989 Chevy Cavalier Z- 24 Convertible, 1996 to 2000

Response:

It’s at the end of my original post. 5.3

- Hide quoted text — Show quoted text -> This problem is on what engine?? > harryface > The Former Fleet ~~~~~>>> > 1. 1973 Chevy Impala 4 door,  1980 – 83 > 2. 1968 Buick  LeSabre Convertible, 1983-86 > 3. 1978 Olds Holiday 88,  1986 -91 > 4. 1991 Pontiac Bonneville LE, 1991 to ? ? > 5. 1989 Chevy Cavalier Z- 24 Convertible, 1996 to 2000

Response:

- Hide quoted text — Show quoted text – >Thanks Myron and Ian for the replies. >After the carbon is removed from the cyls. is there anything that can be >done to prevent this from happening again or will it need to be done every >30000 miles? > “Dave Brower”  wrote > > I have a couple of problems with this truck. I purchased it new and the > > defrosters have never worked very well. Driving at hwy speeds while it’s > > snowing, the upper three fourths of the windshield will freeze over and > > won’t clear until I slow to residential speeds. Service advisor says > there’s > > nothing wrong with it that he can find. It’s the first vehicle i’ve ever > had > > that could’nt be driven if it was snowing. > Can’t help you with that problem, I’ve never seen or heard of a customer > complaining about that.  Is there lot’s of air coming out at the base of > the windshield?  Have you made sure that you are not using the recirc > button? > > Lifter noise is the other problem. This fall I started hearing them at > cold > > startup. Since it has gotten colder, it’s worse and takes about 30 sec. >to > > go away. Advisor says he called the tech line and they know they have a > > problem, but they aren’t doing anything about it at this time. > I doubt that it’s lifter noise.  We are experiencing lot’s of cold >start-up > noise on these engines, but it has nothing to do with the lifters.  At >this > point it is being treated as a carbon build-up problem and we have > a procedure to remove the carbon in the cylinders.  It involves removing > the spark plugs, installing a chemical in each cylinder and leaving it > overnight. We then crank the engine over to blow out the chemical and > carbon, re-install the spark plugs and change the oil.  The only problem > I have with this repair is that you are not guaranteed to get all the > carbon out of some cylinders as some will be higher in the cylinder > then others and not as much chemical will get into the cylinder. > Apparently, GM is working on a new method of performing this > procedure that includes some sort of specialized tool that ensures > each cylinder is competely filled with the chemical.  We shall see….. > Ian

dont forget about the tsb about some non gm oil filters drianing back causeing a cold start tick Brian

Response:

Thanks Myron and Ian for the replies. After the carbon is removed from the cyls. is there anything that can be done to prevent this from happening again or will it need to be done every 30000 miles?

- Hide quoted text — Show quoted text -> “Dave Brower”  wrote > I have a couple of problems with this truck. I purchased it new and the > defrosters have never worked very well. Driving at hwy speeds while it’s > snowing, the upper three fourths of the windshield will freeze over and > won’t clear until I slow to residential speeds. Service advisor says > there’s > nothing wrong with it that he can find. It’s the first vehicle i’ve ever > had > that could’nt be driven if it was snowing. > Can’t help you with that problem, I’ve never seen or heard of a customer > complaining about that.  Is there lot’s of air coming out at the base of > the windshield?  Have you made sure that you are not using the recirc > button? > Lifter noise is the other problem. This fall I started hearing them at > cold > startup. Since it has gotten colder, it’s worse and takes about 30 sec. to > go away. Advisor says he called the tech line and they know they have a > problem, but they aren’t doing anything about it at this time. > I doubt that it’s lifter noise.  We are experiencing lot’s of cold start-up > noise on these engines, but it has nothing to do with the lifters.  At this > point it is being treated as a carbon build-up problem and we have > a procedure to remove the carbon in the cylinders.  It involves removing > the spark plugs, installing a chemical in each cylinder and leaving it > overnight. We then crank the engine over to blow out the chemical and > carbon, re-install the spark plugs and change the oil.  The only problem > I have with this repair is that you are not guaranteed to get all the > carbon out of some cylinders as some will be higher in the cylinder > then others and not as much chemical will get into the cylinder. > Apparently, GM is working on a new method of performing this > procedure that includes some sort of specialized tool that ensures > each cylinder is competely filled with the chemical.  We shall see….. > Ian

Response:

“Dave Brower”  wrote > I have a couple of problems with this truck. I purchased it new and the > defrosters have never worked very well. Driving at hwy speeds while it’s > snowing, the upper three fourths of the windshield will freeze over and > won’t clear until I slow to residential speeds. Service advisor says there’s > nothing wrong with it that he can find. It’s the first vehicle i’ve ever had > that could’nt be driven if it was snowing.

Can’t help you with that problem, I’ve never seen or heard of a customer complaining about that.  Is there lot’s of air coming out at the base of the windshield?  Have you made sure that you are not using the recirc button? > Lifter noise is the other problem. This fall I started hearing them at cold > startup. Since it has gotten colder, it’s worse and takes about 30 sec. to > go away. Advisor says he called the tech line and they know they have a > problem, but they aren’t doing anything about it at this time.

I doubt that it’s lifter noise.  We are experiencing lot’s of cold start-up noise on these engines, but it has nothing to do with the lifters.  At this point it is being treated as a carbon build-up problem and we have a procedure to remove the carbon in the cylinders.  It involves removing the spark plugs, installing a chemical in each cylinder and leaving it overnight. We then crank the engine over to blow out the chemical and carbon, re-install the spark plugs and change the oil.  The only problem I have with this repair is that you are not guaranteed to get all the carbon out of some cylinders as some will be higher in the cylinder then others and not as much chemical will get into the cylinder. Apparently, GM is working on a new method of performing this procedure that includes some sort of specialized tool that ensures each cylinder is competely filled with the chemical.  We shall see….. Ian

Response:

I think you want to be sure these problems are documented with the dealer. You need the service writer’s comments on paper so you’ll have proof that you called it to the dealer’s attention BEFORE the warranty ran out. Also inquire as to Technical Service Bulletins (TSB’s) on the truck. Myron E. Williams – Hide quoted text — Show quoted text – > I have a couple of problems with this truck. I purchased it new and the > defrosters have never worked very well. Driving at hwy speeds while it’s > snowing, the upper three fourths of the windshield will freeze over and > won’t clear until I slow to residential speeds. Service advisor says there’s > nothing wrong with it that he can find. It’s the first vehicle i’ve ever had > that could’nt be driven if it was snowing. > Lifter noise is the other problem. This fall I started hearing them at cold > startup. Since it has gotten colder, it’s worse and takes about 30 sec. to > go away. Advisor says he called the tech line and they know they have a > problem, but they aren’t doing anything about it at this time. > If anyone has any ideas or suggestions I’d appreciate a reply. 6000 mi. left > on warranty! > Thanks, Dave > 1999 Sierra SLT  Ext cab Z71 5.3 v8 auto

Response:

I have a couple of problems with this truck. I purchased it new and the defrosters have never worked very well. Driving at hwy speeds while it’s snowing, the upper three fourths of the windshield will freeze over and won’t clear until I slow to residential speeds. Service advisor says there’s nothing wrong with it that he can find. It’s the first vehicle i’ve ever had that could’nt be driven if it was snowing. Lifter noise is the other problem. This fall I started hearing them at cold startup. Since it has gotten colder, it’s worse and takes about 30 sec. to go away. Advisor says he called the tech line and they know they have a problem, but they aren’t doing anything about it at this time. If anyone has any ideas or suggestions I’d appreciate a reply. 6000 mi. left on warranty! Thanks, Dave 1999 Sierra SLT  Ext cab Z71 5.3 v8 auto

Response:

Question:

I have 265/70/16’s on mine…I was told I could go to 285’s but it was too expensive.

You can get away with 35’s, but not on stock rims. The IFS components are too close for that. With 35’s you’ll need a “reverse” rim that brings the tire out. They wind up sticking out of the fender well about 3 inches. Without some decent flares it can pummel the sides of your fenders/doors. Keep in mind that most states have “open wheel” laws. Most of the time these laws are not enforced until a trooper pulls you over and he’s having a bad day. In my state it will cost you $25/wheel plus court costs, plus proof of correction (verified by any law enforcement officer).

I had 32’s on an ‘84 Suburban that was stock. but now you have the IFS that may not go past 31’s or 30’s depending on the back spacing of rims. If you are buying new tires many tire shops would be willing to test fit a couple different sizes to check clearance… the bigger the tire the more money they make. Kenny I have a 1990 GMC Sierra-SL 1500 4×4 (K-1500) pickup truck. Does anyone know what is the LARGEST size tire that I can put on it without rubbing the fenders? The truck is stock, no lift. Thanks, Tony Kimmell Normal, IL “Injection is nice, but I’d rather be BLOWN” 86 Chevy C-10 68 Chevy C-20 79 Ford F-250 Before you buy.

Response:

You can get away with 35’s, but not on stock rims. The IFS components are too close for that. With 35’s you’ll need a “reverse” rim that brings the tire out. They wind up sticking out of the fender well about 3 inches. Without some decent flares it can pummel the sides of your fenders/doors. Keep in mind that most states have “open wheel” laws. Most of the time these laws are not enforced until a trooper pulls you over and he’s having a bad day. In my state it will cost you $25/wheel plus court costs, plus proof of correction (verified by any law enforcement officer). I had 32’s on an ‘84 Suburban that was stock. but now you have the IFS that may not go past 31’s or 30’s depending on the back spacing of rims. If you are buying new tires many tire shops would be willing to test fit a couple different sizes to check clearance… the bigger the tire the more money they make. Kenny I have a 1990 GMC Sierra-SL 1500 4×4 (K-1500) pickup truck. Does anyone know what is the LARGEST size tire that I can put on it without rubbing the fenders? The truck is stock, no lift. Thanks, Tony Kimmell Normal, IL “Injection is nice, but I’d rather be BLOWN” 86 Chevy C-10 68 Chevy C-20 79 Ford F-250 Before you buy.

Response:

I had 32’s on an ‘84 Suburban that was stock. but now you have the IFS that may not go past 31’s or 30’s depending on the back spacing of rims. If you are buying new tires many tire shops would be willing to test fit a couple different sizes to check clearance… the bigger the tire the more money they make. Kenny I have a 1990 GMC Sierra-SL 1500 4×4 (K-1500) pickup truck. Does anyone know what is the LARGEST size tire that I can put on it without rubbing the fenders? The truck is stock, no lift. Thanks, Tony Kimmell Normal, IL “Injection is nice, but I’d rather be BLOWN” 86 Chevy C-10 68 Chevy C-20 79 Ford F-250.

Before you buy.

Response:

I have a 1990 GMC Sierra-SL 1500 4×4 (K-1500) pickup truck. Does anyone know what is the LARGEST size tire that I can put on it without rubbing the fenders? The truck is stock, no lift. Thanks, Tony Kimmell Normal, IL “Injection is nice, but I’d rather be BLOWN” 86 Chevy C-10 68 Chevy C-20 79 Ford F-250.

Response: