My 1987/93 GMC Jimmy.
Question:
I own a 1987 GMC S15 Jimmy Sierra Classic. When I got it, it had a 2.8L V6 on it w/ TBI. I replaced that with a 4.3L V6 w/ an Edelbrock 500 4-barrel carb. Here’s my problem. When the trans is in Drive and you ‘kick it’ so to speak and open up the 4-barrel, the transmission wants to change gears…and change…and change…and change…constantly.. It never settles into a gear. Is this a problem with the fact that I have no computer hooked up or do I have other trans problems ( Trans is also off of a 1993 S10..same vehicle as the motor )? The one other ‘interesting’ thing about this trans is that when you slow to a stop it ‘thuds’ when it downshifts to first gear. The trans that was with the 2.8 did the same thing. That must be a characteristic of those transmissions. Now, obviously their is no harm in it wanting to swap gears all the time, but it annoys me. And decreases acceleration..a lot. I have considered just swapping transmissions, and putting in a 5-speed manual trans. I prefer a 5 speed anyhow. Im not sure how hard the swap from auto to 5 spd would be. Anyone ever tried this? That I KNOW would fix the problem. My other question is… what is the electrical plug that is plugged into the transmission? I dont really know what electrical goes to the trans.. but if it went to the computer, its not working now. That could be the source of the problem. Anyone have any insights? Jeff
Response:
I own a 1987 GMC S15 Jimmy Sierra Classic. When I got it, it had a 2.8L V6 in it w/ TBI. I replaced that with a 4.3L V6 w/ an Edelbrock 500 4-barrel carb. Here’s my problem. When the trans is in Drive and you ‘kick it’ so to speak and open up the 4-barrel, the transmission wants to change gears…and change…and change…and change… constantly.. It never settles into a gear. Is this a problem with the fact that I have no computer hooked up or do I have other trans problems ( Trans is also off of a 1993 S10..same vehicle as the motor )? The one other ‘interesting’ thing about this trans is that when you slow to a stop it ‘thuds’ when it downshifts to first gear. The trans that was with the 2.8 did the same thing. That must be a characteristic of those transmissions. Now, obviously their is no harm in it wanting to swap gears all the time, but it annoys me. And decreases acceleration..a lot. I have considered just swapping transmissions, and putting in a 5-speed manual trans. I prefer a 5 speed anyhow. Im not sure how hard the swap from auto to 5 spd would be. Anyone ever tried this? That I KNOW would fix the problem. My other question is… what is the electrical plug that is plugged into the transmission? I dont really know what electrical goes to the trans.. but if it went to the computer, its not working now. That could be the source of the problem. Anyone have any insights? Jeff ** I attempted to post this message once from my ISP’s news server. Alas, it never showed up. So its possible in a few days this message will show up again… knowing my ISP, its doubtful. Share what you know. Learn what you don’t.
