97 Jimmy Transmission

[mjtr21]

Hello I have a 1997 Jimmy 4.3 V6. I have been curious for the past couple of years and I have a problem thats been buggin me since I got my transmission rebuilt. I had it rebuilt in 2000 and it had about 120,000 miles on it. When it was first done the guy said it may shift kinda hard but it will go away. Well it did but not for all the shifts. Ever since I had it rebuilt it has always jerked between 1st and 2nd when it shifts. Its nothing major not like slipping but its not as smooth as other blazers/jimmys I've ridden in. So how would I get this fixed? My uncle suggested getting the bands redone or something like that but I can't remember. What are your peoples' thoughts on the matter. I would like the transmission to shift a bit smoother. It shifts very smooth in other gears but its just the 1-2 shift where its kinda jerky. Please and Thanks.

[RexNfx400]

Sounds like there is a calibration error the rebuilder built into the transmission. There are sooo many different reasons for this. Computer logic, 1-2 accumalator problem, side servo problem. Mix match of parts like valvebody/separator plate, oversized boost valve, Vette servo piston, shift kits, not clearing computer adapts. Some guys will put in "bigger parts". Sure this can make the transmission last long and such. But creates driveabilty concerns such as yours. All shifts should have the same "shift feel" while making a ratio change at same engine load. So to speak

It would be hard to tell the exact discription of your 1-2 shift feel without driving it. To see if its from an over zelous "bigger is better" builder to maybe a loose band adjustment(which is not adjustable, say, like a C6) where you actually get a sliding shift with a "bang" at the end of it. Some guys like to plug, drill, resize, redirect certain ports in the hydraulics and such too. To make it "heavy duty" or correct "engineering oversights" This is fine, when done correctly and balance of hydraulics is understood.

Your transmission guy should have corrected your complaint with the 1-2 shift feel long time ago.

[mjtr21]

well that must be my problem then is that he used bigger parts because he thought they would last longer. no, my shift is not that sliding then BOOM kind. when mine does it its enough to move your head forward when it shifts though. but no signs of trouble or anything bad. its just annoying because the other gears switch smoother. so what youre saying is that its not fixable unless i get it rebuilt again? thanks.

[donwkk]

Originally Posted by mjtr21

well that must be my problem then is that he used bigger parts because he thought they would last longer. no, my shift is not that sliding then BOOM kind. when mine does it its enough to move your head forward when it shifts though. but no signs of trouble or anything bad. its just annoying because the other gears switch smoother. so what youre saying is that its not fixable unless i get it rebuilt again? thanks.

You don't need to get it rebuilt again but you need to get the calibration error fixed. Most of the parts that control calibration can be reached and changed with the trans in the vehicle.

You would need a trans tech with:
A.The know how to tackle trying to correct someone else's error.
B. Willing to take the time for what might become a trial and error process.

Time is money. The problem may be that you will want the tech to tell you how much time and how much money it might take to fix the problem. It will not be that easy. A good (and lucky) tech might get it with one try but it could easily take 2 or 3 or more tries. If each try involves putting the truck on the lift, draining the fluid, dropping the pan and filter, making changes, putting everything back together, lowering the vehicle , test driving and maybe luck or no luck, you can see how time and money could pile up.

The shop that rebuilt your trans test drove it and knew they screwed up. Rather than spend the time and money to correct it right then and there they gave you the truck with the BS that it will be OK in time.