Ok, this is kinda hard to explain, so I will do it the best I can. My wife is the current owner of a 1994 S-10 Blazer Tahoe LT 4x4 4dr. It has the 4.3L Vortec v6.

The transmission, when shifting between 1st and 2nd gear is extremely hard.... it causes the entire vehicle to shake and surge forward. The rest of the gears are nice and smooth. Sometimes, accelerating hard will make it not do it as prominent, or as hard, but if you accelerate slowly, it makes it shift extremely hard. I had a friend look at it, and he thinks that a shift kit has been placed on it, but another friend mentioned something about synchros because its an electronic automatic transmission. The blazer is in great condiditon, and drives well, but this is becoming a very annoying factor for my wife and I and tending to veer away from having it driven alot for fear of it maybe making a problem worse. Are there any ideas about what could be causing this? thanks.

 

How did your friend detemine there was a shift kit installed? Did he drop the tranny pan, remove the valvebody, Check for missing springs and so on?

 

He sat in the back and listened. He is a part time mechanic. He works at LKQ, which is a used parts distributor. Also, underneath the hood, there is a few Moroso parts attached to the engine.... so it has had a few things done to it.

All I know, is it's getting to be really aggravating, and I am worried that it is going to be start of something that's going to require major work.

 

Ok, hmm, do a "search" and see if anyone has had a similiar problem. I bet you'll find some useful information.

I have some tranny mods done but you stated it shifts extremely hard. Then a problem may exist, mine won't break U joints but your problem doesn't sound good. Bump this post in a few days if you don't find any satisfiable results. Good luck!

 

Mine only shifts really hard from 1st to 2nd on days between 43-55 degrees and in town driving. I get a CEL, TPS is the code. Got any codes? Get em checked even if the light hasn't been on.

Otherwise when is the last time the tranny fluid was changed?

 

We just had the fluid topped off, and once we did that, she now shifts harder occaisonally. The check engine light has not been on, but I have a friend who has a scanner, he said he will run it through to see if she is in good order all over.

 

Ok, post up the codes, if any.