Hi everyone!
My 88 iroc 350 tpi has started shifting badly.. here are the syntoms:
- 1st to 2nd 99% of the times regular
- 2nd to 3rd at minimum or light throttle no problem but from 2000rpm and up shifting takes more time then usual with loss of torque in the meantime
- 3rd to 4th same as above but less noticeable.
- Sometimes it slips
- at WOT sometimes hunts, some times slips.

I've already done:
- new trans fluid and filter (the old fluid was clean with no sign of clutch wearing)
- new governor
- cleaned the valve body

What can it be? Do you have any suggestions?

Thank you

 

It could just be time to refresh your transmission. Your car is 26 years old. If it has a lot of heavy use miles on it, it could just need new frictions installed to cut down on the slipping. You really won't see chunks of friction plates unless something really bad happens. I have seen 3-4 friction plates that have the center teeth worn completely off. Usually, it's the plates in the center of the 3-4 group, this could cause a slip and maybe cause a delayed shift feel.

The 3-4 frictions are usually the first ones that you may feel slipping, at least in my experience. These issues will get more noticable as time goes on. Now would be a good time to think about a rebuild and improve some things along the way.

You could fix some drainback issues in the pump that may need to be taken care of as well as add a boost valve, a Corvette servo, and some better friction material.

You could even put in a shift improvement kit and should have a solid transmission that will last you several more years.

 

Wait! Maybe I've fixed it!!
Yesterday I was looking at the engine bay and noticed that the TV cable was a bit loose.. so I set it a little bit tighter (2-3 mm shorter).
Now it shifts perfectly, very quick and smooth!

Thank you StealthESW for your suggestions, I'll remind them when will be time to rebuilt!

 

Proper TV cable adjustment is critical to the 700R4/4L60 transmissions. I hope that adjustment is correct. If you need to check the cable adjustment checkout this thread by another member.

https://www.thirdgen.org/forums/tran...djustment.html

 

Thanks for the good link!
The car is still runnig very fine so I keep on like this by now!