125C/3t40 tranmission down shift help

Nov 15, 2005 3 Replies

I have a 1991 Oldsmobile Cutlass Ciera(with 85k) when going from 3rd to 2nd it will make a "clunk" Not so much that it jerks the car around but you can feel it a little and hear it. It happens at 20mph every time. All other shifting is perfect or i think it's perfect as it took me couple times to even count how many speeds it had. quiet and soft. I guess it could be a little harder but seams good. transmission oil is red and seams good. I just got the car so i don't know when or how this started.



Searching the net only thing i could find with the same problems was

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he had the same problem with a 87 Calis but at 15mph it was broken servo spring. I was going to give it a looking at this weekend.



But i was hoping if anyone else had any ideas that i can look for?



Make sure that the motor supports, and braces are in good shape. If they are loose, then a simple downshift can sometimes feel and sound pretty bad.

A sticking valve body can make transmissions do crazy things, as can a balky lockup convertor.

Thanks for the idea i will unplug the lockup and see if anything changes. I will also check the supports again, I only give the a basic visual check.

Thank you :)

Very welcome. You might try rocking the engine against the supports. Some of those things, dogbones especially, may look okay but be too loose.

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