I have a 91 Camaro Z28 with a 305 and a 700R4.
It upshifts great using the shifter or if placed in overdrive and left there.
The problem is, if I try to manually downshift it from a higher gear to a lower gear it will not pull in the lower gear unless I get the RPMs up.

I guess that I am saying I can downshift and the car does not slow down. It is like I shifted into neutral instead of a lower gear.

I checked the fluid and the level is past full, which I know that is was not before. The fluid does not smell burnt and the color looks like it did the day I changed it.

Please only give me your opinion if you know what you are talking about.
Thanks to all!!

 

????

 

you might be losing pressure in your pump do to manually downshifting an automatic transmission.

 

I have read many posts andmany cars have had the same symptoms as mine. It seems liek everyone points toward the overrun assembly. I do downshift the car manually quiet a bit, but never to the point of breakage (or at least I thought). Either way, I am taking the tranny out and having it rebuilt.
I will try to post the results of the rebuild and what happened for anyone having the same problems in the future.

 

Just have a manual valve body installed while its out and problem solved