I was just wondering how bad is it to manually shift an automatic transmission from 1, 2, D, to OD ? Is it so bad that I should never do it or is it okay to do it every now and then? What would happen to my tranny if I did it all the time?

 

well i personally do it all the time. just go easy on gearing down.

 

I manualy shift my car all the time.It has broke yet.

 

I would not do it unless you have a manual valve body.I speak frome experience that you will damage your tranny eventually

 

Shifting into neutral even when letting off the throttle could cause more damage than manually shifting through the gears.

 

With the 1988 unit you have the .282 intermediate/reverse boost valve, which is the 2nd largest GM has to offer. If you are manually upshifting this boost valve comes into play in 1st & 2nd gear (raises line pressure). The shifts should/will be firmer than if you left in drive (D) position. Once into 3rd the transmission relies on the main boost valve, in your case a .421 (OK, but could be better, .471, .500, maybe?) If you were to install the Trans-Go Performance Shift kit, .471 or .500 main boost valve, along with the GM .296 int/rev boost valve and the Corvette servo (with some slight modifications), you would have the best chance on this unit staying alive for awhile. If you down shift this unit then the above is absolutely mandatory. When downshifting make sure you are giving it throttle to make sure the line pressure is up, and that the engine rpm's & trans rpm's match each other quickly. When this unit quits and it is time for the rebuild. install the springs that were in the Shift kit that could not be installed at the time of the Shift kit install. There are a lot of other things that can be done to insure longevity on the rebuild, we can address those fixes at that time.