Maybe I am just expecting too much, but I have two problems with when my transmission is shifting, and I don't know if it's operating as intended, or if there is a problem with my car, or if there is an adjustment I could perform. Some history on the engine, it's a 1990 Coupe, and I rebuilt the engine using the block and rotating assembly from a crate engine that came out of a wrecked car. I use my stock heads and intake, but I did upgrade the lifters and the cam to a ZZ9. So it's basically a totally stock engine except for the cam and lifters.

1. When I have it floored, in 1st gear it will rev up to about 6k+, and then I could feel the car stop accelerating, and yet it is still red-lined for a second before it finally decides to shift.

2. When stopped at an intersection and making a left turn, when I take off I will give the gas a relatively health push, but not too much, and of course then the car will shift from 1st to 2nd halfway through my turn causing my back tires to lose traction and then my rear end will slide sideways a little.


With problem number 1, I have found that if I watch my RPM I could just let off the gas a bit which will cause it to shift if I have it floored.

Problem number 2 is the most irritating. I have to give it enough gas so that it won't shift halfway through my turn, which means showing everyone in the intersection what "cornering" ability is, or I have to accelerate at the same speed as the soccer mom in the mini-van next to me.

I don't think I have any vacuum leaks which I think could cause delayed shifting, but I am planning on replacing all vacuum lines soon just in case.

Is there some way I could electronically make my tranny shift, or is it purely mechanical/vacuum controlled?

 

have you done the 700R4 Throttle Valve (TV) Cable Adjustment?

 

Problem number 2 is most likely easy...you need new tires

Problem number 1 reminds me of a problem I had with my 1989, the problem I had was a race between the rev limiter and the 1-2 upshift point.

The factory setup had the WOT 1-2 upshift point and the rev limiter set very close, something like the rev limiter was set only 50 or so rpm above the WOT shift point...

So often the car would rev to "red line" and just hang there for a second or so before it would finally shift.....a race between the rev limiter and the upshift

Not sure how this relates to your problem as the factory shift point was not 6K+ as is yours, but your symptoms sound very similiar to what I experienced.

Upping your rev limit a little more might me an alternative solution. A shift point above 6k+ is certainly not the factory setting for an L98 engine, so assume this has been modded.

Good luck!!!

 

In wet weather my Vette would break loose if I even thought about touching the gas pedal---and I had a surprise or two in dry weather too----'til I replaced the tires. I haven't broken loose yet with the new ones, but haven't pushed it too hard yet either.

 

Make sure your tv cable is adjusted properly. If the shifts are still at too high of an rpm, get a B&M governer kit and use heavier weights or add solder to your existing weights. That will lower the wot shift points. You need to soflen up the 1-2 shift if the thing chirps at part throttle. Use a softer accumulator spring or take the shims out. Willie