1G Auto being rebuilt to shift kit or not

[enriquez2000]

My trans took a dump and my local performance trans guy is rebuilding it for me. I asked about a shift kit and he says he doesnt like using them but didnt want to go into detail.

This car is a daily driver so im not sure super firm shifts would be a good idea but i wanted opinions on this while the trans is out.

Would i be better just using a shift box for the occassional fun pull and forget about shift kit?

 

[CrackedDSM]

Why exactly does he not like using them? That would immediately make me doubt the builder. Shift kits on these transmissions do nothing but extend the life of the clutches and the transmission itself. You can adjust active and reducing pressures to make the shifts a little more tolerable if you're worried about super firm shifts, but honestly it's not that bad. I like the feeling of it shifting firm and to the point. It especially helps if you ever go with an aftermarket restalled TC to help prevent the flare up between shifts.

I'd honestly worry this dude even knows how to properly install a shift kit, must less adjust all the pressures and settings to dial it in like a professional would know how to do.

 

[enriquez2000]

Why exactly does he not like using them? That would immediately make me doubt the builder. Shift kits on these transmissions do nothing but extend the life of the clutches and the transmission itself. You can adjust active and reducing pressures to make the shifts a little more tolerable if you're worried about super firm shifts, but honestly it's not that bad. I like the feeling of it shifting firm and to the point. It especially helps if you ever go with an aftermarket restalled TC to help prevent the flare up between shifts.

I'd honestly worry this dude even knows how to properly install a shift kit, must less adjust all the pressures and settings to dial it in like a professional would know how to do.

Well he has built most of the performance trans in the area including matt frosts 2500hp noba and the 31... i trust him completely.

He said something about it causing premature wear and wouldnt recommend it except for track use.

He will do it if i ask... maybe i just have him use the lesser spring.

 

[CrackedDSM]

There's a difference between rebuilding a powerglide and rebuilding our W4A33. Domestic autos, especially the TH350/400s and Glides are a different breed than the W4A33. It's like our cylinder heads VS a 350's head. What'll work perfectly on a 2500hp V8 won't work worth a crap on a 4G head.


With that said, force him to do the shift kit and ignore what he says. Make sure he gives you a list of what pressures he has adjusted and how, and make sure he doesn't just install it straight up and not adjust anything.

 

[motomattx]

Well he has built most of the performance trans in the area including matt frosts 2500hp noba and the 31... i trust him completely.

He said something about it causing premature wear and wouldnt recommend it except for track use.

He will do it if i ask... maybe i just have him use the lesser spring.

Shift kits are HARD on the transmissions hard parts, while it can extend the life of the clutches it comes at the price of increased wear on the other parts, there are plenty of reasons not to use them from a transmission techs point of view, do your research and decide if its right for you or not.

 

[enriquez2000]

I think that is what he was getting at and recommended if im daily driving to not do it... i put 300miles a week on the car.

If i did a shift box i could use it when i want to have a bit of fun versus permanent.

I also have a tcu thats chipped where i could have shift points and firmness written into the code in power mode.

A shift kit would be a permanent modification versus one of the other options.

 

[motomattx]

He is right and Im sure that is what he was getting at, as you said toggle switch shifting of it can be removed or not used at any time.