New built trans is shifts hard

[rarperformance]

I have a new built motor and transmission. The trans seems to shift when it's suppose to. But when it shifts, it hits hard shifting and also when braking/stopping it hits hard downshifting. How can I fix this?

 

[1KWIKSIX]

What vendors transmission?
NL or Lock up Torque Convertor?
If there is no check ball installed in the input shaft, your shifts will be harsh.

 

[robzombie]

I had the same problem awhile back, and now have it resolved.

Banging on the downshift was really irritating.

Who built it and at what level ?

 

[GNTIM]

They usually shift hard when rebuilt and soften up after a while

 

[larrym]

Converter will play a big part in this.

 

[rarperformance]

A friend of mine who use to work for TCI built it with TCI parts. It was built with a lot of billet parts. It was built to at least handle 750 hp. It a 3600 lock up stall converter with a Contentious valve body.

 

[77 cruiser]

What's that? Contentious valve body

 

[rarperformance]

I got a chance to swap texts with him today. He's currently in Japan working. I asked him about the Contentious valve body. I think he spelled it wrong. He might have meant Continuous valve body from his description on how it works. He says that with the valve body it holds the line pressure at 250 psi all the time. So it will cause a very hard shift. So I guess this is my answer. I will talk more with him when he gets back from Japan. My question is, has anyone heard of this? And why would you do this? for racing purposes?

 

[JimP]

I got a chance to swap texts with him today. He's currently in Japan working. I asked him about the Contentious valve body. I think he spelled it wrong. He might have meant Continuous valve body from his description on how it works. He says that with the valve body it holds the line pressure at 250 psi all the time. So it will cause a very hard shift. So I guess this is my answer. I will talk more with him when he gets back from Japan. My question is, has anyone heard of this? And why would you do this? for racing purposes?

It's a constant pressure valve body, with the higher line pressures you will feel the downshifts and the upshifts will be very firm, it's like that by design but you still need the TV cable hooked up for part throttle shifts. It's done to avoid damaging / burning up clutches due to low line pressures.

 

[Ttype6]

He says that with the valve body it holds the line pressure at 250 psi all the time. So it will cause a very hard shift. So I guess this is my answer. I will talk more with him when he gets back from Japan. My question is, has anyone heard of this? And why would you do this? for racing purposes?

This is your problem. It makes the trans idiot proof as far as TV adjustments to avoid burning clutches. The downside is harsh part throttle shifts. At WOT,the shifts will be exactly the same as the stock set-up. I would never do this to a trans.

 

[85 GN man]

I have a similar issue, I have finally got the car to run pretty good, although when I get on it, it seems to take forever to shift and when it does shift it is very hard, sometimes chirps the tires, but the car will not do a burnout from a standstill.?
when I got the car a few years ago the guy said it had a higher stall converter installed in it, probably for drag racing.
not very comfortable for just cruising around. what should I be looking at a new torque converter or tranny work to get it back near stock