trans short shifting

[don86T]

My transmission shifts ok from 1st to second but then almost immediately into third. This is only at part throttle. WOT shifts are fine. I have been putting up with this for a while. Lately I have spending more time on the street than at the track so it's getting annoying.

I have readjusted the TV cable and tried a couple clicks tighter, but that didn't seem to help.

Any suggestions?

Don

 

[chris718]

we need pressure readings and wot shift points in engine rpm.do you get a 2/1 kickdown in manual second @15 mph at wot?

 

[don86T]

Finally found some time to spend on the car.

WOT Shift point: 4900-5000
Downshift from 15 MPH in second yes, but not at 18 MPH
Pressures:
Min TV- P/N 85, Rev.135, D/OD 85, 1st/2nd 250
Max TV- P/N 230, Rev.300, D/OD 230, 1st/2nd 250

Thes pressures were with engine at operating temps but trans just warm to touch. The trans seems to shift the same cold or hot though.

Thanks for looking and input
Don

 

[77 cruiser]

How long has it been doing this?
Was the trans recently rebuit?
Press. look good.

 

[don86T]

It has been since I installed this transmission. The trans was purchased used, from a low mile gn. I just installed a shift kit used and my old converter (2800 D5).

Like I said, I had not put many street miles on it so I didn't worry about it. When I started using it on the street is when I became concerned.

My main concern is with it shifting that way is it damaging the direct clutches?

Don

 

[77 cruiser]

Did you change any springs in the VB?
Like the MTV upshift spring, a GN VB doesn't have one. If you did that could be the problem.

 

[OneLethal87GN]

It sounds as if you have the same problem I had after my rebuild. The mechanic called it a "stacked shift". He said it was caused by something in the valve body. He tried cleaning the valves out and it helped alot but the stacked shift would still come back every so often. He put in a new valve body and all was well....almost. If you try replacing your valve body make sure to use a GN body. He used a non-performance valve body in mine and the shifts are alot softer, even with a shift kit and 200 servo.

 

[don86T]

The only valve body springs I changed were the accumulator valve assembly spring, the line bias valve spring and the 1-2 accumulator spring.

I don't know about the TV modulator upshift spring. It is a gn valve body though.

Stacked shift sounds like the proper term. Maybe it is just dirt or lint in the valve body somewhere.

Thanks for the input.
Don

 

[chris718]

if the wot are where you say they are they are good.if you want a later 2/3 at part throttle we do sell a spring.first see if yours is broken though

 

[Lee Thompson]

spring

Chris, what spring are you talking about. 2-3 shift spring?
THe trans that is in my car now does exactly the same thing (wot shifts are @ 5400 but part throttle it goes into third right after the 1-2 shift).
I tried a stiffer 2-3 spring but no change.

 

[don86T]

Thanks for everyone's input. If it is not going to hurt anything I will wait until winter to repair it. I'm planning on a converter change this winter.

Don