904 will not upshift.

[318Duster'72]

1972 Plymouth Duster

318, 904, 3.23.

Put a B&M stage 2 into the trans, now it will not shift into 2nd gear. ops:

Got it up to about 30MPH and no shift, played with throttle/kickdown linkage and band.. Did not help.

Fluid was not burnt or black when drained, and it shifted properly without a kickdown linkage before I got into it.

What could be the cause? ale:


EDIT: I cannot shift manually into 2nd gear.

 

[Corrupt_Reverend]

Can you shift manually into 2nd?

 

[Mopar Tim]

ok how about 1/4 inch steel ball installed behind the 1-2 shift valve instead of the 1-2 shift control valve? B&M info.

 

[TrailBeast]

I seem to remember something about swapping the 1-2 shift valve spring and the pressure regulator spring around causing that.

Of course a stuck 1-2 shift valve can do this also.
Does it have engine braking in 1st ?

 

[318Duster'72]

I also removed the accumulator spring like it says.

I'll see if it worked.

 

[AJ/FormS]

I dont like how a 904 shifts when the accumulator is defeated, for a streeter. JMO.

 

[Mopar Tim]

I dont like how a 904 shifts when the accumulator is defeated, for a streeter. JMO.

It shifts NOW. It is kind of harsh.

 

[AJ/FormS]

Yeah. NOW is right. Feels like the motors trying to rip itself off the biscuits. I usually put the biggest fattest ugliest spring I can find in there. Then work my way back through the collection til I find one that doesnt try to shake the fillings outta my 61 year old teeth.lol

 

[fishy68]

If you inadvertently switched the 1-2 shift valve spring with the torque converter control valve spring it won't upshift. Those springs are real close to the same diameter and length but the torque converter control spring is a bunch stiffer.

 

[fishy68]

I also removed the accumulator spring like it says.

I'll see if it worked.

I don't mind that mod if you also have a real high stall converter that absorbs some of the shock but I really don't like how they say to just remove the spring. That lets the accumulator piston slam back and forth and eventually break. IMO, if the spring is removed a blocker rod should be installed to hold the piston stationary

 

[TrailBeast]

If you inadvertently switched the 1-2 shift valve spring with the torque converter control valve spring it won't upshift. Those springs are real close to the same diameter and length but the torque converter control spring is a bunch stiffer.

That's the ones I was thinking of that might have gotten switched.

 

[fishy68]

That's the ones I was thinking of that might have gotten switched.

I thought maybe it was. A while back we had a guy do that and we were all involved in helping him figure it out. That was a learning experience

 

[diymirage]

and it shifted properly without a kickdown linkage before I got into it.

I thought that was a big no-no with the torqueflites?

 

[fishy68]

I thought that was a big no-no with the torqueflites?

You are correct unless it has a manual shift valve body installed

 

[Bad Sport]

You are correct unless it has a manual shift valve body installed

Sounds as though he was driving it that way before the change.

 

[318Duster'72]

Sounds as though he was driving it that way before the change.

Yes I was.

It still will not upshift, I'm gonna take it in to the shop tomorrow. If they find an issue ill post it.