Fresh 904 skips 2nd gear

Scott Warner

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First Tqflite 904 rebuild in 30 years.
I got a good kit with alto frictions and kyolene steels. All new seals, all measurements fell within spec.

There was already a proven TF-2 kit in the valvebody which remained intact.

I added a CRT multi spring to the front as the big anti wound coil was weak. Also added new rear and middle aluminum servos. Front band apply servo was left alone.

First drive attempt first gear wound up to about 3k...and straight to 3rd. Only went a couple miles....different throttle positions were tried...no change.

I turned around and got about a block from the house (fully warmed up now) and got 1-2, and 2-3 shifts pulling away from the light. I went another block and it wouldnt do it again.

I readjusted the front band...same result.

Next attempt I only backed off 1 turn from 78 inlbs. Nope.

Left it at 78 inlbs...seems better..but will wear front band quickly.

Thinking I should take a few springs out of the CRT unit.

Thoughts?

And many thanks.
 
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TrailBeast

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First Tqflite 904 rebuild in 30 years.
I got a good kit with alto frictions and kyolene steels. All new seals, all measurements fell within spec.

There was already a proven TF-2 kit in the valvebody which remained intact.

I added a CRT multi spring to the front as the big anti wound coil was weak. Also added new rear and middle aluminum servos. Front band apply servo was left alone.

First drive attempt first gear wound up to about 3k...and straight to 3rd. Only went a couple miles....different throttle positions were tried...no change.

I turned around and got about a block from the house (fully warmed up now) and got 1-2, and 2-3 shifts pulling away from the light. I went another block and it wouldnt do it again.

I readjusted the front band...same result.

Next attempt I only backed off 1 turn from 78 inlbs. Nope.

Left it at 78 inlbs...seems better..but will wear front band quickly.

Thinking I should take a few springs out of the CRT unit.

Thoughts?

And many thanks.
It does sound like a valve hanging up to me as well.
When I was doing transmissions for a national chain we used this stuff when we had sticky valves in the valve body, or sticking governor valves.
It really does work for that.
Might be worth a try, and keep you from having to tear into it again.

4A7E98CE-5279-4093-8B91-353432A0D3C9.jpeg
 

Scott Warner

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Well...it isnt a valve..but close!

I think I found the issue.

The second gear servo pin was stuck in the out position...and appears slightly bent.

Guess I need a servo. The 727 servo is the same one right? I have a 727 core to pull from...or I could spend more money on a
Sonnax 7722830.
 

Scott Warner

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Little more research on my part shows that sonnax number is for a 727.
Does anyone know if they make one for a 904? Or have a spare 904 servo? For a 1969 (small diameter servo)?
 
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Killer6

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It does sound like a valve hanging up to me as well.
When I was doing transmissions for a national chain we used this stuff when we had sticky valves in the valve body, or sticking governor valves.
It really does work for that.
Might be worth a try, and keep you from having to tear into it again.

View attachment 1716014202
That stuff is the sh*t!!
 

Scott Warner

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UPDATE!!!


So it took a while..but with the holidays..and family obligations/emergencies...the servo has been replaced....second gear shift snaps you neck in to place..and it appears my problem was 2 fold. The plunger rod...definitely askew ...but the upper cup gasket failed in a spectacular fashion.
Many many thanks to Duster346. You are certainly a gentleman...and scholar. I will be purchasing all my future trans needs from you.
 
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