727 doesnt want to play nice. Wont kickdown.

Trying to help a friend get his 727 dialed in, and working right.

Back story:
The engine and transmission was removed from the donor vehicle about 2yrs ago. Prior to removal the transmission worked fine, and as it should.

Present issue:
Engine and transmission were put into their new home, now with the kickdown linkage hooked up, and adjusted as normal (full throttle is set for full back position on the kickdown lever at the transmission)

The transmission would shift fast (like no kickdown was hooked up) and would sometimes downshift into passing gear.

Thought it might be a valve body issue, so he swapped in a known working valvebody. Now it still shifts quick like before, and has no kickdown into passing gear. (replacement valvebody has a stage II kit)


A couple of things he noticed.
The donor trancmission he got the stage II valvevody from had no large accumulator spring (the one that is on the pan side). The transmission he has in the vehicle, was missing the small, long accumulator spring that fits towards the inside of the transmission.

It does have the aluminum accumulator piston, and it is in good shape.

When he installed the stage II valebody, he installed both accumulator springs, as he was unsure which spring is often recommended to remove.



What is the probable cause of the quick shift, and no kickdown issue? Could this be governor related?

There were no signs of worn out transmission parts, the fluid was bright read, and had no silt of shavings. The transmission has less than 5000 miles on it.

The accumulator spring(s) have nothing to do with the problem.

If it kicks down "sometimes" the TP linkage adjustment is close but not perfect. (early shifting suggests that too) Be sure that "lever full back" under the hood is the same as full back from inside the car....IOW, the carb might not be going to WOT with the pedal on the floor.

It was adjusted using the floor pedal for WOT, the lever on the transmission is going all the way back, this was verified under the vehicle. And At WOT there is no rear play in the linkage.

Its really weird.

I am no trans whiz by any means!! But I just had a 727 built and SMR told me for the kickdown to work it had to be a 71 and up valve body. The older valve bodies fit but won't downshift correctly. not sure if this helps but call SMR as they are GREAT to work with even if they have a Canadian accent!!

Differential gear ratio plays a part in shift timing.
What may work good for 2:76 might not be the same for 4:10's.

Quote:

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I am no trans whiz by any means!! But I just had a 727 built and SMR told me for the kickdown to work it had to be a 71 and up valve body. The older valve bodies fit but won't downshift correctly.

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That's true of PART throttle kickdown, the OP has no kickdown.