Turbo 400 upshifting too soon

[JMSII]

My turbo 400 in my CJ is upshifting way too soon. (It's in 3rd at about 15mph.) If I manually shift, it shifts nice and hard. I replaced the modulator with one of the adjustable ones but no matter what adjustment I make the problem doesn't go away.

Somebody told me that there was some kind of switch that might be sticking, causing the early upshifts.

The fluid and filter are new, there was no crap in the pan when I changed the fluid, and yes, the o-ring is installed correctly on the filter tube.

Anybody out there a t-400 guru?

[AMX69PHATTY]

Don't Turbo 400's also use a "TV" cable ?
Thought the TV-Cable controled line pressure.
And proper adjustment of the cable was critical.
Thought they also used an electronic kickdown switch.
There's a universal kickdown switch kit available from Jegs.
I use a TorqueFlite, always thought TH350's & 400's were strange
since they used all 3, a modulator, a cable, and a switch.
Haven't done one in an AMC, but helped a friend with his '69 FireBird, what a pain.
I could be wrong, just going by what was in the '69 FireBird.

[1980_Cj7]

I was thinking the same thing. I am not that familiar with the TH 400 either, but our TF 727 uses a throttle pressure linkage to vary the shift points with the amount of throttle being applied. I have also heard that running with out the throttle pressure linkage hooked up and adjusted properly can ruin a tranny pretty quickly.

I'm betting the TH 400 also has some mechanism to correlate shift points with the amount of throttle being applied.

[fuzz401]

TH-400 do not use the linkage like the 727 or 350 just the switch at the gas peddel and the modulator valve that runs of the intake vacumn

http://smg.photobucket.com/albums/v153/fuzzgremlin/TH-400/?start=all

[JMSII]

Thanks! The manual proved to be very helpful!

[junkyard jim]

If a LPS (little piece of $#!t) is stuck in the governor, the trans will act weird like you describe. A pinhole in the hose from the intake (manifold vacuum, not ported vacuum, right? Not off the power brake tee?) will cause late, hard upshifts. Wrong trans fluid will too.

[JMSII]

How does one clean the LPS out of the govenor?

I know the vacuum lines are good and that it is hooked to manifold, not ported vacuum.

I have never had a turbo 400 apart.

Thanks!

[ol' school power]

did this just start one day out of the clear blue sky?

What if you disconnected the modulator line? Do all the gears wind up high?

[JMSII]

With the line disconnected it does not wind up high

[ol' school power]

Above suggestion sounds about right on pulling the governor. At least it's accessible from the outside.

[junkyard jim]

Make sure the pin inside the governor isn't bent (and that it didn't get lost when you changed the governor) You have to take the tailstock off the trans to clean the governor.