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TR4/4A How to test Overdrive out of the car

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Hi all
Phil did send me a gauge and I am very impressed with his help. However, now that I have measured the pressures, I still have a problem.
So I hooked his gauge and I tested the pressure just spinning on the starter. Slowly crept up to 400 psi so I felt comfortable to proceed.

I started up the engine, tranny in 4th gear and increased RPM to 1500-2000. The pressure went up to 410 when I engaged the control valve by hand, it dropped to 370 and within 3 or 4 seconds went back up to 410. Same when I energized the solenoid.

However, the OD did not seem to engage. I hooked up the speedo and I did not see any appreciable change in speed (40 mph or so) with the solenoid engaged or not.

After I shut the engine down, the pressure stayed up until I operated the control valve a number of times. First time down to 250 second time down to 100 third time down to 30 and slow dropping after that without any further fiddling.

So my question is: why won't the thing engage?
Again kudos to Phil. Anything I can do to repay his kindness is on the table.
 
Hmm, what happens if you try to run it in reverse (with the solenoid not engaged) ? Be gentle, don't force it if it doesn't want to turn. If it appears to lock up, then your OD is staying engaged all the time, probably a stuck OD clutch.

I would check the operating valve just because it's a lot easier than pulling the unit apart. Use a magnet to fish the ball out, inspect the ball for any rust pits or visible damage. Use a bent paperclip to fish out the stem and check that the drain hole is open and not clogged with debris or crushed. Put it back together and check that the ball moves up by 1/32" or so when you lift the solenoid plunger by hand.

But from your description of the way the pressure acts, I doubt the valve is the problem. You could try warming it up and see if the clutch pops loose, but my guess is that there is something wrong internally.
 
Hi Randall.
I'm glad you are chiming in. I did put it reverse and was able to turn the engine by hand with no problem. I guess I'll hook up the radiator and the electric cooling fans so I can run it for a bit. Since it's on the test stand, I don't have a clutch. So I'll put it into 4th and run the engine tweaking the control valve from time to time to see if I can bust the stuck whatever loose. FYI this trans hasn't run for 15 or 20 years. It had oil in it but the safety switches didn't work so it's only a guess how long it's been non-op.
Any idea how much an OD rebuild is and who does it? What a money pit!
Al
 
Yow! Double Yow!! At that price I will tackle the job myself. Buckeye has a pretty detailed procedure and the parts don't seem that expensive. First of all I'm going to try to loosen it up by running it. Oh I see that this price was for the whole thing including the transmission.
Thanks Randall
 
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