FordOmatic troubles, control pressure malfuntion.

Chopshop13

Chopshop13

Member
Hi, Ford o slushy problems here.
Now, its a '53 behind the 239" engines stock and i have just rebuilt the transmision but alas.

So it drives back and forward ok, it has correct 1500rpm stall, and doesn't slip at "stall condition" in any gear.

Problem: With a pressure guage hooked up, the readings are higher than the recomendations across the board, at idle, 1000 and stall. all gears.

were talking round 85-90psi at idle (450-500rpm) 105-110 at 1000rpm up around 160 at stall.

The control preasure rod/throtle valve rod, is not affecting pressure in any position, top or bottom of stroke. apart from neutral and park where pressure increases as rod is depressed. interestingly enough.

We pulled apart the throttle control valves and found a compensator valve in backwards however fixing that hasn't solved anything. Also the throttle control valve appeared to be under (just slightly covered by) the back plate which separates the valve and throttle valve spring, not exactly sure how it should be, so we slid the valve out further so its outside the plate and the small leaf type spring acts on its head. Any comments here?

So still no real answer as to the highish pressure and lack of variation when the lever is operated. your expertise is appreciated
 
Hassn't seen the road, not just because the pressure is a little high, the throttle valve isn't working at all. and the 160 is in D and R.
 
Pressure to light for reverse 180 - 200psi is about right.
Check out your valve body is assemble correctly.
The compensation valve spring pressure controls pressure at idle maybe assemble wrong.
Throttle modulator valve applies pressure to the compensation valve when accelerating to increase pressure.
Check valves are not tight in there bore, they should fall into there bore with no effort. Also check that they are not badly worn, should be no side movement.
 
Ok, thanks heaps. the springs for the converter pressure valve and the control pressure valves are correct.

In regard to valves mentioned by Habbot

Update: so in attemping various things which we may have gotten wrong, we turned the throttle modulating valve around because it is one of the few valves that can go in backwards, and it has fixed the pressure problems, and the throttle is now affecting pressure which is good, psi's are bang on at idle and 1000rpm in R/D.

NO DRIVE anymore in D or D2 at any rpm. Reverse still works fine and so do the D's when jacked up but no forward drive.

There are 2 other valves in the valve body that physicaly can go in backwards so thats our last bet on the valve body. the 2-1 shift valve in the lower body or the compensator valve in the upper. any thoughts?

The air tests check out fine so sleeve on output shaft seems correct. Like ive said at one point we had a strong drive in D and R which is now gone. cluthes bands servos and rear govenor all check out.
 
To clarify, this is a 53 small case air cooled fordomatic with PRNDL sorry not d2.

The idle and 1000rpm pressures are correct in all gears. The stall pressure for reverse is within spec also. but the car wont drive properly in D or L.

Just this morning we put it back on the ground and again, R is ok but we are getting a little forward drive in D/L.

I hink its most likely an incorect valve as is has driven forward well and generated proper stall conditions post rebuild but in trying to fix this pressure problem we may have stuffed it up elsewhere.
As i said air pressure checks show correct band, servo and clutch engagement.

Now, i do have the entire fordo/cruiseo manual, we know it like the back of our hands, but the diagnosis of faults doesn't answer or questions.

We've been through the valve body many times, trying to find fault but were stumped. Next im going to switch the 1/2 shift valve, since that is one of the only other items that can go in backwards.

Problem: The detailed manual does not represent our exact valve body, obviously there were variations, but the diagrams for fordo and cruiseo valve bodys arent quite what we have, hence some confusion over valve orientation and spring arrangement. I really need an exploded diagram of a '53 valve body. Any one?
 
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