The Ford Barn

Buford · 03-26-2012, 06:45 PM

I have overhauled my '51 Ford automatic trans...got a kit from Mac's...everything went well and after looking at the rear band I decided to replace it with an exchange rebuilt band.
The symtoms I had were lazy shifting, slipping in reverse and leaking at the converter and the front pump.
Also upon inspection I found several of the bushings were worn so I thought it good to replace the bad ones. Got them from a trans shop in NJ.
Now after overhaul the trans shifts great and I have adjusted the throttle pressure so it upshifts at about 18-20 MPH under light throttle. The bad thing is the rear band still slips when apply throttle in reverse or low range. In drive the trans starts in second gear and that works good.
I have tried to tighten the rear band and can make it so it doesn't slip but it affects the high (third) gear so there appears to be dragging like the band isn't completely released. If I set the rear band like the book says it slips. (Tighten band to 10 ft pounds and back off 1 1/2 turns.) Anybody help?

Buford · 03-27-2012, 07:56 AM

No transmission guys on this site?

Ole Don · 03-27-2012, 08:15 AM

Ask the same question in the late model forum. Similar questions there get more answers.

rotorwrench · 03-27-2012, 06:24 PM

May be a servo or a circuit leak on that band actuator. It seem like there is a way to check pressure. I don't have enough info to be much help on a Ford-O-Matic/Merc-O-Matic from that era. Pressure regulator & valve body valves can get sticky too. THere can be problems with the fluid distributor sleeve in the output shaft. I'll have to see If I can find some info for troubleshooting.

jack orchard · 03-27-2012, 07:17 PM

just a thought...i seem to remember a valve body modification (made by my transmission buddys) to change the trans so that it starts out in 1st gear instead of 2nd gear. (same as cruiseomatic).
while this does not address your problem, if you did'nt already know this, you might be interested....jack

Buford · 03-27-2012, 07:22 PM

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Quote:

Originally Posted by rotorwrench

May be a servo or a circuit leak on that band actuator. It seem like there is a way to check pressure. I don't have enough info to be much help on a Ford-O-Matic/Merc-O-Matic from that era. Pressure regulator & valve body valves can get sticky too. THere can be problems with the fluid distributor sleeve in the output shaft. I'll have to see If I can find some info for troubleshooting.

Great, thanks for the response. I think it has to do with the rear servo as well....I will look at the rear sleeve too...Have put all new rings and seals but still, I could have missed something.
I cleaned all the sliding valves with 600 sandpaper and was careful not to round the edges...all of the valves worked smoothly...
I will keep looking, next I will try to apply the rear servo with air pressure...see where that goes...

habbott · 03-27-2012, 08:01 PM

Check stall pressure. Drop the pan and valve body and do air pressure check on each port. You will need a workshop manual to know which port controls which part should be able to find the cause of your problem.

Buford · 04-26-2012, 07:02 PM

Found the problem! The rear servo piston was in backwards making it impossible to properly sieze the rear drum...the good part of all this is it made the car availible to me as I guess the previous owner couldn't figure it out either.
Anyway the trans works like it should now...thanks for all the input from guys on this site!

03-26-2012, 06:45 PM	#1
Buford Senior Member Join Date: May 2010 Location: La Luz, NM. 88337 Posts: 1,050	Fordomatic help? I have overhauled my '51 Ford automatic trans...got a kit from Mac's...everything went well and after looking at the rear band I decided to replace it with an exchange rebuilt band. The symtoms I had were lazy shifting, slipping in reverse and leaking at the converter and the front pump. Also upon inspection I found several of the bushings were worn so I thought it good to replace the bad ones. Got them from a trans shop in NJ. Now after overhaul the trans shifts great and I have adjusted the throttle pressure so it upshifts at about 18-20 MPH under light throttle. The bad thing is the rear band still slips when apply throttle in reverse or low range. In drive the trans starts in second gear and that works good. I have tried to tighten the rear band and can make it so it doesn't slip but it affects the high (third) gear so there appears to be dragging like the band isn't completely released. If I set the rear band like the book says it slips. (Tighten band to 10 ft pounds and back off 1 1/2 turns.) Anybody help? Last edited by Buford; 03-26-2012 at 06:47 PM. Reason: spelling

03-27-2012, 07:56 AM	#2
Buford Senior Member Join Date: May 2010 Location: La Luz, NM. 88337 Posts: 1,050	Re: Fordomatic help? No transmission guys on this site?

03-27-2012, 08:15 AM	#3
Ole Don Senior Member Join Date: May 2010 Location: St. Michael, Minnesota Posts: 1,713	Re: Fordomatic help? Ask the same question in the late model forum. Similar questions there get more answers.

03-27-2012, 06:24 PM	#4
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: Fordomatic help? May be a servo or a circuit leak on that band actuator. It seem like there is a way to check pressure. I don't have enough info to be much help on a Ford-O-Matic/Merc-O-Matic from that era. Pressure regulator & valve body valves can get sticky too. THere can be problems with the fluid distributor sleeve in the output shaft. I'll have to see If I can find some info for troubleshooting. Last edited by rotorwrench; 03-27-2012 at 06:37 PM.

03-27-2012, 07:17 PM	#5
jack orchard Senior Member Join Date: Jun 2011 Location: summerfield florida Posts: 383	Re: Fordomatic help? just a thought...i seem to remember a valve body modification (made by my transmission buddys) to change the trans so that it starts out in 1st gear instead of 2nd gear. (same as cruiseomatic). while this does not address your problem, if you did'nt already know this, you might be interested....jack __________________ Proud FNG We fixem cars. Heap Good!

03-27-2012, 08:01 PM	#7
habbott Member Join Date: Feb 2011 Posts: 55	Re: Fordomatic help? Check stall pressure. Drop the pan and valve body and do air pressure check on each port. You will need a workshop manual to know which port controls which part should be able to find the cause of your problem.

04-26-2012, 07:02 PM	#8
Buford Senior Member Join Date: May 2010 Location: La Luz, NM. 88337 Posts: 1,050	Re: Fordomatic help? Found the problem! The rear servo piston was in backwards making it impossible to properly sieze the rear drum...the good part of all this is it made the car availible to me as I guess the previous owner couldn't figure it out either. Anyway the trans works like it should now...thanks for all the input from guys on this site!