I have a 1991 F 250 that I had the trans rebuilt backin may. Every since then I had a issue with TCC slippage. The shop could never resolve the problem. It always seemed to have low pressure clutchs and such at lower speeds. It would slip bad and over heat at low speeds. I ran a line pressure test and came up with slightly higher then listed pressures across the board. Now today I was going up my drive less then 10 mph. It seemed to have been spinning in mud a little so I nudge the pedal down just a little. Next thing there was a pop noise from the trans and no forward gears would work after that. But, it still has reverse. Any ideas as to where the problem may be? The trans worked better before it was rebuilt then when I got it back. Could there be a bad part in it some where. The mid carrier was replaced with a used one. Since may I have only put about 1500 miles on it. The fluid is full.
Thanks for the ideas.
Bob

 

Likely fwd clutch isn't working. If reverse is normal you have enough line pressure and a working torque convertor. That clutch will require trans to apart. Don

 

I would be screaming warranty at the shop as well!!!LOL

 

Was it rebuilt stock or modified? Did it get th 95 up grades? Is the OD light on? Did you check for any coes? Does the fluid smell burnt? Was the TC replaced?

 

a popping huh. that sound like when i blew all my forward gears myself except i got s squeel and a pop litterally destroyed the transmission went revers in forward range. real fun tim getting that on the 20 ft trailer and pulling it with the jeep. 2400$ later its all better.

 

It was suppose to be updated when it was rebuilt. I was not there to watch the job so I can not say it was done to the full extent. The center support was replaced new pump assy, new HD TC, new valve regulator plus the normal parts. The trans was pulled once after the rebuild due to soft shifting. The pump was pulled apart to find it still had a old style gear set in it. That was replaced.
Codes, before the rebuild I had a 26 and a 62. TPS out of range and TCC slippage. Still had the same problem after. Tps wires where checked Tps replaced. Never reset by a shop. I have talked to a ford shop fallowed their directions for setting it. Consultedin another trans shop, was going to replace the PCM this week with a used unit.
Here is my idea. If the line pressure was always good. There was a leak somewhere beyond that point be it in the valve body or lines to the clutch packs. Would this cause a TCC slipage? I always noticed a slip type of shift around 30 to 35 mph. It just seemed like low pressure. It progressivly gotten worse over the last few short trips to town. 4 miles to town.
The shop owner has about 30 years under his belt. I had ford test the pcm. That came back good. I rewired the TPS to rule out a bad wire. Like I said I was replacing the PCM this week. Now this. Could it have been a leak all this time. Could a air pressure check determine where it is?
Thanks guys
Bob

 

I forgot to add, even in limp mode the shifting was maybe normal at best. Most talk of how harsh they shift in limp mode but this one never did. Is that a sign there was a leak somewhere
Bob

 

First off there is no way that I know of checking the pcm to see if its ok.. second.. even if you take the pcm out of the system it will drive..maybe not shift but it will drive..so dont waste your money on a pcm its internal

 

If you can't get any forward gears by manually shifting down into 2nd or 1st gear then you are probably in big trouble, especially if your oil level is up.

Pull your tranny pan and check for metal in the pan. My guess is the pan is full of metal shavings, etc...

Given the job you got from the last re-builder, find somebody else to do the next rebuilt. It sure sounds like the guys you dealt with don't know what they are doing if they could not resolve the problems you had after the rebuild that was done.

Better luck next time,


Seb....

 

After studing a tech manual I have I come to the conclusion of the forward clutch pack. From the get I think itwas shy either a spacer or a fiber disc. It has slipped enough since being put together that it finally allowed the piston to over travel and POP out. That would explain the pop noise I heard also. I am going to pull it and take it back for the warranty work on it. I am going to use the excuse I never seen one a part to stand there and watch him dissassemble it. I kind of know what to watch for in the multi clutch set ups. These are real simuliar to pto clutchs in tractors I deal with. All a long I knew there was something slipping in that thing. I will keep you guys posted.
Oh by the way after talking to another trans shop and a ford dealer, they both said the volt check is the fastest way to check the tps. The ford dealer did not even have the dauge block to set it with the ford scanner just used a volt meter.
Later
Bob