Trans Slip

racerx6466 · #1 (**permalink**) 02-22-2009, 05:45 PM

Have a 99 F-150 2wd with a 4.6. Recently (less than 1000 miles ) ago had trans rebuilt. Put it back in and the trans slips going into overdrive. When it goes to shift the motor will rev up before it engages but after that it will engage solid and not slip anymore. It's not so much a slip but more like putting it in neutral, revving the motor, then putting it in drive. And only going to overdrive. Also trans was done for free (by a reputable shop) but free with no warranty and yes the fluid is full. Any help is appreciated

n5926g · #2 (**permalink**) 02-22-2009, 06:13 PM

Sounds like Torque converter...did they replace it when they did the rebuild?

DarrinBC · #3 (**permalink**) 02-23-2009, 07:44 AM

To me it sounds like a valve in the valve body is sticking or an overdrive servo issue.

Darrin

racerx6466 · #4 (**permalink**) 02-23-2009, 02:31 PM

Yeah in fact that is why I had the trans rebuilt. There was nothing wrong with the trans at all but my converter locked up and wouldn't slip. Figured with the converter failure and having the trans out I might as well rebuild since it had 175,000(probably more from gears and tires before the calibration) on it. Darrin is the servo something that can be fixed without dismantling or pulling the trans?

DarrinBC · #5 (**permalink**) 02-24-2009, 09:19 AM

You don't have to remove the transmission, but you do have to remove the valve body and it's kind of tricky to remove and re-install the OD servo.

I can talk you through that if you need me to. As a matter of fact I might take some pictures and create a little article for that.

There is an issue with these transmissions with leakage around the 'pin' on the overdrive servo. I am working on coming up with a better solution than the Sonnax kit for that. Their kit works, but you have to do some work to the case to install it. A lot of guys mess it up and end up cutting the o-ring when they install the new pin.

I don't think it's the torque converter. But, you can test the converter in 3rd gear by using your OD lockout switch and turning off OD. If the converter locks and unlocks properly in 3rd gear then that isn't it.

Darrin

racerx6466 · #6 (**permalink**) 02-24-2009, 12:57 PM

That would be great, I need all the help I can get. I'll probably drain the fluid tomorrow and check it out. Where would I be able to buy the servo

racerx6466 · #7 (**permalink**) 02-24-2009, 01:02 PM

Or would this be what I need AODE 4R70W transmission servo piston,AODE 4R70W transmission parts

DarrinBC · #8 (**permalink**) 02-25-2009, 08:01 AM

That's the correct replacement.

You have to take the valve body down to get to it and you are going to need something to compress it into the bore so that you can remove the snap ring to get it out.

On installing it you are going to need to use a long thin screwdriver to manipulate the band through a hole in the case under the valvebody to make sure it engages the servo or it won't work when you put it back together. This is easy to do, but VERY easy to mess up when you are not used to doing it.

Again, when I get time I will try and do something for some sort of article on a 'how-to'

Darrin