4R70W trans problem

Reply Subscribe

Thread Tools

Search this Thread

Jul 7, 2003 | 06:56 AM

lobsterman

Thread Starter

New User

Joined: Jul 2003

Posts: 7

Likes: 0

4R70W trans problem

I have a 1994 E-150 with 5.0 engine,my problem is with the transmission.At highway speeds, 55mph+ the transmission will come out of gear,as I let off the gas it will cycle back thru the gears to final drive.This is an intermittent problem,but it seems to happen more often when towing my boat,or when the AC is on. I have a feeling it might be a sensor.I replaced the Output Shaft Speed Sensor with no effect. Any Ideas Out There?

Aug 10, 2003 | 05:23 AM

lobsterman

Thread Starter

New User

Joined: Jul 2003

Posts: 7

Likes: 0

4R70W trans problem

Well, I love my truck again. After replacing the TPS sensor with no effect ,I replaced the MLP sensor. Problem solved.

Last edited by lobsterman; Aug 10, 2003 at 05:28 AM.

Aug 17, 2003 | 06:12 AM

lobsterman

Thread Starter

New User

Joined: Jul 2003

Posts: 7

Likes: 0

4R70W trans problem

After patting myself on the back for fixing my transmission problem, I started thinking.The shop manual says to disconnect the negative battery cable before replacing any sensors,I didn't do that until I replaced the MLP sensor. I read that when you do that, the PCM has to relearn it's shifting strategy. Is it possible the first sensor I replaced was the bad one? Does the PCM recognize a new sensor and adjust shift strategy without disconnecting the negative cable?

Oct 14, 2003 | 06:53 PM

jethro

Junior User

Joined: Jul 2000

Posts: 84

Likes: 0

I am pretty sure the MLP was the problem. I experienced the same problem you had. I replaced the MLP and the problem went away instantly. It's been two years ago with no problems since. I think the problem was a short in the sensor which made the PCM think you shifted into reverse. The computer will force the transmission into a false neutral in order to protect it.