4R55E problems.

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Hello,
I have a ford explorer 1996 4.0L. I have lots's of probleme whith my trans.

The car works fine when then engine is cold, after when the trans is hot,I have some troubles whith the transmission ( slow engagement in front,in 4 gear).

I found out some codes: P0751 & P0756.

So I change the both solenoides & I rebuild all my trans ( I've done it more 10 times for other trans whitout probleme).

After refix the trans,I've the same probleme whith the same code.
So I was disapointed and I rebuild the trans for the second time ( every time whith a new rebuild kit from transtar).

The same trouble again, so I make the job again for the 3 times, and I have the same troubles & the same codes.

I have check my harness, I've change my PCM.

I am going to be crazy about this , Please HELP ME.
Thanks.

 

[BrooklynBay]

Did you rebuild the valve body in addition to the transmission? Did you clear the codes before reinstalling the transmission?

 

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I don't rebuild the VB but I change it and the torque converter too. I had delete the codes after the rebuild,and before testing the trans I check if there's a code stored and I found no codes.he

I know that's the PCM found some informations from the engine for the transmission, so I Have change the MAF, the IAT sensor, The thermostat.
Exactely the same problem.

(I'm a french guy, sorry for my poor english).

 

[BrooklynBay]

I saw that you checked your wiring harness. Is this the PCM harness or the internal transmission harness? Did you check the internal wiring harness? It might have open (electrically broken) connections.

 

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I've check the both(PCM harness & Internal harness) & they have no damage.

The problem is when the trans is hot .Like I loose the hydraulic pressure, But I check the radiator & the pipe line.

When I drive in D position I loose the trans power so I put the trans in 2 position and after in drive.

 

[BrooklynBay]

There is a thermostatic cooler cut off in the valve body which cuts ATF flow when it is cold. It opens when it gets hot. Check this diagram from Glacier991's photo gallery:

The lower part of the diagram has a part which says thermostat bypass.

 

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thanks,
how can I check if this parts is ok ?

 

[BrooklynBay]

There is a special (and very expensive) tool for checking cooler flow. The only other way to check it without this tool is to attach clear high temperature tubing from the cooler return line to the transmission to watch this flow when it gets hot. I would not recommend leaving the tubing in for a long time just in case it can't withstand the stress of the temperature/pressure.

 

[mijube]

Hi there,

I checked the thermal element, by cooking it to 65° C and it opens. But you can push the needdle easily back

Is there any way to bypass the thermal bypass? So the cooling cirquit will be open for ever?

Michael

 

[BrooklynBay]

There is something in one of the rebuild kits for bypassing it.

 

[mijube]

Thx BB,
I hoped that you did know, what this kit is changing in the VB, to bypass the thermal element.
And, or wher to get it.

 

[BrooklynBay]

I think it's either made by Sonnax or Superior, but I'm not sure. You could contact tech support from either company or check their website.

 

[Vikane]

I have the exact same problem as topic starter, what was the solution for this problem ?