transmission shifting funny

[biggjohnson76]

Hi all,

I have a 97 explorer with a 4.0 SOHC, 2WD. I just changed out the transmission with one I purchased from a local junk-yard. The problem is this, when cold the truck has to reach about 2000 rpm's before it will move. After getting it rolling it seems to shift just fine until it gets warm. After warming up the trans seems to lug down the engine then the rpm's will ramp up and transmission starts to "for lack of a better way to put it." buck with the engine rpms dropping and and climbing and the transmission does the funny thing. Not really a slip but more of lull in shifting. Once again after getting up to about 15 mph everything smooths out and acts right. Any Ideas?

 

[manaen]

Did you also change out torque converters, or are you running the one from your old tranny?

 

[biggjohnson76]

I used the torque converter from the junk-yard tranny

 

[manaen]

First off make sure you have the correct fluid level (I assume you do soooo...)

The only way to tell what it going on is to run some pressure tests on the tranny. test both epc and line pressure, my suspicion is that either the torque converter or the EPC valve are not holding pressure. And since it spins to 2000 when cold I lean towards the torque converter. It could also be a blown gasket on the valve body. However there are much more knowledgeable people out here on these transmissions.

You can test the line & epc pressure without removing the transmission, there are two plugs that you can remove and hook a PSI gauge to each of them and then test pressures as follows ( Line psi plug is on drivers side and I believe the EPC is on the pass side)

Edit: you will need a 0 to 400 PSI gauge

Engine at idle
Gear ---- EPC PSI ---- Line PSI
Reverse----52-62-------138-168
Neutral-----32-42-------95-125
D, 2, 1------25-35------80-110

Engine WOT (warning do not exceed more than a few seconds or risk burning up tranny)
Reverse----112-134-----282-350
Neutral-----N/A
D, 2, 1-----112-134-----228-263


Hopefully Brooklynbay will stumble in on this thread, if not you may want to send him a PM

BTW... you should not continue to drive the transmission or it will eventually fry the clutch packs

Good luck....

 

[biggjohnson76]

Thanx for the info. Now, I at least know which way to start looking.

 

[biggjohnson76]

manaen,

in your previous post you referred to pressures "WOT"

What is "WOT"?


Engine WOT (warning do not exceed more than a few seconds or risk burning up tranny)

 

[Xplorer82]

manaen,

in your previous post you referred to pressures "WOT"

What is "WOT"?


Engine WOT (warning do not exceed more than a few seconds or risk burning up tranny)

wide open throttle.