I have been trying to rid myself of gremlins and have gone around in circles. I have a freshly rebuilt 4l60e with a new pump and a brand new Vig 3200. This is in a 01' TA and I have the Transgo kit installed with the Pro-Built modifications. The converter will lock smooth as can be under medium load but on light loads (mostly around 38-41 MPH lockup) it shudders like a mother. I even got together with my trans builder and did the full on PWM pump spring disable to rule out a faulty valve via Transgo. I also replaced the TCC lockup soleniod. I had similar problems with shudder on my last converter which seemed to take out my clutches after it decided to chew itself apart. The only thing that has not changed has been the valve body. I have a decent looking vb form a 96' available to me for no cost and was contemplating swapping it in place of my 01' vb. Since the pwm is made to an on/off setup will this work? I also have the separator plate from the 96'. Any suggestions would be welcome as well.

 

You would need to use the sep plate, VB and the correct gaskets for the 96 and it should work fine . Good luck though there are many other possible causes though pump stator, bushings etc.

 

Thanks for the information. I am hoping that it is somewhere in the vb. Sometimes going with a local builder ends up being more hassle and money than it is worth. I will remember that in the future

 

Before you change anything I recommend you install a pressure gauge and watch line pressure as it becomes symptomatic.

It would not surprise me that you are losing pressure at light throttle and subsequently sufficient pressure to hold the converter clutch.

If your builder installed the PWM mods properly then I doubt it is in the valve body itself... especially if you have been into again and did not see anything of interest.


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My trans shop is closed until Monday so I will wait for this little test so they can see as well. If in fact I am losing pressure at light throttle... where would I start pointing to as the culprit? With the Transgo kit it should have helped a bit with the white spring in the actuator setup and the boost valve. My shifts are not sloppy or slipping under light throttle so this is stumping me. If in fact I am coming up a bit short on pressure is there a way to simply up it via tuning, or in your opinion is this something that needs to be addressed mechanically?