• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Torque converter causing low rpm engine lope


NAXJA Forum User
Hi everyone, long time lurker, first time poster. I appreciate this forum so much! Bear with me on this one, could really use some guidance.

So a buddy brought me his 1999 XJ with the AW4. Trans fluid puking out the front seal, and he had a shop quote him $2500 to put a new torque converter and front seal in.

The problems were a bit more than that, the flexplate was cracked, the torque converter bushing was gone, seal bad, converter bad, accelerator cable almost cut in two, O2 sensor wires burned to a crisp on the manifold, needed spark plugs, both front axle u joints were toast, tie rod ends bad, drivers ball joints smoked, drivers door pin bushings gone, rear door wouldn't open from the outside handle, etc. Pretty much a basket case lol.

So I r/r all of it, along the way it had faulty torque converter solenoid code thrown, which I assumed was from previous problems with TC. cleared that code after I put new one in. I replaced the section of O2 sensor wires up by the manifold, soldered and heat shrinked each one, and put a new O2 sensor in since it was throwing that code as well.

Fast forward to now... it's starts and runs good, then after driving it and getting it warm, the idle sounds like the motor has a wicked cam. Lopes big time, no codes are thrown (airbag light is on tho ?), and it sounds as though the torque converter is causing it, based on the sound of what I assume are the clutches engaging. It will lope for a awhile with some noise coming from the TC, not loud but you it's not quiet like I think it should be, then it's as though the clutches disengage and the motor runs smooth for awhile and then back to loping.

It makes me think the pump is cavitating in the trans, then it catches prime and it smooths out, then loses prime and starts to lope, rinse repeat. Since it was puking fluid before, there wasn't really any way to see if was doing this before since the trans could never get up to pressure.

As of now, no codes are showing, and it seems to shift just fine. Fluid is at a good level. It doesn't lope when cold, only after running it and getting everything warm.

Could it be the clutch solenoid? intermittent pump? Would love to hear what you guys think.

thanks in advance
I doubt it's the t/c solenoid. Usually when that fails, it just doesn't lockup in 3rd or 4th. You used dex-III and not ATF4+, right? If it's shifting okay and not dropping out of gear, I'd think hydraulic pressure is fine.