1998 XJ Torque converter stays locked when i floor it uphill on the freeway.

So I've somewhat identified my "power loss " issue. My torque converter stays locked almost all the time, like even at WOT , so trying to floor it uphill on the highway heading up towards the rubicon this last weekend, and on the way home downhill , it was very obvious.

Any ideas what would cause this? Solenoid? It has a brand new Mopar TPS and I adjusted the TV cable countless times. I think having hood vents could have killed my new TPS , since I just changed my last TPS after the last snow run. Ugh, these hood vents are starting to suck.

on my old renix I ran a switch to the TC wiring so I could lock it up and unlock it on my own. Might have to do that if I cant figure this out. Anyone run a TC lockup switch on a late model.

The magic cure-all for lockup issues is almost always the solenoids. A lot of people (myself included) threw a ton of money and parts at the thing without luck, until the solenoid change. They're tricky because they can test OK, but still not function properly. Just replace all of them. There are kits out there for under $100 that include all three solenoids, filter, and pan gasket (check Ebay). I installed this kit last year and all of my shift and lockup issues are gone.

should stay locked until you tap the brakes

if its not downshifting then that's something else, usually related to undergeared axles

5.38s in the axles.
hp60/14b , 40s

It was fine on the way up to the rubicon area on sunday. I think the culprit is heavy rain + heavy hail + hood vents while out snow wheeling killed the new mopar TPS. It wouldnt hurt to try to the TC solenoid as well and do the TPS for the third time this year...

In manual 3rd and 2nd my 92 always locks the TC even if I'm floored. Like ehall said, tapping the brakes will unlock it. I prefer this to help keep the tranny cooler, and always put it in a lower gear on extended climbs to keep it from hunting gears.

trippled said:

In manual 3rd and 2nd my 92 always locks the TC even if I'm floored. Like ehall said, tapping the brakes will unlock it. I prefer this to help keep the tranny cooler, and always put it in a lower gear on extended climbs to keep it from hunting gears.

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ah ok. makes sense. I might end up putting mine on a switch . I really miss having that functionality, but not sure if on the 98 it will throw a CEL , I know on my old renix it did not matter.

blondejoncherokee said:

on my old renix I ran a switch to the TC wiring so I could lock it up and unlock it on my own. Might have to do that if I cant figure this out. Anyone run a TC lockup switch on a late model.

Click to expand...

On my '98 I rigged switching to manually control all forward gears and t/c lock up.
I have a main toggle switch hidden under the dash that enables auto (TCM) or manual control.
My manual control is via a 6 position rotary switch and 1 rocker switch.
The rotary switch layout is as follows;

Pos 1 = 1st gear
2 = 2nd gear
3 = 3rd gear
4 = 3rd gear with t/c lock up
5 = 4th gear
6 = 4th gear with t/c lock up
(T/C lock up in 1st is not possible due to the internal hydraulics of the A4W trans.)

The toggle switch only controls t/c lock up in 2nd gear, I did this because I find myself in 2nd gear a lot and thumb switching take less hand movement that turning a knob.

I mounted these 2 switchs on the shift console cover just rear of the x-fer case shift lever, it is a comfortable / natural place for resting my hand.

The main shift lever still controls how far up range the manual switching will go and also controls engine braking in the appropriate position.

And yes, it turns on the CEL but it resets quickly after returning trans control to the TCM.
I should have a schematic somewhere for this set up but I tend to do a lot of electric mods on the fly, cocktail napkin style.