Does it hurt tranny driving with no Torque converter lockup?

troy · Oct 16, 2008

My '98 AW4 is choosing not to lock up the Torque converter. By reading this forum, I've come up with a bad Torque converter or TCM. Engine light comes and indicates open circuit for torque converter.

Will I hurt my tranny driving without the lock up? I'm actually getting 1-2 mpg better in mixed driving. I really can't find the time to fix it for another couple months.

TIA

Troy

Littlewhitexj · Oct 16, 2008

I had the exact symptoms in mine a few weeks ago. I pulled and cleaned the NSS and all is well now. I would try that first.

troy · Oct 16, 2008

Good tip. NSS gets cleaned up first.

bigalpha · Oct 16, 2008

From what I understand, bad TCMs are fairly rare. AFAIK, you should not have any problems driving w/o torque converter, but you may suffer a penalty in gas mileage at cruising speeds. If I'm wrong, someone correct me.

troy · Oct 16, 2008

I was told on another forum that the trans would build up more heat without the lockup feature.

kennzz05 · Oct 17, 2008

let us know what becomes of this, my 98 did the same thing i finally went to a tranny shop supposed to a reputable one they did all the police and fire dept in the area ,they said i needed a rebuilt but i had 290,000 on it so i dont know

Hellbent · Oct 17, 2008

troy said:
My '98 AW4 is choosing not to lock up the Torque converter. By reading this forum, I've come up with a bad Torque converter or TCM. Engine light comes and indicates open circuit for torque converter.

Will I hurt my tranny driving without the lock up? I'm actually getting 1-2 mpg better in mixed driving. I really can't find the time to fix it for another couple months.

TIA

Troy

you should be fine. highway mpg may suffer a little, and the trans fluid will run a little bit warmer due to the slipping of the unlocked converter. i drove my beater cheby for over a year with the lock up solenoid unplugged because i didn't feel like pulling the valve body apart to fix it, never hurt anything. think of all those th400's, 350's, c4's, and c6's that went a couple hundred thou with no lock up and standard in-the-radiator trans coolers...

johnnyc · Oct 17, 2008

This also happened on my 98 on the way to Moab last week. I got the 700 and 740 codes, relating to the torque converter. It still drove fine, but on a couple of occasions, it wouldn't downshift on inclines.

And I guess the tranny fluid got a little hot a couple of times. Fluid would come out of the vent tube and spill onto the exhaust, creating a James Bond-type smoke screen.

All was fine on the return trip home though. So next on the to-do list is to install a tranny cooler.

kennzz05 · Oct 17, 2008

looks alot like my ride 98 white 2dr also without the smoke thou

troy · Oct 17, 2008

Does anybody have additional write-ups on the NSS. I searched and all I could find was the www.Jeepin.com article.

I'll clean the NSS and report back if it helped my issues.

lawsoncl · Oct 18, 2008

Since the TCM is throwing a code that says open-circuit, I would suggest actually measuring the solenoid resistance with a meter to see if its within spec. On the TCM connector for a 1998, pins 11,12, and 13 are the wires to the solenoid. I think 11 is the tc lockup solenoid. Unplug the connector and measure their resistance to ground. Should be 11-15 ohms I believe.

Littlewhitexj · Oct 18, 2008

troy said:
Does anybody have additional write-ups on the NSS. I searched and all I could find was the www.Jeepin.com article.

I'll clean the NSS and report back if it helped my issues.

the jeepin article was the best one I found. his way of removing it is the best.

hit it with some PB blaster for a few days before to help loosen it up too.

ehall · Oct 18, 2008

Try replacing the TPS

bigalpha · Oct 18, 2008

ehall said:
Try replacing the TPS

Test it first to make sure it's toast, though.

h2opete987 · Oct 18, 2008

troy said:
Does anybody have additional write-ups on the NSS. I searched and all I could find was the www.Jeepin.com article.

I'll clean the NSS and report back if it helped my issues.

http://www.go.jeep-xj.info/HowtoNSSrebuild.htm

go-jeep has some good writeups as well

Does it hurt tranny driving with no Torque converter lockup?

troy

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Littlewhitexj

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troy

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bigalpha

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troy

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kennzz05

basic dumbass

Hellbent

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johnnyc

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kennzz05

basic dumbass

troy

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lawsoncl

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Littlewhitexj

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ehall

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bigalpha

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h2opete987

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