Lurch, Shudder, & Die....WTF??

chadhargis · **Posted:** Tue Jan 20, 2009 11:04 am

Twice in the past week while stopped at a traffic light, my Jeep has lurched forward (even with the brake applied), shuddered (as the engine began to stall), and died.

The first time it happened, I thought it was a fluke, but it happened again this morning.

Not only is this not completely safe as if I were closer to the car in front of me I'd have hit them, it sounds REALLY nasty.

On both occasions, I popped the transmission in neutral and restarted without any issues.

What the heck is going wrong?? Any ideas. I'm assuming this is not a good sign, especially since I'm out of warranty.

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

My bet is the transmission/TC is giving up the ghost. Time for a Suncoast install and a tranny cooler.

nursecosmo · **Posted:** Tue Jan 20, 2009 2:50 pm

Did your Suncoast come with any kind of warranty?

retmil46 · **Posted:** Tue Jan 20, 2009 3:09 pm

Try stopping by a tranny shop that has a full-up OBDII diagnostic scanner, not the code readers like they have at the auto parts stores. There can be some "hidden" trouble codes thrown, that won't trigger a CEL or show up on a basic code reader.

That's the only way I was able to discover that the Scangauge II was causing the TCM to reboot itself and cause the tranny to drop out of gear at speed - no CEL's, nothing on a basic code reader. But when my tranny guy hooked up his diagnostic scanner, he found the trouble code for the TCM losing power/signal and rebooting itself.

chadhargis · **Posted:** Wed Jan 21, 2009 12:48 am

I've got the Suncoast, and I unhooked my Scanguage a long time back.

I've never experienced this problem before, and it's a bit disconcerting.

gmctd · **Posted:** Wed Jan 21, 2009 12:36 pm

I agree with retmil46 - take it for a Mr MoService scan - or, first might try a SGII scan: it doesn't cause any contention unless the KJ is moving, and thus could display the recent problem or\and future trend

CRDMiller · **Posted:** Wed Jan 21, 2009 5:03 pm

chad, hi again :P

Super stupid Idea, check fluid level.

I was about 3 qt low after a filter change (and retard flush) (yeee hawww) and I had this exact thing happen 2x in same day, While cold. Some how (apparently) the tc locks up and you stall i assume it's due to the lack of pump pressure in some way. Just an idea, good luck!

retmil46 · **Posted:** Thu Jan 22, 2009 3:39 am

CRDMiller wrote:

chad, hi again

Super stupid Idea, check fluid level.

I was about 3 qt low after a filter change (and retard flush) (yeee hawww) and I had this exact thing happen 2x in same day, While cold. Some how (apparently) the tc locks up and you stall i assume it's due to the lack of pump pressure in some way. Just an idea, good luck!

Not stupid at all - been stated here often in the past, and by my own tranny guy as well - first thing to check if one of these 545RFE's is acting up, make sure the fluid level is correct.

Sometimes on here we get so wrapped up in these beasts, we end up tripping over our PHD's (post hole diggers), and forget the simple obvious stuff we ought to check first.

Uffe · **Posted:** Thu Jan 22, 2009 3:57 am

CRDMiller wrote:

chad, hi again

Super stupid Idea, check fluid level.

I was about 3 qt low after a filter change (and retard flush) (yeee hawww) and I had this exact thing happen 2x in same day, While cold. Some how (apparently) the tc locks up and you stall i assume it's due to the lack of pump pressure in some way. Just an idea, good luck!

Seems plausible to me - the only way the auto box could move the truck at idle would be because it tried to lock the clutch in.

No matter the gear it selected it can only yield less torque on the wheels than 1st gear (which it is in while idling and in D). So clutch is the only option of jolting it forward.

chadhargis · **Posted:** Thu Jan 22, 2009 9:47 pm

Well, ya know, that's a darn good idea.

Just checked the fluid, and while it's not really low, it is a bit low. I'll pick up some ATF tomorrow and fill it all the way up.

chadhargis · **Posted:** Sat Jan 24, 2009 9:28 am

I put almost a quart in. I can't tell any difference so far, but it hasn't been real cold like it was when it happened the other times.

retmil46 · **Posted:** Sat Jan 24, 2009 1:33 pm

A quart low is getting in the range where that beast would start acting snaky.

Might want to recheck after driving for a while - with our specific setup, the tranny/cooler doesn't easily get rid of residual air in the system. Quite possible it'd take even more fluid to top it off, considering it took nearly a quart on the first try.

When they did my Suncoast install, it took 4 test drives and an additional 3 1/2 quarts of fluid, after the initial fill, to get the level stabilized. A few days later, I had to top it off a smidge more, before all was said and done.

If no obvious leaks, quite possible they didn't manage to get all the air burped out when they did your Suncoast install, and it was running just low enough that it didn't cause problems until the onset of cold weather.

On mine, when it's cold enough, the tranny won't go into 4th or 5th gear and/or lockup until it's ran for 3 or 4 miles and the TCM decides the fluid is warm enough to allow the tranny to do so.

This programming feature, and low fluid level, might be related to your two inadvertent lockups.

Lurch, Shudder, & Die....WTF??

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