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TJLong1121 11-28-2011 08:54 PM

Transmission / Stalling Issue
 
Here is my jeep info and some background on it.

2002 Grand Cherokee. 4.7L HO.
Transmission: 545RFE
Transfer Case: NV247
Front Axle: Dana 30 186FBI
Rear Axle: Dana 44 226RBA

Changed my transmission fluid and both filters two weeks ago. Things seemed great. Was driving the other day and my MIL/CEL came on. Pulled the code P700 for the tranny. Did some research, was told it could possible be a speed sensor on the tranny. I did some more research and found there is an input and output speed sensor. I replaced the output speed sensor and the light went off and shifts smooth again. Then last night I got home and when you brake hard it stalls now and sometimes in reverse. Read on some forums fluid might be low or something, checked fluid level its good. The fluid is a little darker than I would expect for just changing it, kinda a brown not a bright red.

Not a vacuum leak I don't think, replaced the PVC valve and when I cover it the engine stalls out so its a sealed system... Thinking it has to do with the tranny in some way or another... Just seems weird that all happened after a fluid change...

Thinking about replacing the input speed sensor as well, just dont see that being the issue.

Any ideas?

Thank you!
Tyler

Frango100 11-29-2011 02:13 AM

Re: Transmission / Stalling Issue
 
When you have the P0700 code, it means that you need a scanner to pull the code(s) from the TCM, the P0700 is just a generic transmission code. Did you change the fluid as regular maintenance task, or did you have problems before?
What where the exact symptoms with the tranny when the mil light came on?
When you say it stalls when braking hard, is the engine dying as if you didnīt release the clutch on a manual tranny?
If the tranny fluid wasnīt changed for a long time, the fresh fluid can remove deposites which where settled at some places and this can block certain passages in the valve body or solenoid block. Donīt say this is your problem, but could have to do with it.
So your first step, before changing more parts, is to get the code(s) pulled of the TCM, then you probably know more.
Regarding the fluid colour, did you also smell the fluid, to be sure it doesnīt have a burning smell? Eventhough the fluid colour is not a measure of the fluid condition, it normally doesnīt change to brownish that soon. If you did the fluid change yourself, was the old fluid dark in colour? When changing the fluid by only dropping the pan, there will still be fluid in the cooler and torque converter, which will be mixed with the new fluid after starting up.

TJLong1121 11-29-2011 04:20 AM

Re: Transmission / Stalling Issue
 
I had no problems with the tranny before I did the change. I just bought the jeep about two months ago with 95k. I just hit 100k so figured as a good jeep owner and as preventive maintaince I would do all my fluids. I got $300 in mopar fluids and filters. Did my tranny, transfer case, difs and oil.

When I talk about the stalling, it doesn't stall at every light or anything like that. It bogs down a little at lights like you can tell it wants to die. If you hit the brakes with some decent pressure at 10mph and below it will cause the engine to turn off as if you left it in gear on a manual tranny.

The tranny fluid was very dark when I dropped the pan, I would agree that the old fluid mixed with the new fluid and gave it the off color. That would make sense. The fluid doesn't smell like fresh tranny fluid but I don't know if I would call it a burnt smell....

I know the P700 is a generic code. Still reading around my symptoms were identical to a bad speed sensor. Hard bang in reverse and hard shifts indicating the tranny was in "limp" mode. Like I said, replaces the sensor, shifts were buttery smooth after and the light turned itself off. Since the code is gone can I still have it scannned?

Thanks!

Frango100 11-29-2011 05:43 AM

Re: Transmission / Stalling Issue
 
If the code was not reset, you can still get it out of the TCM.
The stalling looks more torque converter related then the tranny itself. Because its the torque converter who takes the role of the manual tranny clutch, so if the engine dies when coming to a stop, probably the converter clutch didnīt release or some other mechanical failure inside the converter.
The tranny goes into limp mode when a control failure occured and it will stay in 3rd gear.
Bad speed sensor(s) can give harsh shifts, but also a TPS can do. When putting the tranny in reverse, you use a mechanical valve inside the valve body to activate the reverse clutch pack, no electronics involved. Still looks like if the torque converter is somehow at fault.
But to know more, you need the TCM fault code(s) first.

TJLong1121 11-29-2011 09:16 AM

Re: Transmission / Stalling Issue
 
I cleared the code though.....

Frango100 11-29-2011 06:50 PM

Re: Transmission / Stalling Issue
 
Most probably you have only cleared the P0700 code in the PCM, the TCM should still have the faults in its memory.

TJLong1121 11-29-2011 08:52 PM

Re: Transmission / Stalling Issue
 
Well I fixed it folks....

Turns out when I replaced the speed sensor I had unplugged the battery which caused the jeep to reset all its sensors.

My throttle body was dirty, when the jeep tried to use its factory idle settings in its memory and couldnt idle under load of the transmission downshifting at stops.

Cleaned the throttle body real well, reset the computer again, started it up, and I cannot get it to stall no matter what I do!

Kevman 03-20-2013 10:45 AM

Re: Transmission / Stalling Issue
 
bump!.... hows your stalling issue so far? i had similar symptoms after a battery swap on a high mileage 05' 4.7 . TB clean + IACV + TPS replacement seems to have helped a fair bit in my case.


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