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deanfootlong 12-26-2012 02:52 PM

stalling only when coming to a stop
 
Hello all, first of all, please excuse the cross post that I have made here. I posted this on jeepforum.com but Im new to the scene and not sure which forum gets the most action. so, Im posting my issue here as well for the most input I can find. I have been searching for the past weeks on this issue on multiple forums with no definitive results.
car is a 2002 GC 4.7HO with 545RFE tranny. 182k miles. The issue I about to describe has been ongoing for the past FIVE years and hasnt gotten any worse. This is my brothers Jeep and I am contemplating taking over ownership with it with plans to get this thing running properly.

the jeep runs great. seems to shift smooth and operate completely normal for an automatic transmission. It is having an intermittent stalling issue only when coming to a stop. its completely unpredictable. it will be driving just fine, shifting through the gears like butter, then when coming to a stop sign, its as if you were to leave a manual transmission in first gear and come to a stop. a brief buck and stall. the way he has been getting around this is to switch to neutral upon coming to a stop. as soon as the jeep comes to a stop, you can switch back to Drive and it will idle just fine at a stop. its just the coming to a stop and initial stop that creates the issue. my brother has replaced the TPS and IAC as well as cleaned the hell out of the throttle body. hes gone through to check for vacuum leaks and replaced most all of the vacuum lines with no fix. I would think that if it were the crank angle sensor or cam angle sensors, it would do it more frequently and also in neutral. I tested to see if the tq converter was locking up at 45 mph and it is. brake switch is unlocking the tq converter and functioning as normal. the fluid doenst smell burnt. so I dont believe its a burnt out clutch transmission issue. I am thinking its an intermittent electrical issue. a friend mentioned that its possible its the lock up solenoid not unlocking the tq converter when coming to a stop. and that its also possible that its the input or output speed sensor on the tranny not providing a proper signal for the solenoid to unlock. but, as mentioned, it locked and unlocked at 45 mph as it should.

what order of operations would you all proceed with in order to eliminate what may be causing this issue first?


Thanks for reading! I appreciate any input.

Charles

Frango100 12-26-2012 03:52 PM

Re: stalling only when coming to a stop
 
Welcome to the garage, the best site of all:D.
This indeed seems to be a Torque Converter Clutch (TCC) which is not unlocking. If it was engine related, it should still do the same even if you put the transmission in N. It could be a sticking TCC switch valve. Unfortunately this valve is inside the transmission oil pump assy and can only be accessed after removing the whole transmission first. There is an other control solenoid, named the TCC/LR solenoid, which is part of the TRS/solenoid block inside the transmission. This same solenoid sends pressure to the LR clutch, depending on the solenoid switch valve position in the valve body, as also to the TCC control valve. The LR clutch is in fact only pressurized in reverse (but this will go via de manual valve and not the TCC/LR solenoid) and during the first part of being in first gear. Since you mention that you could see the TCC be activated at 45 mph, it seems that the TCC/LR solenoid works ok.
Did you already put a scanner on it, to see if any transmission fault is stored?
A speed sensor fault could eventually cause the TCC not to unlock, but i would expect shifting issues than as well. How about the transmission fluid changes, where they done in time? It could eventually also be the torque converter itself

deanfootlong 12-26-2012 04:07 PM

Re: stalling only when coming to a stop
 
thanks for the info.

the first thing we (friend and I) did was take the scanner to it to check for faults. none stored.

Since you mentioned shifting issues, it reminded me of one time that I experienced something odd. I was rounding a right turn getting on to the freeway and the jeep must have been in 3rd. I pressed the gas to accelerate and the RPM's climbed but it did not down shift to 2nd. It continued to struggle to accelerate and eventually downshift to 2nd. So, possibly the tq converter was locked in third? I really dont think it was a slipping issue as I SHOULD have noticed it more than just that one time.

Im honestly not certain when the last time the fluid was changed but I would say its probably due. tho it doesnt smell burnt and still appears red.

So, since the transmission wuold need to be removed to access the TCC solenoid, what things should I replace while its out? should I go ahead and just replace the tq converter and all other accessable solenoids?

can you point me to a place that will pin out all these solenoids you mentioned? I seem to be having a hard time finding resources that show where these solenoids are and where to buy them. so far for the 545RFE Im only finding the solenoid pack and I am uncertain what solenoids are in that pack. **upon rereading your post, are you saying that all those solenoids you mentioned are inside of this solenoid pack? http://transmissiontechnologies.com/...lenoidpack.jpg

Frango100 12-26-2012 07:29 PM

Re: stalling only when coming to a stop
 
Yes, all solenoids are inside the TRS/solenoid pack. There are 6 solenoid valves, 5 pressure switches and 1 pressure regulator solenoid inside this pack. This white solenoid pack you show here fits perfectly on the 1999/2004 WJ's, but you also need a new TRS selector plate. (originally the 1999-2004 WJ's came with a black connector pack, but the white connector pack seems to be better. The black one is also not produced anymore, you can only find them refurbished) I bought mine at www.electricaladvantage.com
The price is right and the service quick/good (no, i don't know the guys personally and am not shareholder of the company:D). I also bought at the same time the 2 speed sensors and line pressure sensor.
But at this moment its still a guess where exactly the problem is. Could you get your hands on a DRBIII scanner or comparable, then you could monitor the transmission while driving and you could see if the TCC is applied or released and a lot of other input/output info, which maybe could help with the trouble shooting.
It could be an expensive exercise to replace just any part which could be the culprit.
I just did a complete overhaul of my 5-45 tranny and it is quite some work to get the transmission out, so you better know exactly what has to be changed before starting to tear it appart.
And regarding the tranny not downshifting, that also could have many reasons. It only happened once, so difficult to say what it was. When the transmission downshifts, it should first release a bit one of the 2 clutches who are in use at that moment, to let the engine speed up enough to make the shift smooth, then it completely releases the clutch and applies an other one. There is a certain overlap in this process.

deanfootlong 12-27-2012 12:29 PM

Re: stalling only when coming to a stop
 
ok. thanks for the info, frank. I think I may start with a basic fluid and filter change and see if that helps this issue any. it may be possible that some debris has gotten into the solenoid.

last night it happened again when the tq converter locked up in third gear when rounding a corner and wouldnt downshift. so its confirmed that the tq converter isnt unlocking at times.

if after changing the tranny fluid and filters its still bad, I'll consider dropping the tranny to replace the solenoids. I think for now, I'll just continue to deal with the occasional stall when coming to a stop. this has been going on for five years anyways.

Frango100 12-27-2012 04:46 PM

Re: stalling only when coming to a stop
 
You donīt have to drop the tranny to replace the solenoid block. When you just remove the pan, as for a fluid change, you can take off the valve body, where the solenoid block is mounted on. Only for the torque converter change or eventually the servo switch valve, you would have to lower the tranny.
When it was me, i would change the fluid, filters, solenoid block and speed sensors. The solenoid block will cost about USD 280 and i paid around USD 90 for both speed sensors and the line pressure sensor (all OEM parts from electricaladvantage)
When you have the valve body on the bench already, you could also install a transgo shiftkit in it at the same time:D

deanfootlong 12-27-2012 04:48 PM

Re: stalling only when coming to a stop
 
ok. I misunderstood you. makes more sense now. know where I can find a chiltons or similar online about changing the solenoid block? since im dropping the pan and pulling the filters.... may as well change the solenoid block while at it. ...and speed sensors for that matter.

deanfootlong 12-27-2012 04:52 PM

Re: stalling only when coming to a stop
 
so this would be the correct solenoid block to order for my application, correct? Mopar 45RFE Solenoid Block - Oem New ! Save Here ! !

Frango100 12-27-2012 04:54 PM

Re: stalling only when coming to a stop
 
I just made an update on my previous post regarding the solenoid block and speed sensors. It all depends on how much you want to spend on it.
Regarding a manual, i would recommend the original jeep service manual. You can find it when googling for free and you will be happy to have it when other problems arrise.
You donīt know anybody with a good scanner, which will show the transmission info? It could help finding the exact cause, without changing unneccessary parts.

deanfootlong 12-27-2012 05:08 PM

Re: stalling only when coming to a stop
 
so the solenoid pack sold by electrical advantage doesnt require me purchasing a TRS plate, or it does?

deanfootlong 12-27-2012 05:10 PM

Re: stalling only when coming to a stop
 
I think I'll change the solenoid pack and see if it fixes it. then I'll move on to the speed sensors if needed since those are external.

Frango100 12-27-2012 05:12 PM

Re: stalling only when coming to a stop
 
Yes, when you change from a black connector solenoid block to a white connector block, you will need to change the TRS plate as well. It came together with the solenoid block when i bought it.


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