2002 Dodge Gr.Caravan w/ 41TE Ratcheting noise,Stationery shift from N to D

Jason_SXT

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Vehicle came in with slight geartrain noise... Disassembled trans & found metal in pan, #6 thrust bearing shredded, planetary pinion gear teeth chipped on all pinion gears, but trans. operated normally other than the noise... Cleaned & Rebuilt trans. with new planetaries, new thrust bearings, new friction discs, new steelies, new TC, new filter, & new input clutch assembly... Flushed the cooler, & reinstalled trans. & test drove... Geartrain noise is gone... However, after the trans. fluid warms up a bit, the vehicle can be stationery with your foot on brake, & move the gear selector from Park or Neutral to any forward gear position & there is a hydraulic ratcheting sound much louder than the normal noise of the solenoid pack... I searched STAR Online & found case number that described this condition exactly... It involved removing the EATX control relay from underhood PDC & attempting the shift with trans in limp-in mode (pretty much taking all electronic control away from trans. including solenoid pack)... I did this, & the noise was not there when I performed the stationery shift from N to D... According to the STAR Case, it instructed to replace the solenoid pack if noise went away with EATX relay removed... I figured maybe some of the metal that was all over the trans. got into the solenoid pack & caused this problem, so I replaced solenoid pack... The noise is still there... I then contacted STAR Center... The guy from STAR Center & I agreed that the noise has to be hydraulic/electrical & not mechanical... We also agreed that the problem has to be in the UD circuit due to the noise only happening for the first second of a stationery shift to any forward gear (D, 3, or L) & doesn't happen again until the next stationery shift from P or N to a forward gear... I'm going to R&I the valve body again, & totally disassemble & inspect the valve body because the guy from STAR Center told me about a case from 2004 in which the tech replaced the solenoid pack for the same reason that I did, & the noise never went away for him either... This tech replaced the valve body, & it fixed the problem, but the tech never informed STAR Center of why this repaired the condition (i.e. stuck check ball, stuck valve, etc.)... Has anyone else had this problem after a rebuild? If anyone has any experience with this problem or has any ideas, please let me know... Thanks...
 

Transman

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Have you done a re-learn on the computer? Have you checked the pinion factor to make sure the correct tire size is entered? What solenoid pack did you use (new, reman, used, late/update)? Have you checked to see if there is a flash available on this PCM? Did you dis-assemble the VB on the first trip through? What method did you use to flush the cooler lines?
I have never had anything more than normal buzzing after overhaul but I am fairly confident in the trans itself. These are very good units. I also cannot remember the last time that I found the need to replace the VB on one of these. Any problems after overhaul has almost always related to updating the PCM or solenoid/sensor issues. I will assure you that they do take a bit of time to relearn on their own, even after a "Quicklearn" and the proper pinion factor. Please answer all my questions but I feel the trans just may need some time and miles to get it all figured out. Cheef may have some thoughts also. Transman
 

Jason_SXT

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Yes, I performed the Quick-learn procedure & checked the pinion factor also... We used a known-good used solenoid pack that was replaced on another 41TE because it was leaking leaking like some of them sometimes do... We recently bought a few seal kits from a new parts-provider... We then cleaned, & resealed the solenoid pack before we installed it on the vehicle... (trying to save the customer some money if we can)... I've checked for flash updates & the software is the most current for this vehicle... No, we didn't disassemble the VB on the first trip through, but we disassembled & cleaned it today... No debris found in the VB @ this time... Inspected nylon check-balls for damage, & inspected all valves & passages for damage or debris... We didn't find anything at all... As for flushing the cooler... We used an electric flusher machine & Mopar Transmission flush fluid followed by a quart of ATF+4 to flush the transmission flush fluid out of the cooler & lines...

After cleaning & pretty much reconditioning the VB today, I filled & checked the fluid level in the trans. & took the vehicle for a test-drive... It still makes the noise... But this time, I barely got it onto the street & the trans. went into limp-in with a P0992-- "24/OD hydraulic pressure switch test failure"... I hooked up the trans. simulator (Miller #8333) & according to the results of the diagnostic procedure for that DTC, I was instructed to R&I VB and look for damage... If no damage or debris was found, replace the solenoid pack... I am very confident that the VB is cleaner & in better condition than it was before I cleaned & reconditioned it... As for the solenoid pack, what are the chances that this solenoid pack (which didn't cause any problems in the last vehicle it was in except for leaking) would be causing this same noise or the pressure switches in this used solenoid pack would just go bad all of a sudden today... The pressure switches were operating great with no problems just yesterday... All connectors & wiring are in good condition...

I cleared the DTC & attempted another test-drive with DRBIII riding shotgun... This time, a "Loss of Prime" DTC set right after I pulled the vehicle out of the shop... So I pulled it back in, & verified fluid level... The level was fine... Pulled up a diagnostic procedure for this DTC, & was instructed by the procedure to pull pan AGAIN, & check for debris in pan or plugged filter... The filter was replaced @ same time as the rebuild was performed, & still looked clean when VB was being cleaned & reconditioned today... If no problems were found in pan or with the filter, I was then instructed by the procedure to replace the front pump assembly which is still the original pump... I can see the front pump causing the "Loss of Prime" problem, but I don't see the relationship between the front pump & the hydraulic pulse/ratcheting noise that I'm still chasing... There has to be a common denominator in all this that I'm just not seeing (other than the fact that I took on this job... :giveup)...

This is getting nuts... We're playing with the idea of throwing a Reman Trans. in this thing just to get it out the door & get on with something else... I hate giving up on a problem... Like I said, I would bet money that this problem is Hydraulic & not Mechanical... I would also bet money that the problem is in the UD circuit... However, so far, I haven't found any damage or problems with any components yet... Pretty much everything has been replaced, reconditioned, or is a "tested & known-good" part (with the exception of the front pump, the case, transfer shaft, & differential)... Speaking of the differential, I did have the cover off during the rebuild to inspect for the updated differential pin & to clean any debris from the differential area... I found that the updated pin-keepers were already installed & that there was no damage to differential...

I think I also forgot to mention earlier that the rebuild kit was the Master Rebuild Kit from MOPAR Parts...

I also looked at the CVI's & found the following...
LR = 48 ... 24 = 68 ... OD = 102 ... UD = 47
I was given updated CVI ranges from STAR Center during my call a few days back... They are as follows...
LR = 30-60 ... 24 = 30-60 ... OD = 80-130 ... UD = 30-60

Therefore, the only CVI that is out of range is 2/4 & I was told that it wasn't out of range far enough to worry about as a cause for this problem...

I would greatly appreciate any ideas that anyone may have... I'm running on fumes on this repair ouch...
Chrysler STAR Center doesn't have a clue, & neither do I...
The noise is still there, & now new problems are sprouting while diagnosing the noise... |!!|
 

Transman

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When you put the solenoid pack in, did you use the "Updated" one or the older style? they can be tricky to overhaul if unfamiliar, all solenoids & pins need to go into the exact position they came out of. Did you replace the boot seals inside or just take the halves apart to reseal? Frankly, rather than replace the unit with a reman, I would replace the solenoid pack with a new, updated one that you leave the plate off. The cvi and loss of prime can come from the solenoid pack also. They also have some problems with the connector at the solenoid AND at the PCM, check for corrosion. The info is very helpful that you have supplied and much more than we usually get to help with. Post back, Transman
 

Jason_SXT

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Updated style... Replaced all boot seals, three pressure switch springs & seals, & outer case-half gaskets...

Good news... The noise is gone... Bad news... I found out what happens when you get frustrated & in a hurry...
You end up looking at the picture of which direction the 2/4 accumulator piston goes in it's bore instead of the way that the UD & OD accumulator pistons go into their bores...
In other words, I've had the UD & OD accumulator pistons upside-down in their bores ever since the rebuild... The funny thing is that the trans. shifted fine the whole time that they were upside down... It was operating as if the springs were left out totally... The TCM must have been compensating for the harsh shifts by adjusting the applications of the shift solenoids or something, because there were NO harsh shifts like I would have expected with an accumulator problem... Good thing is that no components were harmed by this mistake... As for the Loss of Prime DTC, it has never come back since yesterday... However, the "24/OD hydraulic pressure switch test failure" DTC is coming back every time the van leaves the shop for a test-drive... I've got a hunch that I may have accidently flipped one of the pressure switch seals while resealing the solenoid pack... SOOOO, tomorrow I'll be putting the original solenoid pack back on & seeing if that doesn't get rid of that DTC... But right now, that DTC is throwing the trans. into Limp-In mode...

I guess we'll see how tomorrow goes... Like my auto-tech instructor always said, "The lessons that are learned the best, are the lessons that are learned hard..." I guarantee that accumulator pistons will be correctly installed from now on... Lesson learned the hard way...
I'm pretty sure it won't be the last... ouch
I had a feeling that it was something simple causing the noise... & the new DTC's that have cropped up during the diagnosis of the noise, have to be because of the used solenoid pack that is on it right now... I guess we'll find out tomorrow when the original solenoid pack gets put back on... My fingers are crossed...
 

Transman

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Thanks for the update and remember mistakes are a normal part of learning. The process goes better if we don't continue to make the same ones but we all make them. Transman
 

Cheef

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FYI....

The CORRECT OEM OD CVI is 48-150. 68 for the 2/4 is high in my book. I do not have my references here with me but the 30-60 on the other 3 clutches is not correct.

People think I am anal about these units, but I manually set every clutch clearance with the proper reaction plate or snap ring. Same goes with the end play on shaft.

My guess is once you have the kinks worked out of the hydraulics in this unit the 2/4 value will come down as it is non-adjustable and is ALWAYS in specification as long as the clutch was assembled correctly and the tapered snap ring has been properly seated on the 2/4 and L/R common reaction plate. My goal for OD CVI's is anything betwen 80-105 and end play between .005 and .012 MAX. I also set that L/R for .035-.037" and never moire than .042" This will insure a low CVI and good down shifts.

I have had a 604 that I rebuilt that had a BAD valve body. Customer brought in to me after 3 rebuilds from other shops. All low mile failures. I rebuilt it once....then rebuilt it once more. The VB had a bad regulator that could not be fixed and pressures were 30% low across the spectrum. Burned every friction in short order and had horrible bump shifts. I try to get pressures on all trannies before rebuild just to amke sure pressures are OK.

Watch the failures to prime and 2/4 codes when they happen together. Indicative of some leak, clog or misassembly.

HTH and that the replacement solenoid works.

Cheef
 
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