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Discussion Starter #1
Hi guys. I have quite a bit of rebuild experience on the older tx's (904, 727, 504 etc.), but not a lot on the A604, 40TE and 41TE series.

I have an '04 Neon, with the 40TE. It has about 134,000 miles on it. The tranny died completely last fall, and I'm just now doing a rebuild. Both the front and rear planetaries are toast. Actually the front planets are completely stripped, and the rear inside ring is partially stripped. Metal chunks and bits everywhere. I had put a new solenoid pack and radiator on it about five months prior to this failure, and everything seemed smooth and fine. My wife drove it for about three thousand miles before any problem appeared. The reason for that repair was due to the dreaded radiator to trans cooler hole, and subsequent passthrough. Plus the solenoid pack was causing codes. I had completely flushed the entire system before replacing the parts, but I did not want to remove the tranny, so I didn't do a rebuild then. Just a note, yes I am using ATF+4.


I want do this rebuild properly, so as to prevent any future problems for at least another hundred thousand miles. I really don't know if the planetary failure was caused by debris in the system, the new solenoid pack, a valve body issue or something else. I have seen some rebuild vendors that have what they call a "repeated planetary failure cure kit", but I don't know if that applies here.


So my questions are: What are the most common possible causes of planetary failure? What can be done to prevent it from happening again? What does the above mentioned "cure kit" do, and what parts are included? What other parts would you reccomend I replace besides a rebuild kit, the planetaries, the bypass valve and filters/gaskets etc?


Any help would be appreciated on this. Thanks --Chris--
 

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My first thoughts would be metal fatigue or lubrication failure.
I have seen this a couple of times in 41TE's in minivans and the cost of geartrain hard parts was so high that I just put a reman and radiator in them and was done.
The transaxle was completely locked-up and had to be moved to the lift with the front wheels off the ground. It was very difficult to disassemble, even with a slide-hammer.
It was a better deal and just more cost-effective to go with the reman.
Metal bits were everywhere and there was no way that I could guaranteee the removal of all of it. Your radiator cooler my also be plugged with shavings. By covering all the bases now will save problems later.
 

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The AXOD tranny in my 87 Taurus failed at 69K miles because of the typical low band breakage. I saw the planetary gears and I doubt that the tranny would have lasted much longer because they were so worn.

"Low buck parts" don't last very long. Every ounce of weight removed adds up to a lighter unit and better mileage and increased profits but life span is reduced. Just my $0.02.

FredB
 

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I really don't know if the planetary failure was caused by debris in the system, the new solenoid pack, a valve body issue or something else. I have seen some rebuild vendors that have what they call a "repeated planetary failure cure kit", but I don't know if that applies here.
The 40TE automatic transaxle failed in my 2003 Neon in May 2008 with odometer at 107,000 miles. It first started to whine, went into limp mode and then failed such that there was no forward 2nd gear nor reverse gear. Dropped transmission pan and found lots of metal shavings. Research on various sites brought me to the conclusion that planetary gearset fails due to lack of lubrication. The overdrive gearset rides on a shaft which is drilled internally to provide lubrication. Since this is a physically smaller transmission than the 41TE used in the minivans, all components are smaller. Thus the drilled lubrication passageways are smaller. However these transmissions are notoriously dirty and dump lots of small clutch material into the transmission fluid due to slippage. This clutch material tends to plug smaller fluid passageways, cause oil starvation and the gearset destruction starts.

Hopefully revised gearset components have larger passageways to prevent this from happening. The only other thing you can do is to flush the transmission fluid at 30,000 mile intervals and hopefully prevent the clogging from happening. Again poor Chrysler engineering on its transmissions strikes again!

I have about 95,000 miles on the complete rebuild of the 40TE since May 2008. I have been flushing the transmission at 35,000 mile intervals so lets hope I can dodge a bullet the second time around. Time will tell.
 

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I have about 95,000 miles on the complete rebuild of the 40TE since May 2008. I have been flushing the transmission at 35,000 mile intervals so lets hope I can dodge a bullet the second time around. Time will tell.
I would agree regarding the fluid changes. I first changed the fluid in the 40TE in my 04 PT at around 110,000 miles. Since then, I've changed it every 40,000 miles. I'm currently over 248,000 miles, and apart from the fluid changes, I've done absolutely nothing to the transmission.
 

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Discussion Starter #6
Well the fliud changes are very important, but that is kind of moot here, since I had already changed the fluid and filters twice in less than 12 months since it got the car.



I'm looking at remanufactured transmisions, but they appear to be more expencsive than I can afford right now. I guess I'll just do the re-build with as many upgrades as I can find, and cross my fingers.

BTW, thanks for the input guys.
 

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Ok, so I found a 41TE with low mileage in a local yard for a decent price. A lot less than the rebuild would cost. Problem is, I don't know if a 41 will work in this car. Does anybody know if the PCM and TCM will allow the 41 to work properly? I know the 41's were used in the '01 to '03 Neons, then they went to the 40 in the '04 and '05 models. If I have to transplant any computers to get it to work, it's probably a dealbreaker. Has anybody tried this before?
 

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I know the 41's were used in the '01 to '03 Neons, then they went to the 40 in the '04 and '05 models
The Neon did not get the computer controlled shifting 40TE transaxle until the 2002 model year. I do not believe the 41TE will fit in a Neon due to physical size limitations. I look at the 41TE in my minivan and it is larger than the 40TE. Somebody correct me if I am wrong. Also was the 41TE bell housing the same as the 40
TE bell housing for mating to the 2.0L 4 cylinder engine? That might be an issue.
 

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Ok, so it doesn't look good for the transplant. I decided against it anyway, due to the technical hurdles and time associated with it.

I went ahead and ordered a full rebuild kit for the 40TE. By the time I'm done, I'll have over $800.00 in it. I sure hope it's worth it. I'm also going to remove the engine and replace the timing belt, water pump, idler, rear main seal and any other items that are too hard to deal with, with the engine in place. With the miles this car has on it, I figure it would be dumb to take a chance on the engine, after spending so much on the tranny.

BTW, I'm pretty sure I know why the transmission failed. When preparing the engine for removal, I decide to flush the trans cooler out. Well, guess what, it was completely plugged. It took full pressure (130psi) from my compressor, going back and fourth several times between the input and output sides to get the clog out. When it did come out, it went so fast, I couldn't even see what it was that was clogging it. Not to mention the fact that it splattered fluid all over me.

The clog surely caused the pump to starve, and a major overheat. No wonder the planets ground themselves to oblivion. I just can't figure out why this happened. I used a brand new radiator, and filters. Plus I drained the fliud, and replaced the main filter and fluid again after 200 miles, just to be sure. It makes me think there might have been an issue with the new radiator. Problem is, I have no way of knowing for sure. I never would have suspected a new radiator would be clogged. I should have checked it. Then again, maybe I did. I don't remember. Of course, the clog could have formed after the fact, but I'm pretty sure I flushed the whole system out pretty good before adding the new fluid. Actually, the more I think about it... I don't think it could have been clooged early on, because my wife put quite a few miles on it before the failure. If the rad was clooged early on, the tranny would have failed a lot sooner. Maybe the core failed in the rad/cooler section.

In any case, I will not be using the rad/cooler any more. I will buy an external cooler for the rebuild. I also bought a magnetic inline filter for the cooler lines. That should be enough protection to prevent this from happening again (crossing fingers).


Thanks for all the help and advice, gang. I'll post an update when finished.
 
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