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I posted this in another thread but...

The general consensus, it seems, is that the 42RLE basically sucks. Since it looks like I'll be spending money on transmission problems, is there a better transmission replacement that doesn't require major mods?

(04 TJ X; 4.0; 90% road miles)
 

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You could put the older TJ auto in, but not sure how much modding that would require, and nothing that says it will not due the same thing.. I think you said yours had just under 100k in the other thread. Rebuild your current one.. and get another 100k out of it. Also perhaps add a bigger cooler.
 

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Does the 42RLE actually suck? that's where I'm lost. I was under the impression they were more than 1/2 decent. The NV3550 however is a POS in my opinion.
 

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like i already posted in your other thread...

On another note, it seems that the general concensus is that the 42RLE basiclly sucks. What would, or is there even, a better replacement that doesn't require major modifications?
Someone chime in here as this is my last vehicle, I don't want to spend limited money on a bad product if a little more $ would be a yeild better long term solution.
The problem is the computer. The tranny is HEAVILY integrated into the PCM (Powertrain Control Module-engine computer). Look under the hood, theres a 60-some pin TCM wiring harness running from the PCM wiring harness to the TCM mounted by the washer bottle. The PCM and TCM are always talking to each other. The easiest swaps would be a late model AX15 from a TJ, a NV3550 from a TJ, a NSG370 from a TJ (all external slave), a 32RH from an early TJ, or a late model AW4 from an XJ (96 or newer).

Replacing the 42RLE is akin to an engine/tranny/t-case swap. I've looked into it extensively, since I hate my 42RLE. It has been done, its just a crap load of work. Going manual would be easiest. Going to another auto would basically be the same as going to a manual, with some extra work.
1. The 42RLE requires a 1-3/8" input shaft for the t-case, so you may need to change that depending what the new tranny requires. This specific input shaft length is necessary to seal the backside of the tranny.
2. The wiring is a nightmare. To go from a 42RLE to an AW4 would almost involve a complete PCM and wiring harness swap. You would convert to a manual PCM, to eliminate the 42RLE's TCM-PCM communication, then wire the AW4 to receive the torque converter lockup signal as described in Stu-Offroad's AW4 write up. you'd also yank the 42RLE's OD dash switch wiring harness.
3. With the AW4 you also need to redrill all the t-case holes since the clocking is different between the XJ and the TJ. No big deal tho, mrblaine made a jig and will loan it out as long as you return it.
4. If you go AW4, the shifter is different. with AW4's you can shift into 1st or 2nd independently...you only get 1-2, 3rd or 4th. Unless you follow the write up to create a custom control circuitboard to control each solenoid individually. That is a nice thing about the AW4-there is one solenoid for each gear.
5. If you go manual, you need to swap out the brake pedal and install a clutch pedal. the manual would also need the slave and master cylinders.
6. If you go manual, you need to install the PROPER pilot bearing on the crackshaft. Because automatics never have direct contact between the engine and the tranny, they don't have pilot bearings installed on the crackshaft at the factory. I say PROPER because picking the correct pilot bearing based on part number can be a challenge.
7. The starter and crankshaft position sensor are different between the 42RLE and the NV3550. You would need to swap those as well.

As you can see, its a whole lot easier to regear, rebuild the 42RLE & install a Transgo shift kit before swapping trannies.

Does the 42RLE actually suck? that's where I'm lost. I was under the impression they were more than 1/2 decent. The NV3550 however is a POS in my opinion.
the NV3550 is one of the best trannies to come in a Jeep
 

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Who exactly is this General Consensus that says the 42RLE sucks?
 

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I also feel the nv3550 sucks. Maybe it because jeep and the manufacture took 10 years to finally decide what fluid won't screw it up but I personally don't think it is that good for street driving. If you have a trail only rig then it might be different. Imop
 

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The only common complaint I hear about the 42rle is the overdrive gearing. Im running 3.73's and 33's and the loss of power in od is comical. Other than that and the shift points, it has served me well.
 

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wasn't there a tranny the GC used that was like a beefier 42rle, i would think it would be the easiest since it was a close relative.
i think it was a 42rlh or something, it apparently is a very good tranny.
 

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wasn't there a tranny the GC used that was like a beefier 42rle, i would think it would be the easiest since it was a close relative.
i think it was a 42rlh or something, it apparently is a very good tranny.
the WJ's & ZJ's I-6's used a 42RE/A500....and it wasn't that good of a tranny based on what i've read. it's a different transmission than the 42RLE. the 42RLE draws its roots from the 42LE & 41TE (front wheel drive).

the good tranny you've heard of is the AW4 from the XJ - and thats a Toyota transmission.
 

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I know that UnlimitedLJ04 knows his "stuff" but, I have no issues with my 42RLE. 115K and still going strong. I didn't acquire mine until 80K but, I have relentlessly changed fluid and filters since. I am not currently running an aux cooler because of my concern that my 8274 is already blocking enough air for cooling purposes. I like JerryC's new set up though and may go to that.
 

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If properly geared (aka deep as possible in the duff's) and with proper cooling then its a decent transmission I've heard.

I really like my NV3550 though. It has a "truck feel" to it and I like the deep 1rst gear. It just feels tough.
 

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If properly geared..............
I did forget to mention that I am running 5.13s and 35s. Maybe I am lucky, ignorant or a combination of both but, I am content. I did a 4 hour, 2-way commute for 4 months, last year with my current set up and survived.
 

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f9k9 said:
I did forget to mention that I am running 5.13s and 35s. Maybe I am lucky, ignorant or a combination of both but, I am content. I did a 4 hour, 2-way commute for 4 months, last year with my current set up and survived.
I'd say that's a perfect combo for 35s from what I've heard. Its 4.56 for the AW5 or whatever, 4.88 for the NV3550, and 5.13 for the 42re. However some people, especially with the 3.8L go straight to 5.38(?) With 35s. Heck, JIMBOX has 5.38s and 33" tires because that 3.8L likes to rev.
 

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I know that UnlimitedLJ04 knows his "stuff" but, I have no issues with my 42RLE. 115K and still going strong. I didn't acquire mine until 80K but, I have relentlessly changed fluid and filters since.
like anything else with vehicles, there are good performers and lemons in the same bunch. Some have good results, some have bad results.

I'm definitely biased, but I've formed an opinion based on experience, a few off-the-cuff conversations with the dealer and a guy that rebuilds em on a weekly basis.

I've had a lot of issues with my 42RLE, and I bought it brand new. It's spent almost 3 months at the dealership since I drove it off the lot, yet has never been abused. It caught fire at ~15k, died at ~52k, and has always shifted like crap and can't seem to figure out what gear it wants to be in. It's been rebuilt 1.5 times under warranty. It's had the filters and fluids changed religiously every 25-30k...if a major problem didn't arise before it was due. It's got 81k on it now, and I'm saving for the next rebuild...which I expect at, or before 100k.

Unforunately, I'm not alone in my experience...
42rle.... Blown! - JeepForum.com
Help Auto went out How much to pay?? - JeepForum.com
04 lj 42rle to 700r4 swap thoughts? - JeepForum.com
how hard is it to change a tranny - JeepForum.com
Where is the TCM Located? - JeepForum.com

:facepalm:

It can be improved....gears, the TransGo shift kit, a BIG cooler, a temp gauge, and a rebuild by somebody that knows wtf to do. B&G can reflash the TCM, but it costs like $1000 and they never reply...I tried to contact them several times over a year ago and got nothing from multiple email and phone messages.
 

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..........I'm definitely biased, but I've formed an opinion based on experience, a few off-the-cuff conversations with the dealer and a guy that rebuilds em on a weekly basis.

I've had a lot of issues with my 42RLE..................
I am in no way questioning you experience, in general, or your opinion of the tranny that the OP posted about. I am just talking about my limited experience with it. I have good luck, so rarely, that I am euphoric when it occurs. I had a supervisor hit the nail on the head when he told me about my luck. He told me that if, I had a pet duck, it would drown. It has been about 98% correct when/if things have a chance to go south.:rofl:
 

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Hello to all, I see this is an older thread but I have a couple of questions. First off some background info on my project. I have a 04 lj unlimited auto minus engine that burnt from the firewall to the grill and some of the dash melted, it was that way when I bought it and it was bought as a parts only vehicle. I also have a 98 4.0 5 speed complete but bad frame and a 2000 4.0 auto complete with a bad frame. One of either the 98 or 2000 is going to be swapped into the lj body and chassis, that is almost rust free and in very nice shape minus paint. Which would be the best option 98 and 5 speed or 2000 and auto? Im also not sure if I will need new driveshafts, I dont know if the older transmissions are the same length as the newer ones that were in the 04. Basically doing a frame swap but into an lj, leaving the axles in the lj. 3.73 gearing and the dana 44. Thanks for your input!
 
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