Reverse gear problems, 42RLE W/Command Trac

KJ04 · **Posted:** Sat Jan 27, 2007 11:49 am

I have had occasions when I try to back up in 2wd and even 4hi and there is very little power getting to the wheels. No the wheels are not spinning and yes, I'm locked front and rear. The Jeep barley moves no matter how much gas you give it.

Is there anyone else having this problem in reverse?

tommudd · **Posted:** Sat Jan 27, 2007 12:30 pm

I have noticed it a couple of times on mine, both times was when I was dragging logs out of the woods, (no skidders in Southeastern Ohio :lol:

)and where I was unhooking from the logs it was on a downhill and had to back up a pretty good grade, but only a couple of feet, but took a while and that was with giving it a lot of gas, almost floored. Was in four wheel low both times so I thought that may have had something to do with it.

PBrug · **Posted:** Sat Jan 27, 2007 12:49 pm

I notice this as well when backing up on a hill and in 2wd. If I recall correctly, this was brought up a good while ago and some said this happened because of the way the tranny fluid pan was set-up. Something about all the fluid being in the front, instead of in the rear??? Can't recall exactly.

KJ04 · **Posted:** Sat Jan 27, 2007 12:59 pm

The other day when this happened I was on flat ground, no hill, no incline!
Went to back up in 2wd and didn't want to budge, pulled the lever into 4hi and still barely moved. This is an occasional thing and only happens periodiclly, so far. Never had a problem in 4lo backing up, yet.

I checked the TBS Section and didn't see any mention of it in there.

PBrug · **Posted:** Sat Jan 27, 2007 1:10 pm

No idea about being on flat ground, but like I said I do recall some mentioning it before when being on a hill.

Eddo · **Joined:** Thu Jul 07, 2005 7:01 pm **Posts:** 1214

The reverse gear is very high in the 42RLE. It's almost like 2nd gear in some autos. The 3.7L dosen't have the greatest low end torque, and the low speed coupling of the torque coverter is not great. That is why the Jeep barely move when you let of the gas at idle.

This happens to me all the time. Especially when then trying to back a trailer up. That is why I always use 4-low when backing a trailer.

It really has nothing to do with the t-case. 4-hi just splits torque to the front and rear axles, dosen't multiply the gear ratio like 4wd does. That is why when you put it in 4-low you don't have a problem. 4-low multiplies the torque by 2.72 times.

It's not a fluid pickup problem. The fluid pickup is right in the middle of the pan. If it was a pickup problem then it would happen going up a hill forward or backward, because the fluid pickup is in the middle of the pan.
Also, I believe the recall/TSB was for the 45RFE anyways.

tommudd · **Posted:** Sat Jan 27, 2007 5:21 pm

Thanks Eddo!

Jeepjeepster · **Posted:** Sat Jan 27, 2007 9:25 pm

Now the question is, why in heck did DC put a tranny in the libby like that? It has a tow rating of 5k so they knew alot of people would be backing heavy trailers up and stuff. Ive had this happen to me many times, but never while the land was flat. I live on a fairly big hill and Ive never had troubles backing up it. Only time it happens in when my front wheels drop off the road or something of that nature.

Ive also had it to the floor offroad in R and it didnt move.. I would say its not good on the torque to do that very much..

jason thompson · **Posted:** Sat Jan 27, 2007 9:35 pm

guys like Eddo said and I think that I said it a long while back in another post about the same hing but at the time I was wrong
it all has to do with gearing reverse gear is higher than first and the auto will slip befor it gets enough power to spin the wheels on pavement
the solution=lower gears in the axels thats why you can back in 4lo easy
and having taller tires makes the final gearing higher than what it is ,power to pavement goes down as tires go up
and the 3.7 is not known for its low end torque when compared to the 4.0 I6 in the XJ,TJ,ZJ wich has the same trany

jason thompson · **Posted:** Sat Jan 27, 2007 9:40 pm

Jeepjeepster wrote:

Now the question is, why in heck did DC put a tranny in the libby like that? It has a tow rating of 5k so they knew alot of people would be backing heavy trailers up and stuff. Ive had this happen to me many times, but never while the land was flat. I live on a fairly big hill and Ive never had troubles backing up it. Only time it happens in when my front wheels drop off the road or something of that nature.

Ive also had it to the floor offroad in R and it didnt move.. I would say its not good on the torque to do that very much..

Jeepter
the tow rating of the KJ does not have so much to do with how much it can pull but how much it can stop and control
think about it a TJ rubbi with the same trany can only pull 2K but it has lower gears and the I6? but a TJ 4 banger 5 speed can pull the same?

heck I pulled my brothers YJ on 33" swampers down the highway at 60 mph with the TJ no problem
when I got off and had to stop at a red light it was a new ball game

gone_jeepin · **Posted:** Sat Jan 27, 2007 9:46 pm

Mine hasn't experienced this problem yet, in fact i can get my street tires to chirp in reverse.

tjkj2002 · **Posted:** Sat Jan 27, 2007 9:56 pm

Well looked it up the 42RLE has a first gear ratio of 2.84:1 and reverse is 2.21:1,unlike the 45RFE has a first gear ratio of 3.00:1 and reverse is also 3.00:1.Lucky I got the 45RFE and not the 42RLE!!!!!! It's kinda odd but most autos reverse is almost the same ratio as first gear,weird that the 42RLE is not.

KJ04 · **Posted:** Sun Jan 28, 2007 6:30 pm

OK, I hear what you're saying with reverse being geared higher, yet TomMudd has had the problem in 4lo and I don't, then Gone Jeepin has never had a problem and can burn rubber in 2wd reverse. It's not adding up in my mind to just the gearing.

Skyjump136 · **Joined:** Tue Jul 05, 2005 6:50 pm **Posts:** 1633

Nick, I know what you're talking about. I've had this happen a couple times on pretty much flat ground (maybe a small rock under the back wheels) there is just NO power to the wheels...it doesn't even feel like the Jeep is trying at all. Maybe it is more of a torque management issue (software problem) instead of a gearing issue. It doesn't happen all the time or even under the same circumstances so that's what's got me thinking it might be a computer problem.

sleeve84028 · **Posted:** Sun Jan 28, 2007 6:55 pm

Maybe this an issue of not enough hydrualic within the transmission or in the torque converter that is causing what sounds like a slipping condition based on the description.

jason thompson · **Posted:** Sun Jan 28, 2007 7:11 pm

KJ04 wrote:

OK, I hear what you're saying with reverse being geared higher, yet TomMudd has had the problem in 4lo and I don't, then Gone Jeepin has never had a problem and can burn rubber in 2wd reverse. It's not adding up in my mind to just the gearing.

It is very tough to figure this junk out
I can burn my AT's in reverse and they are taller than stock
mopar trans are picky ,my TJ will not move for the first few seconds after you put it in gear you have to put it in N for a few seconds then go to the gear when it is cold ,even when I drive it daily

I do know that if it happens all the time it is probably gearing not so much trany gearing ,it can slip and has some give, but more diff gearing
or it could be some thing electric geting confused if it only happens some times
I have yet to have it happen to me in fact I have backed up some hills that the hich drug on the way up
I am only riding on 29.5" tall tires though

KJ04 · **Posted:** Sun Jan 28, 2007 7:22 pm

Yes, with me it's just a once in awhile thing that started within the last 6 months or so.
I had hopes, that someone would chime in that actually had it in to the dealer for this problem, along with a solution.

Skyjump136 · **Joined:** Tue Jul 05, 2005 6:50 pm **Posts:** 1633

Had it to the dealership...they said "working as designed." To be honest, I haven't had this happen in over a year so it sort of worked itself out. I have had the trans software updated and swapped to 4.10 gearing...everything seems okay at this point, but I can't say for sure what fixed the problem.

KJ04 · **Posted:** Sun Jan 28, 2007 7:58 pm

Thanks Skyjump and eveyone for your input, I guess I'll just wait and see if gets worse before I go drag it in to the dealer just to listen to their lame proposals. Their favorite being, "we wern't aware of that!" :roll:

I'm beginning to think that L.O.S.T. should hire it's self out to DC as a consulting firm for the Liberty. :lol:

Donkeykong · **Posted:** Sun Jan 28, 2007 11:29 pm

LOL I got half way thru the first page before I realised that this was about AT's....

Weird.

A little off topic, but not too much: when I was looking at the local dealerships this one ____er practically chewed my head off telling me how much metter AT's are than manual. I would love to go back to him with this and ask him to show me this happen in a manual. (I'm also reminded of this each time I drive my wifes car and it's dog of a automatic transmission)
-Mark

Reverse gear problems, 42RLE W/Command Trac

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