Is it true that chrysler transmissions have cooling problems?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

kage860

Full Access Member
Joined
Apr 9, 2013
Messages
161
Reaction score
0
Location
Westchester, NY
http://etereman.com/blog/fiat-transmission/what-problems-plague-the-chrysler-42lre-transmission


Found that on google after reading about the problem here:

http://www.thetruthaboutcars.com/2017/10/piston-slap-ultradriving-budget-beater/

I probably dont care enough to go out and install a bigger cooler any time soon.
 

JasonJ

Full Access Member
Joined
Jul 8, 2013
Messages
1,521
Reaction score
51
Location
Michigan
I'd say it's generally true.... but a lot of factors come into play- how often was fluid and filter changed, was the vehicle ever used to tow, did it tow more than it should have, etc....

I did read that Wrangler owners with the 42RLE like to overfill the trans by about a qt so that when they are on inclines the fluid pump is still able to draw fluid into the transmission... although I do not know if they have a deeper pan than ours or not... so it may not be applicable to a KJ.

It's always a good idea to add an aux trans cooler, or upgrade the existing one, regardless if the trans has a known issue with getting hot. Those articles sound very worst-case scenario/doom and gloom compared to my experience.
 

TwoBobsKJ

Full Access Member
Joined
Jan 28, 2011
Messages
2,637
Reaction score
17
Location
Northern Ohio
http://etereman.com/blog/fiat-transmission/what-problems-plague-the-chrysler-42lre-transmission


Found that on google after reading about the problem here:

Piston Slap: Ultradriving the Budget Beater?

I probably dont care enough to go out and install a bigger cooler any time soon.

Funny how the article says the internet is "littered with stories about the 42RLE" but then goes on to talk about the equally awful Ford AXOD ****** - so the 42RLE didn't corner the market on issues. The thing about the web is you don't take time out of your busy day to comment about how WELL your transmission is shifting and getting you to the local Piggly Wiggly, work, kids ball game and Grandma's house with no issues. We assume they'll work and they usually do. Human nature says we'll talk about things that go wrong before we'll comment on things that are going well.

In 212,000 miles I had two trannies in my '03 KJ - the first one wasn't maintained and took me to 103,000 when the clutches dumped. The PO didn't do fluid changes and that's one thing Chrysler products require is on-time fluid flushes. Second, the KJ has a trans cooler from the factory so the cooling problems those articles mention with the 42RLE are pretty much taken care of from the get go.

I'll use forums like these to help me diagnose and fix issues but I view postings of problems with a grain of salt. The first place folks go these days to discuss problems is the model's forum so of course when you jump on Google and do a search for "42RLE problems" the search engine does it's job and finds problems with 42RLE trannies. Pretty much a self-fulfilling search I'd say. Same for those Ford AXOD transmissions mentioned in the article.

Drive your KJ and enjoy it, do fluid changes on-time and with the proper fluids and your Jeep will treat you well. Will it break somewhere down the road? Probably, but mechanical things break from time to time.

My 2 cents.

Bob
 
Last edited:

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
Like Bob stated, if you are looking for an issue the internet will certainly hook you right up with others who want to complain
No one ever gets on forums and posts every where mine has X number of miles and nothing has broken / worn out yet.
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
I'd say it's generally true.... but a lot of factors come into play- how often was fluid and filter changed, was the vehicle ever used to tow, did it tow more than it should have, etc....

I did read that Wrangler owners with the 42RLE like to overfill the trans by about a qt so that when they are on inclines the fluid pump is still able to draw fluid into the transmission... although I do not know if they have a deeper pan than ours or not... so it may not be applicable to a KJ.

It's always a good idea to add an aux trans cooler, or upgrade the existing one, regardless if the trans has a known issue with getting hot. Those articles sound very worst-case scenario/doom and gloom compared to my experience.

In some cases the aux. trans cooler could in fact keep the fluid too cool causing some issues . Automatics are designed to work at a certain temperature. Heat is a huge cause of transmission failures but running too cool is bad also. Just as an engine has to run hot enough the trans has to run hot enough to get rid of any condensation that builds up inside and to keep the viscosity at the correct level for best operation. Depending on how a trans cooler is installed it could help or in some cases hurt the trans.
 

Aceofspades

Full Access Member
Joined
Jan 24, 2017
Messages
803
Reaction score
107
Location
Buffalo
^ true. I can't get get lock-up on my convertor until the trans temp goes to 185 on my other vehicle and well with a huge cooler I added. My 5 mile winter morning rides to work it almost never reaches it
 

JasonJ

Full Access Member
Joined
Jul 8, 2013
Messages
1,521
Reaction score
51
Location
Michigan
Good info .. good info.

I wonder if my Innova 3160d displays transmission temperature from the OBD system.... wish we had a gauge for that.
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
^ true. I can't get get lock-up on my convertor until the trans temp goes to 185 on my other vehicle and well with a huge cooler I added. My 5 mile winter morning rides to work it almost never reaches it

I used to add oil coolers to all my Harleys but of course had to cover them when temps went down or was not a good sound LOL When riding at 25-30 degrees almost had to install a heater in front of the cooler :happy175:
 

HoosierJeeper

Gold Supporter/Admin
Staff member
Administrator
Joined
Jan 20, 2009
Messages
20,855
Reaction score
266
Location
Western WI
My trans overheated once, but I think a slipping torque converter caused it to overheat which then made it slip even more. Never got the idiot light on though. Had to get a rebuild.
 

tjkj2002

Full Access Member
Joined
Dec 17, 2006
Messages
10,612
Reaction score
39
Location
Somewhere between being sane and insane!
^ true. I can't get get lock-up on my convertor until the trans temp goes to 185 on my other vehicle and well with a huge cooler I added. My 5 mile winter morning rides to work it almost never reaches it

You got a trans issue if your not going into 4th till 185 degrees ATF temp,should be 80 degrees.



As far as the 42RLE and heat issues.............................

The stand alone trans cooler is the whole issue,adding a bigger stand alone cooler is not the answer either.You need to swap in a radiator from a 2002 KJ with the 45RFE and mod the trans cooler lines to run through the in-radiator trans cooler(built into the '02 radiator) and then to the OE stand alone cooler,then back to the trans.
 

Leeann

Full Access Member
Joined
Mar 9, 2013
Messages
2,436
Reaction score
241
Location
Maryland
^ true. I can't get get lock-up on my convertor until the trans temp goes to 185 on my other vehicle and well with a huge cooler I added. My 5 mile winter morning rides to work it almost never reaches it

I have a 2 mile drive to work. My Liberty is up to full temp before I reach halfway and will go into lockup long before that.
 

HoosierJeeper

Gold Supporter/Admin
Staff member
Administrator
Joined
Jan 20, 2009
Messages
20,855
Reaction score
266
Location
Western WI
x2. Mine locks up the first time I'm at an appropriate speed. Holds gears a tad longer when it's cold, but that's programmed in to help heat up the trans.
 

TwoBobsKJ

Full Access Member
Joined
Jan 28, 2011
Messages
2,637
Reaction score
17
Location
Northern Ohio
You got a trans issue if your not going into 4th till 185 degrees ATF temp,should be 80 degrees.



As far as the 42RLE and heat issues.............................

The stand alone trans cooler is the whole issue,adding a bigger stand alone cooler is not the answer either.You need to swap in a radiator from a 2002 KJ with the 45RFE and mod the trans cooler lines to run through the in-radiator trans cooler(built into the '02 radiator) and then to the OE stand alone cooler,then back to the trans.

That's what I did - and I'd link to the thread but all the pics are gone thanks to Photobucket :favorites68:

Bob
 

renegade 04

Full Access Member
Joined
Jan 3, 2014
Messages
1,466
Reaction score
18
Location
Albany New York
On my libby I have a dual core all aluminum radiator with the in radiator transmission cooler as well as the Mopar extreme temperature external cooler and the jeep loves it. I have never seen temps above 160 since I installed the set up.
 

djtimyd

Full Access Member
Joined
Aug 17, 2017
Messages
134
Reaction score
1
Location
Colorado
isn't the engine temperature supposed to be warmer? I'm not talking 220°+, but isn't the factory thermostat a 195°? IIRC, the jeep will run rich - ie dump more gas than it needs to when its colder, in a vain attempt to get it up to normal operating temperature.

I could be wrong here... its happened a time or fifty.
 

djtimyd

Full Access Member
Joined
Aug 17, 2017
Messages
134
Reaction score
1
Location
Colorado
OK, I thought so... but the post by renegade 04 confused me with talk of the replacement dual core all aluminum radiator. Apparently I got easily distracted by another shiny object.

How does one monitor the transmission temperature? Does the Mopar Extreme Temperature External Cooler come with a gauge?
 

HoosierJeeper

Gold Supporter/Admin
Staff member
Administrator
Joined
Jan 20, 2009
Messages
20,855
Reaction score
266
Location
Western WI
You can't monitor it unless you add a sensor. I think PML makes a pan that has a bung for it.
 

tjkj2002

Full Access Member
Joined
Dec 17, 2006
Messages
10,612
Reaction score
39
Location
Somewhere between being sane and insane!
On my libby I have a dual core all aluminum radiator with the in radiator transmission cooler as well as the Mopar extreme temperature external cooler and the jeep loves it. I have never seen temps above 160 since I installed the set up.

Mine normally runs about 160-170 with the stock radiator cooler and 28,000lbs GVWR trans cooler.Will creep to 170-180 on the trail but that is expected.
 

Latest posts

Members online

Top