Rear diff question

[Chris H.]

Hey all!
I'm new to the community, and in fact new to Jeeps, having just bought my first- a 2004 KJ Rocky Mountain, and so far I love it.
The Jeep seems to run well, but I have a question, which I have tried Googling and searching here to find an answer, with no luck.
Now, I'm no mechanic but do have decent mechanical skill and knowledge. I believe I understand basically how an open diff and LSD work. Now I'm not sure if my jeep has the Trac Loc or not, but I don't believe it has anything to do with this anyway.
The situation is: when I'm in 2wd, slow tight turns- no problem, outer rear wheel spins further/ faster than inner rear wheel (open diff). As soon as I put it into 4wd (either high or low) its almost like the rear diff is locking, inner rear wheel now spins at same rate as outer wheel, causing it to skip/ spin in the dirt. I have tried this several times on different surfaces (all dirt) with the same result.
Is there something I'm missing here- I don't think this is normal. Maybe I don't understand how it works as well as I thought. If someone can explain why it is doing this, or if in fact there is something wrong with my jeep, or just any ideas, it would be much appreciated.
Thanks in advance,
Chris

 

[rjkj2005]

It's because the front and back are locked together in parttime. In a turn the back wheels don't move as fast as the front so they bind. Part time is to only be used on wet, snow, dirt, mud, never on dry pavement.
To tell if you have LSD. Jack up the rear so both wheels are off the ground. Spin one side. If the other moves in the same direction you have LSD. If it turns the opposite way you have an open differential.

Sent from my XT1585 using Tapatalk

 

[LibertyTC]

Do you have command trac or selec trac transfer case?
Sounds like with command trac- the front wheels are binding in full turns. Only slippery surfaces as mentioned.
Snow or mud not so much binding, but always take it slow easy in turns when a locking 4x4 is engaged.

You can obtain build sheet via email which will list rear diff type & transfer case info etc.. etc..
Just give your vin # and add I need build sheet / full options listing in link below:
Email Jeep
Trac lok rear end ID: With both rear wheels off the ground turn them, if both wheel spin in same direction, it is a trac lok.
If one spins in opposite direction it is an open carrier.
Trac lok have need for Mopar bottle of limited slip additive to gear lubes.
My 04 Rocky Mtn has trac lok, and clutches were rebuilt in it.
Change rear diff gear lube often, I change every 18 k miles, recommend is every 12 k.

 

[Chris H.]

Thanks so much for the quick replies guys!
It's a Command Trac.
Thank you for the info too. I guess when you think about it technically this all makes more sense now. Its good to know that there's not something wrong with it lol!

BTW, LibertyTC, I saw your photos of your Rocky Mountain- it was the first thing I saw when I first came to the site. Real nice ride man! Mine is stock for now, but you've given me some great ideas! And you are lucky to live out in the mountains man! BC is my favorite place in the country, although I do love being back in NB too! (was stuck in Manitoba for 17+ years and been back in NB for about a year!)

Take care guys and thanks again.

 

[dude1116]

Front and back get locked together, and the rear right and front left wheels are the primary drive wheels, so you'll get that kind of skipping.

 

[profdlp]

Welcome to the forum! :favorites13:

 

[tommudd]

Hey all!
I'm new to the community, and in fact new to Jeeps, having just bought my first- a 2004 KJ Rocky Mountain, and so far I love it.
The Jeep seems to run well, but I have a question, which I have tried Googling and searching here to find an answer, with no luck.
Now, I'm no mechanic but do have decent mechanical skill and knowledge. I believe I understand basically how an open diff and LSD work. Now I'm not sure if my jeep has the Trac Loc or not, but I don't believe it has anything to do with this anyway.
The situation is: when I'm in 2wd, slow tight turns- no problem, outer rear wheel spins further/ faster than inner rear wheel (open diff). As soon as I put it into 4wd (either high or low) its almost like the rear diff is locking, inner rear wheel now spins at same rate as outer wheel, causing it to skip/ spin in the dirt. I have tried this several times on different surfaces (all dirt) with the same result.
Is there something I'm missing here- I don't think this is normal. Maybe I don't understand how it works as well as I thought. If someone can explain why it is doing this, or if in fact there is something wrong with my jeep, or just any ideas, it would be much appreciated.
Thanks in advance,
Chris

Basically you are trying to force the KJ into doing something it was not designed to do. NEVER even on dirt have it locked in and try tight turns , very loose soil, sand, snow sure then you can but the tires have to be able to spin a slight amount.

 

[Chris H.]

Welcome to the forum! :favorites13:

Thank you sir! It seems like a great forum. Thanks again for all the help guys.