Jeep Wrangler Forum banner
  • Hey everyone! Enter your ride HERE to be a part of JUNE's Ride of the Month Challenge!

1 - 3 of 3 Posts

·
Premium Member
Joined
·
11 Posts
Discussion Starter · #1 ·
In July after many years without a Jeep my wife and I decided to purchase a 2004 in excellent condition body and rust wise but needing maintenance and a few upgrades. It's a Columbia edition with a 4.0, manual and 30/35 axles with no posi. It also had 32" tires so was casual as far as performance goes.

Since we are older and hard core off road is not in our future and because I intend to drive it to work on snowy days I decided to make a few changes. The 10+ year old 32" KO2s came off and 30s went on which helped some in the performance department. I decided to install 4.10 gears and Truetracs front and rear to aid with off road and snow traction. A few weeks ago I had a local shop I trust install the new gears and Truetracs.

Took it out for a couple hour slow off road trip and after about an hour noticed a scraping noise from the left rear on sharp left turns. This turned out to be worn rear drums rubbing lightly after they got warm, I installed new shoes and drums and the noise went away.

While searching for the source of the rearend noise I noticed in left or right turns there was a squeaking coming from the front axle (like twisting a rubber shoe back and forth on a polished floor), this could only be heard at slow speeds with the radio off and windows down. I was pretty sure the noise was from the Truetrac and not the re-gear.

Did some searching on this forum and online about the noise but could find nothing definitive. I did find conflicting opinions about the use of synthetic oil, also in the instructions it stated not to use synthetic in one place then in another said use whatever the manufacturer listed.

Called Eaton and spoke to tech support, explained the issue and this is what they told me. Synthetic will not damage the Truetrac but it may cause inconsistent or no limited slip, possibly noises. He went on to tell me they recently had a customer with the same axles as mine install Truetracs front and rear then go to the beach, stand on the gas and have power to one front wheel and one rear. He told them he was using synthetic and they recommended he switch to mineral and retest, result power to all four wheels. Also told me they don't always see the problem with all installs or all brands of synthetic but since there is no way to tell which combinations have problems they recommend mineral based oils only.

So I drove my Jeep for awhile and confirmed the noise. I then pumped the synthetic out of both axles and filled with mineral based Valvoline. Took for a test drive and for the first 100 yards was noisy as usual then over the next 100 quieted down and has not made a sound since. Now, other than the noise I don't know what the effect on LSD operation the synthetic had but I do have two other Truetrac equipped vehicles, a 420 HP 1952 F-1 and a 500 HP 1970 El Camino both with synthetic. Every once in awhile the limited slip seems not all there, I plan on changing both to mineral based.

Spoke to the shop that performed the work and he told me he considered mineral based but because he knows how I am about my vehicles he put in synthetic not knowing it may cause problems, he won't use synthetic in one again.

I read many posts that read "I have used synthetic for years with no problems", well so have I but unless you are in a condition where the LSD is operating how do you know how well it's really working? For me I'll run mineral, save a little money and change it at a regular interval.

 

·
Retired Moderator
Joined
·
100,727 Posts
:welcome: to the Forum..:wavey:
 
1 - 3 of 3 Posts
Top