HI..

I am running a Detroit TrueTrack Limited Slip Diffie in my SC 4Runner. I am noticing a binding with slight clunk noise during turns. This condition does not happen all of the time it seems to come and go.

Other than the occasional noise, the diffie works fine, I have launched it very hard 100 or so times since noticing the binding / clunk and it has not affected the LSD operation at all.

Has anyone else experienced this condition?

Thanks,

Jeff B

 

True Trac shouldn't make any noise. Should be smooth and quiet.
Are you sure it's not a Detroit Locker? They bind and make clunking noises when you turn.
This from Reider Racing:
The Truetrac® is Trachtech’s limited slip differential . This is an all gear driven differential that automatically provides smooth torque transfer for traction on demand. The Truetrac® provides durable and dependable performance with no loss in power and no clutch plates to wear out.

The Detroit Locker® is a fully automatic locking differential well known throughout the years for it’s premium performance and dependable operation. It maximizes traction by delivering 100% of the torque and power to both drive wheels. Engineered to keep both wheels in a constant drive mode, it unlocks automatically to permit necessary wheel speed differentiation.

 

I am sure it is a TrueTrack... it has been installed for 25K miles and just started making noise (after I banged second gear real hard :-)

I am afraid the six puck ACT race clutch is catching up with the weak driveline components. Only strange thing is the diffie is still working fine, I took the photo (see burnout) used for my avatar yesterday which is a couple of weeks after the noise started. I was hoping it was normal for them to make noise after a few thousand miles... probably not

Thanks again for the reply,

JB

 

Update: I talked to Brent, a SALES guy from Eaton (Mfg. of TrueTrack). He told me that running synthetic gear oil could cause the binding that I am experiencing. He suggested changing out the oil.

I did some testing on the way home from work. If I get the rear end to "lock-up" then make a turn under little or no load it binds. It can take quite a few turns to get it to stop binding.

Anyhow... I am going to have it taken apart for inspection and change out of the oil.. I hope the oil is the problem.

 

The Detroit TrueTrac is made by Tractech, not Eaton.

 

This is the reply to my inquiry on the Tractech page:

AUTO REPLY NOTIFICATION
--------------------------

Your email message to 'mlewis@tractech.com' was received by the Tractech Mail Server.

Tractech Inc. was recently purchased by Eaton Corporation.
Your email message was forwarded to the user's new Eaton email account. For future correspondence, please send email directly to the new address.

The recipient's new email address is: XXXXXXXXXXX


Thank you,
Tractech Mail Administrator

 

GL with the problem dood. I'll be in Grand Rapids for Thanksgiving. If you're going to be in town either Thurs. or Friday morning just lemme know.

 

OK.. I will be in GR on Thursday but hanging out at Marcia's folks.. Maybe we could hook up on Friday for lunch ??

 

I recent acquisition...good luck with getting your issue resolved.

 

I have been running the TrueTrac in one of my 4Runners for a long time. No noise except for the tire squeel.

Please keep us posted.

Gadget

 

I will bet you its fluids.

Really !

LSDs are harsh on fluids... use only the best and whats recommended.

I would drain and refil with fresh ..

David

 

Well...

Lots of little pieces and parts were found in the bottom of the pig... all bearings were checked and none were bad so we figure the problem is in the TrueTrack unit.

I called an engineer at Eaton and he told me that he could not believe the unit failed, especially considering it was providing full posi-action till I took it out. He also reported that there is no way to rebuild the unit.

Unfortunately the unit is pretty self contained, I can not see any of the internal components without taking it apart. The engineer told me that if I take it apart I (or anyone else) may not be able to get it back together.

One key point is that I am running the ACT six puck clutch... it is very very harsh and I wonder if it just put too much stress on the TrueTrack.

I had the stock diffie installed for now, I may call Randy's to ask their opinion about rebuilding the LSD...

 

now you know it's toast, but just a question? were you running a limited slip friction modifier additive in the gear oil?

 

Good point about the additive.

JeffB - don't tell them about the clutch and your harsh habits.
But then again, a good friend of mine has one in the front axle of his blown big block nitrous CJ5 paddle-tires shod dunes runner - been there for at least 15 years - no failures. And HE punishes the shiznit out of stuff! (That jeep will do a wheelie on dry pavement with 4 adults on board, I kid you not!) The Truetrac has an excellent reputation for durability.

 

throw in some synthetic, posi additive

all locking units, limited slips, posi, will have some racheting now and again

i would say normal and if not it is going to get louder and worse

i am sure you are all set

 

Hi Kyle,

I ran synthetic oil with no additive

 

that could be a cause of your troubles. some synthetic oils come with addtive, but others don't. it's always safe to dump a tube of it in there.

 

Well... I am not a real patient person so I took the unit apart last night. I never really understood how the thing worked and was surprised to figure out that the three side gear pinions actually bind up against the case to provide lock up. I did not find any Hugh broken parts inside but all of the side pinions are "stuck" into the holes and it looks like they have started to eat into the case side (hard to tell with out getting them out of the case).


Source: http://www.4crawler.com/4x4/TrueTrac.shtml#TrueTrac

I called Randy's R&P ans spoke with a tech. He told me that the unit could develop the problem I experienced if the tires are too tall. I explained my situation (clutch from hell, my driving style & mods) and he thought I might have maxed the unit out. He suggested that I consider the Detroit Locker, I am thinking about it

Later,

Jeff B

 

Could be but the manual states that the additive is not necessary.. The engineer at EATON told me the synthetic oil caused the binding.. If I get the DETROIT LOCKER I won’t be using synthetic (and will use the additive)

Thanks

Jeff B

 

Couple of items; the TrueTrac is only warranted for 31 or maybe 32" tires. Most aftermarket diffs have a small tire warranty, but....

The tires are not the problem. I ran the same true track in three different vehicles, all with 33" tires, for over 10 years w/ nary a problem. It was in 2 gen 1 4Runners and then a gen-2, which it's still in and working great for the new owner (4-cyl version). I have one in my 96 as well.

As to additives - DO NOT add them to the diff. The truetrac, as viewed in the diagram above, is not a clutch type unit and does not need the additive. And TrachTech is FULL OF CRAP if they are saying it's synthetic oil. That same truetrac ran nothing but Amsoil (post gear break-in, twice) for over 10 years now. My 96 is running synthetic as well. The gears should actually react better to the synthetic as it will lube them better.

All that said, driving habits should not be the issue either, unless you're dumping the clutch over and over. But I'd suspect your gears would suffer before the truetrac. I'd certainly consider the Detroit as a replacement, it's a great product and imho has great road manners as well.