Truetrac Owners - Question for you

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

The manual says that to check for "proper installation" you should place the transmission in park and raise both wheels (in this case the front) off the ground and rotate one wheel...the other SHOULD rotate in the opposite direction. Thing is...mine rotate in the same direction! What gives? Anybody else find this to be the case? If not, what am I doing wrong? Maybe I need to be in 4-wheel drive for this to work...so that the pinion shaft is restricted.?.?

unixxx · **Posted:** Sat Oct 14, 2006 11:42 pm

If they rotate in the same direction it means your diff is locked. If they rotate in opposite directions it means it's open. I guess if you don't put it in 4WD you defeat the purpose of putting the transmission in park because the front diff won't be connected to it.

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

Right, and if I put it in 4 wheel drive and the trans in park then nothing is going to move because the front and rear axles are coupled together. So is it even possible to perform this test?

warblade666 · **Posted:** Sun Oct 15, 2006 12:56 am

Most LS diff's will turn the same direction. If you have someone hold one side from turning, you should feel resistance on the other side, but it will still turn. If you do put it in 4wd/park so the shaft can't turn, then maybe it will turn the other side opposite, should be very stiff.

spoonplugger1 · **Posted:** Sun Oct 15, 2006 10:27 am

I haven't owned the TrueTrac, but the Torsen Gleasons I've owned, which is virtually the same design, both turned in the same direction the few times I had the rig up and turning the axle.

Jeepjeepster · **Posted:** Sun Oct 15, 2006 1:19 pm

Hmm, yea, its normal for a diff with an LS to turn in the same direction. isnt the truetrac gear driven though? No clutches? Maybe it works different than a normal LS? Try putting the tcase in parttime like you said and see what happens..

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

Tried the part time thing...but then you can't turn the wheels at all because they are linked up to the back wheels.

Jeepjeepster · **Posted:** Sun Oct 15, 2006 3:24 pm

Skyjump136 wrote:

Tried the part time thing...but then you can't turn the wheels at all because they are linked up to the back wheels.

If the other wheel was going to turn in the oppisite direction it would with the tcase in parttime.

Not that this will help you, I usually stand on the tire and try to turn it to test the Clutches in the LS. I found that they were worn in my dad ford b/c I could turn it with little pressure.

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

Jeepjeepster wrote:

Skyjump136 wrote:

Tried the part time thing...but then you can't turn the wheels at all because they are linked up to the back wheels.

If the other wheel was going to turn in the oppisite direction it would with the tcase in parttime.

Not that this will help you, I usually stand on the tire and try to turn it to test the Clutches in the LS. I found that they were worn in my dad ford b/c I could turn it with little pressure.

Well if that's the case then this TT is one tough SOB and I'll just call it good...cause it ain't movin when its in part time!

unixxx · **Posted:** Sun Oct 15, 2006 8:23 pm

I'd think that:

With LSD:
In part time: No movement
In 2WD: Spin in same direction

Without LSD:
In part time: Spin in opposite direction
In 2WD: ???

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

unixxx wrote:

I'd think that:

With LSD:
In part time: No movement
In 2WD: Spin in same direction

Without LSD:
In part time: Spin in opposite direction
In 2WD: ???

Hey, I agree...just trying to figure out why my setup doesn't jive with what the manual says should happen.

DarbyWalters · **Posted:** Sun Oct 15, 2006 9:26 pm

What "manual" are you talking about? If it is the stock manual then yes the will rotate in opposite directions. Once you install a locker or LSD then they will rotate the same direction.

unixxx · **Posted:** Sun Oct 15, 2006 9:52 pm

This is just a guess, but maybe the threshold is set too low and the diff is locking up before the proper amount of spin is encountered. From what everyone says, you should be fine.

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

The TT manual obviously...guys, I know how a stock diff works and how a typical LSD works. That was never the question. I'm trying to perform the test outlined in the TT manual. Wally, Detroit is saying that with a TT installed that the wheels should rotate in opposite directions...

"FINAL INSPECTION - To verify that the TrueTrac differential is properly installed, restrict the rotation of the pinion shaft, and raise the axle so that both wheels are off the ground. When one wheel is turned by hand, the other wheel should rotate freely in the opposite direction. Check in both directions."

Mine doesn't work that way... Can somebody with a TT just let me know how theirs operates under these conditions. Thanks in advance.

DarbyWalters · **Posted:** Sun Oct 15, 2006 11:39 pm

OK...now that you printed out the instructions...How are you restricting the movement of the pinion shaft? It is true that if the pinion shaft can not turn...the wheels should go in the opposite direction...but the Pinion Shaft will have to remain stationary.

Jeger · **Posted:** Mon Oct 16, 2006 6:22 am

I am having a hard time picturing how to stop the pinion shaft, wouldnt that be the same as stopping the drive shaft.? Ring gear drives carrier, which drives pinion shaft, right?

where's the pinion shaft? I thought the pinion shaft was replaced by gears in the truetrac

Jeepjeepster · **Posted:** Mon Oct 16, 2006 10:36 am

DarbyWalters wrote:

OK...now that you printed out the instructions...How are you restricting the movement of the pinion shaft? It is true that if the pinion shaft can not turn...the wheels should go in the opposite direction...but the Pinion Shaft will have to remain stationary.

By putting the tcase in Partime, it locks the front wheels to the back wheels which are in P by the tranny. He did this and they still didnt turn..

Jegar, I think your just confused.. The pinion shaft drives the ring gear.. The pinion shaft is not replaced by the TT. Only the carrier and spider gears get replaced.

It still amazes me how this thing works. I would love to look at that model they have cut open and spin it to see how it works.. :shock:

Jeepjeepster · **Posted:** Mon Oct 16, 2006 10:38 am

This is my rear diff but you get the idea. The TT would replace that carrier with the Powertrax in it. You can see the pinion gear on the back which drives the Ring gear that get bolted to the TT.. Make sense now? :wink:

Jeger · **Posted:** Mon Oct 16, 2006 11:38 am

What I am calling the pinion shaft is labeled in this picture, sometimes it is called the crossshaft.

it drives the pinion gears which in turn drive the side gears

the pinion "gear" as you correctly pointed out in your pic jeepjeepster drives the ring gear, which in turn drives the carrier with the pinion shaft as well. Maybe part of the instructions they sent you were generic instructions and dont apply to the truetrac?

And yes I am usually confused :lol:

Jeepjeepster · **Posted:** Mon Oct 16, 2006 11:52 am

Since the TT doesnt have spider gears, it doesnt have a pinion shaft..

We were talking about the front drive-shaft, not the pinion shaft you are talking about.. :wink:

I think..

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