True Trac issue

How is it possible for one tire to not turn durring a burnout with a True Trac???

This weekend at RPR in Houston EVERY time I went to do a burnout the pass side tire wouldnt spin or it would for a sec and then stop. The car would start to spin and then just start pushing the car. Thinking there was traction I lined up only to blow the tires away.

I pulled the diff cover last night after returning home and there seems to be nothing wrong. I have done the tire spin tests that are in the instructions for the True Trac and they check out.

Any ideas?

Are you using non synthetic lube without friction modifier? Maybe you wore the worm gears out with all that power.

BruceH said:

Are you using non synthetic lube without friction modifier? Maybe you wore the worm gears out with all that power.

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Dino oil only. I guess the only way it could do it is if the worm gear is damaged but, wouldnt I hear something if that was the case?

I never had much luck with those on higher powered vehicles. You would be better off with a Detroit locker if you want a differential and plan to race at the track. Or, you could do like me and run a spool, but I mainly race my car with some weekend cruising.

GB10 said:

I never had much luck with those on higher powered vehicles. You would be better off with a Detroit locker if you want a differential and plan to race at the track. Or, you could do like me and run a spool, but I mainly race my car with some weekend cruising.

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Talked to Eaton today, " must be the oil I am using" lol

I had 85/140 dino in there. Since I see nothing wrong I am going to use the oil that tech guy recomended (Valvaline 80/90) and go do some burnouts on the back roads tomorrow evening and check it out.

If I still have issues, I will tear it down so the parts can get here by the weekend if needed.

this may sound stupid but are you sure you have the True Trac and not just the Eaton limited slip? This is exactly what I did wrong. I thought I purchased the True Trac but instead just got the Eaton limited slip. Since I thought it was the true track I put in the 80/90 regular oil. Had a lot of noise when turning slow. turns out the Limited slip Eaton needs the synthetic and friction modifier.

Doubt that is the same issue you have but it is just a thought.

I've got a truetrac and I've had RP MaxGear 75w90 in mine. Manual says this.

Lubrication
The TrueTrac differential is designed to operate in those lubricants recommended by the vehicle/axle
manufacturer for conventional differentials.

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http://www.eaton.com/ecm/groups/public/@pub/@eaton/@per/documents/content/ct_128482.pdf

GB10 said:

I never had much luck with those on higher powered vehicles. You would be better off with a Detroit locker if you want a differential and plan to race at the track. Or, you could do like me and run a spool, but I mainly race my car with some weekend cruising.

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Hey Luke, how streetable is that locker?

Fish05 said:

this may sound stupid but are you sure you have the True Trac and not just the Eaton limited slip? This is exactly what I did wrong. I thought I purchased the True Trac but instead just got the Eaton limited slip. Since I thought it was the true track I put in the 80/90 regular oil. Had a lot of noise when turning slow. turns out the Limited slip Eaton needs the synthetic and friction modifier.

Doubt that is the same issue you have but it is just a thought.

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Mne is a Truetrac. Thanks though.

Godzirra said:

I've got a truetrac and I've had RP MaxGear 75w90 in mine. Manual says this.


http://www.eaton.com/ecm/groups/public/@pub/@eaton/@per/documents/content/ct_128482.pdf

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Thanks I am going to add the new oil and see hat I can tear up tomorrow. I will either make smoke on both sides or break it.

Jeremy@S&H Performance said:

Hey Luke, how streetable is that locker?

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Even though I'm not Luke, I don't mind street driving with my locker at all. Just takes a little getting used to when to get on and off the gas in a turn but it's not difficult at all.

Jeremy@S&H Performance said:

Hey Luke, how streetable is that locker?

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They aren't bad to me. You have to get used to hearing some clunking noises when it locks and unlocks, but I think they are fine. If you are under hard acceleration and try turning then it is just like having a spool and it makes it more difficult to turn.

Pretty much it acts like an open diff under normal driving and a spool under hard acceleration, so no road course driving, lol.

GB10 said:

They aren't bad to me. You have to get used to hearing some clunking noises when it locks and unlocks, but I think they are fine. If you are under hard acceleration and try turning then it is just like having a spool and it makes it more difficult to turn.

Pretty much it acts like an open diff under normal driving and a spool under hard acceleration, so no road course driving, lol.

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No roadcourse driving is debatable believe it or not... lots of folks running lockers in autocross and on the road course in some older cars that do extremely well on them. Having all of your torque transmitted equally to both tires has advantages coming out of corners!

That said, despite the TruTrac's love with drag racers, launching on gear driven differentials is hell on the diff as all of those shock loads are transmitted directly to the side gears and to the differential case. You would more likely been better off with the clutched Eaton Posi than the TruTrac, especially if you have a lot of power going through it!

Whiskey11 said:

No roadcourse driving is debatable believe it or not... lots of folks running lockers in autocross and on the road course in some older cars that do extremely well on them. Having all of your torque transmitted equally to both tires has advantages coming out of corners!

That said, despite the TruTrac's love with drag racers, launching on gear driven differentials is hell on the diff as all of those shock loads are transmitted directly to the side gears and to the differential case. You would more likely been better off with the clutched Eaton Posi than the TruTrac, especially if you have a lot of power going through it!

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Shows how much I know about road course/autocross Thanks for clarifying on that part.

Thanks for the info. I know im going to have issues with the stock rear eventually lol

i debated on running a lunchbox type locker(aussie locker or lockrite) since they still allow an open differential on the street. the true trac has the same worm gear type internal torque split mechanism as the torsion t2r and i have heard horror stories about them with drag radials/slicks.
OP, i would check the internals out and if they are damaged go grab an open carrier and throw a lunchbox locker in the rear. aussie lockers are suppose to be bulletproof and can withstand a hole boatload of shock loads.
i ended up getting a auburn pro diff instead of the lunchbox locker since i track the car more than anything else but if i were to take my car off the road i would def look into the lunchbox type locker.

The question no one has asked is how are you performing these burnouts?
Do you have a line lock? If you are using your rear brakes thats your issue!!!
Are you also making sure your traction control is off...?

I know these are elementary questions, but I've seen so many people not do correct burnouts.

AutoXRacer said:

The question no one has asked is how are you performing these burnouts?
Do you have a line lock? If you are using your rear brakes thats your issue!!!
Are you also making sure your traction control is off...?

I know these are elementary questions, but I've seen so many people not do correct burnouts.

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Yes I am using the foot brake, is that my issue?

I have a line lock but need to change the wiring. And the traction control is off in the tune.

Billy what happens if you mash the throttle, will it spin both tires.

jewc75 said:

Billy what happens if you mash the throttle, will it spin both tires.

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To b honest I haven't played around with it much like that on the street, maybe it's time to go home tonight put the differential cover back on and go play.

From the way I am understanding the way it works is it sounds like it needs a shock to force out the worm gears. Maybe I'm wrong. I'd try to do a burn out on the street. If that works maybe a linelock will be in your future.