Gears & Axles - Ford 9"/True-Trac help




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DDZ/28
05-30-2007, 05:55 PM
For some reason, I'm only spinning the passenger side tire off the line, and sometimes barely spin the driver's side. It's got 4.11 gears & a Detroit True-Trac.

I know the True-Trac's not supposed to do this. The guy that built the rear for me told me to use non-synthetic gear oil with about half a container of that Ford additive. An Eaton rep suggested that I don't use any additive (friction modifier) and while that seemed to fix the problem, there were some pretty strange rubbing/grinding sounds coming from the rear... only when making a slow turn. ie. in a parking lot.

I'm now back to no noise, but one wheel peels :bang:

Any ideas or suggestions? Are these noises normal for a true-trac?


Demon_Speeding
05-30-2007, 10:41 PM
My True-Trac makes little/no noise, and spins both tires. I've always just run a conventional gear oil with no additives. Scott @ DLS built my 9". Maybe you could PM him for suggestions.

DDZ/28
05-31-2007, 07:06 AM
Yeah Scott built mine too. I'll see what he has to say.


turbotko
05-31-2007, 09:11 AM
My tru-trac always spins both tires and doesn't make any noise at all. It will hop the inside tire very slightly if turning really sharp like in a parking lot. I'm running some Castrol synthetic gear oil that we have around the BMW shop here.

Sounds like something is wrong with that trutrac.

Avengeance
05-31-2007, 12:54 PM
No noises here... I didnt use any friction modifier in mine, just non-syn 85w140. Changed the oil after a few hundred break in miles.

Wnts2Go10O
05-31-2007, 02:17 PM
you shouldnt be running additive... theres no clutches in the diff.

blk00ss
05-31-2007, 03:24 PM
you shouldnt be running additive... theres no clutches in the diff.

But that shouldnt cause it to dog leg would it? Sounds like a defect from the factory. I dont know alot about the tru-tracs but i think they work off of spiral gears? Maybe one is stripped or broken? Dunno but you definately shouldnt be dog leggin that baby!

Billy177
05-31-2007, 04:04 PM
I have one in my 70 gto with a 455. the way it works is that it will transfer power to the wheel with the most traction. all conditions equal the left tire will get more traction then the right because more weight is trasfered to it. The strips from my car are usually darker on the passanger side then the drivers side but they awalys both spin. sometimes only one will leave strips however the car will still get sideways from a 40 punch

Wnts2Go10O
05-31-2007, 04:36 PM
But that shouldnt cause it to dog leg would it? Sounds like a defect from the factory. I dont know alot about the tru-tracs but i think they work off of spiral gears? Maybe one is stripped or broken? Dunno but you definately shouldnt be dog leggin that baby!
a gear could be stripped, thats most likely i think. i dont know what else would cause a peg leg in that diff

LS1>girlfriend
05-31-2007, 05:01 PM
I have one in my 70 gto with a 455. the way it works is that it will transfer power to the wheel with the most traction. all conditions equal the left tire will get more traction then the right because more weight is trasfered to it. The strips from my car are usually darker on the passanger side then the drivers side but they awalys both spin. sometimes only one will leave strips however the car will still get sideways from a 40 punch

your wrong, it doesnt transfer power to the wheel with the most traction. if one wheel slips it locks and acts like a spool.

Billy177
05-31-2007, 05:19 PM
your wrong, it doesnt transfer power to the wheel with the most traction. if one wheel slips it locks and acts like a spool.

No it definatly does not, do some reasearch on a torsen differential.

"The Torsen differential is simply a torque multiplier that works through the use of friction generated by thrust forces from the internal gearing. It multiplies what torque is available from the wheel that is starting to spin-up or lose traction and sends that available torque, multiplied by the TBR, to the slower turning wheel with the better traction"

blk00ss
06-01-2007, 12:08 AM
I agree with Billy77....does not act like a locker or spool. Get one tire in a bind(meaning to have one wheel under a load and the other hanging loosely in the air.....the tire in the air will spin while the one on the ground simply does nothing.

EPP
06-01-2007, 05:58 AM
http://www.moserengineering.com/Images/Differentials/truetrac.jpg

DETROIT TRUETRAC TORQUE PROPORTIONING DIFFERENTIAL
The Detroit Truetrac is the first gear type limited slip differential in the industry. Its’ patented design of parallel axis planetary helical gears provide a quiet, automatic splitting of torque. Power transfer goes literally unnoticed by the driver – even in front wheel drive axles.

The Detroit Truetrac performs like an open differential under normal driving conditions and automatically transfers torque to the wheel with better traction when ground conditions warrant. The limited slip responds instantly to torque feedback, anytime, at any speed.

Available for 12 Bolt Chevy cars, Ford 8.8 rear ends, and Ford 9” applications, the Detroit Truetrac’s proven design, low cost and effective performance make it the choice of off-road, street, and strip enthusiasts everywhere.

LS1>girlfriend
06-01-2007, 04:33 PM
No it definatly does not, do some reasearch on a torsen differential.

"The Torsen differential is simply a torque multiplier that works through the use of friction generated by thrust forces from the internal gearing. It multiplies what torque is available from the wheel that is starting to spin-up or lose traction and sends that available torque, multiplied by the TBR, to the slower turning wheel with the better traction"

in this thread we are talking about a detroit true trac and NOT a torsen. read befor you post. the true trac splits torque which means that when one wheel spins it splits torque, so when locked it works like a spool

Wnts2Go10O
06-01-2007, 05:11 PM
in this thread we are talking about a detroit true trac and NOT a torsen. read befor you post. the true trac splits torque which means that when one wheel spins it splits torque, so when locked it works like a spool
the true trac is a torsen type differential...

LS1>girlfriend
06-01-2007, 05:52 PM
huh? what are talking about? zexel torsen is a brand operated by Bosch Corp.

NBM99SS
06-01-2007, 06:41 PM
http://www.moserengineering.com/Images/Differentials/truetrac.jpg

DETROIT TRUETRAC TORQUE PROPORTIONING DIFFERENTIAL
The Detroit Truetrac is the first gear type limited slip differential in the industry. Its’ patented design of parallel axis planetary helical gears provide a quiet, automatic splitting of torque. Power transfer goes literally unnoticed by the driver – even in front wheel drive axles.

The Detroit Truetrac performs like an open differential under normal driving conditions and automatically transfers torque to the wheel with better traction when ground conditions warrant. The limited slip responds instantly to torque feedback, anytime, at any speed.

Available for 12 Bolt Chevy cars, Ford 8.8 rear ends, and Ford 9” applications, the Detroit Truetrac’s proven design, low cost and effective performance make it the choice of off-road, street, and strip enthusiasts everywhere.


Read this again man. Its a type of LSD diff which is what a zexel is

LS1>girlfriend
06-01-2007, 09:28 PM
ok...so he's just comparing one diff to another that are almost the same. thought he was saying its a torsen brand diff. my bad :eyes:

Billy177
06-02-2007, 12:03 AM
in this thread we are talking about a detroit true trac and NOT a torsen. read befor you post. the true trac splits torque which means that when one wheel spins it splits torque, so when locked it works like a spool

reguardless it can't lock and act like a spool

LS1>girlfriend
06-02-2007, 04:24 AM
sure it does, both wheels spin. for the newbs thats all they need to know.