Gears & Axles - Is my 10 bolt Torsen unit broke?

Ok i have a 4th gen 10 bolt from an LS1 car in my thirdgen.. Zexel Torsel unit with 3.42 gears.

I noticed the other day the rear end was making some noise when pulling out from a stop and turning at the same time. Rear end would pop/bang kinda sound, but only on slower speed tight turns while moving from a stop.

So i jacked up the car, put it in neutral and started moving the tires. Here is whats happening..I think something is broke but want to know before i swap rears.

When I turn the driver side wheel forward, the passenger wheel will spin in the opposite direction for most of the revolution, but will sometimes stop for a second and then start to reverse rotate for alittle then go back in the other direction. Sometimes it will move very slowly in the opposite direction but not at same speed as driver wheel

When I went to the passenger side and moved it backwards, the driver side did go forward

When i turn the driver side wheel backwards, the other wheel moves opposite way (forward) (occassionally both wheels locked up and moved same direction but hard to spin)
BUT when i move the passenger side forward I would expect the driver to be going backwards but it doesnt move...tries to but doesnt sometimes.



I would have thought turning the driver wheel would always result in the passenger moving opposite and vice versus... but does the Torsen work in this manner?

Kinda hard to explain i guess, you have to try to visualize it

Ok i have a 4th gen 10 bolt from an LS1 car in my thirdgen.. Zexel Torsel unit with 3.42 gears.

I noticed the other day the rear end was making some noise when pulling out from a stop and turning at the same time. Rear end would pop/bang kinda sound, but only on slower speed tight turns while moving from a stop.

So i jacked up the car, put it in neutral and started moving the tires. Here is whats happening..I think something is broke but want to know before i swap rears.

When I turn the driver side wheel forward, the passenger wheel will spin in the opposite direction for most of the revolution, but will sometimes stop for a second and then start to reverse rotate for alittle then go back in the other direction. Sometimes it will move very slowly in the opposite direction but not at same speed as driver wheel

When I went to the passenger side and moved it backwards, the driver side did go forward

When i turn the driver side wheel backwards, the other wheel moves opposite way (forward) (occassionally both wheels locked up and moved same direction but hard to spin)
BUT when i move the passenger side forward I would expect the driver to be going backwards but it doesnt move...tries to but doesnt sometimes.



I would have thought turning the driver wheel would always result in the passenger moving opposite and vice versus... but does the Torsen work in this manner?

Kinda hard to explain i guess, you have to try to visualize it

My Formula has the Torsen rear.
Yes it always worked the way you've described, so you're not dreaming. Usually, most Posi's turn both tires in the same direction.

I know what you're experiencing as I just hurt my rear at a Challenge Series at our local Dragstrip. What noise you describe happened to me and was felt as I turned off the 1/4. I had just experienced some wheel hop for the second time in about 70-80 passes. That's what did it. I do have susp upgrades as you see in my sig.

Find the info on your Differential here: www.torsen.com

Torsen units are not readily available, and are better suited for road race, than drag racing. Tho mine lasted 35k, I drive it allover, and my No P/A Formula runs high 11's.
But after speaking to F-Body racer's, Shop Owners, Tuners etc.
They all agree that you could put the names of all available LSD & Posi differentials up on a Dartboard, and hit such names as Auburn Pro, GM's "Eaton" & GM's Gov-Lok, Detroit TruTrac (taken over by Eaton), etc & you'd still have the same basic problem.

It's a weak link especially with close to 400 RWHP or better and a Stick shift, Drag Radials, etc. (mines an A4).

Don't go crazy. Just fix it now as right as possible, and save up for a larger setup. ie: Moser,Strange, Etc.Etc.

If you get tired of all the opinions, you can pm me if you like and I'll let you know what I did, and try to help you out.
Whatever you do with that 7.5" 10 Bolt you have, make sure you put atleast a "Girdle Rear Cover" on it.

see pics of your diff. here:
http://www.s10forum.com/forum/f13/lsd-or-posi-380890/

Regards...... :secret2:

well i decided to take the diff cover off and peered inside... i have a chip on one of the teeth of the little worm/spider gears inside the unit. Seems like just one chip. I found a very tiny fragment of metal and that is it.

So i dont know if that will severly effect the posi unit function as i am planning to go to the track saturday and dont think i'll have time to swap in another unit tomorrow night. I mean i could get my hands on another 10bolt for now but it would be a long night that i dont wanna spend swapping rears for 1 race.

Then again i dont know if i should risk running it again... with over 800hp going through this thing... i'm surprised it lasted as long as it did.

well i decided to take the diff cover off and peered inside... i have a chip on one of the teeth of the little worm/spider gears inside the unit. Seems like just one chip. I found a very tiny fragment of metal and that is it.

So i dont know if that will severly effect the posi unit function as i am planning to go to the track saturday and dont think i'll have time to swap in another unit tomorrow night. I mean i could get my hands on another 10bolt for now but it would be a long night that i dont wanna spend swapping rears for 1 race.

Then again i dont know if i should risk running it again... with over 800hp going through this thing... i'm surprised it lasted as long as it did.

Exactly what I found earlier this week when we opened it up. That little fine gear had small chip. Very small peices found in gear oil.

The noise started on the return road after a semi final run & I didn't want to chance it, so tho I made it into the final, I just staged to see if the other racer would redlight then took it easy for about 60 feet and then punched it.
info here:
http://forums.corvetteforum.com/drag-racing/2459212-and-the-10-30-09-pbir-moroso-corvette-challenge-winner-is.html

Atleast I drove it home. It's fine on the straights.

Look don't chance racing it, besides the particles may hurt your Ring & Pinion mesh surfaces. :(

btw, did you say 800 hp!? :eek: ....I gotta see pics and info on this build for sure....:suspiciou

my friends did 10 bolt made that popping sound took his cover off and the carrier had 3 hairline cracks... he is currently saving up his money for a 9" so for now we cut about halfway down the cracks and welded it back together... we're just praying that it hold long enough... but we'll see...

Exactly what I found earlier this week when we opened it up. That little fine gear had small chip. Very small peices found in gear oil.

The noise started on the return road after a semi final run & I didn't want to chance it, so tho I made it into the final, I just staged to see if the other racer would redlight then took it easy for about 60 feet and then punched it.
info here:
http://forums.corvetteforum.com/drag-racing/2459212-and-the-10-30-09-pbir-moroso-corvette-challenge-winner-is.html

Atleast I drove it home. It's fine on the straights.

Look don't chance racing it, besides the particles may hurt your Ring & Pinion mesh surfaces. :(

btw, did you say 800 hp!? :eek: ....I gotta see pics and info on this build for sure....:suspiciou


We'll see how it goes, i'm just gonna flush the case and try it. I simply do not have the time to swap it out yet. If it breaks tomorrow then oh well :)

See my sig, i have a twin turbo small block running 12 psi now going for 13 this weekend. Ran low 10's on 10psi, 12-13 should put me at or slightly above 800 crank hp

that setup sounds Heavy Duty!

Well Heat up the tires, drive out about 10-12' and hit the mat & have fun! jmo.
Keep me posted :thumb:

actually swapping out my broke 10 bolt for another working 10 bolt..its 11:30pm haha. THen goin to the track tomorrow

actually swapping out my broke 10 bolt for another working 10 bolt..its 11:30pm haha. THen goin to the track tomorrow

LoL, probably a smarter thing to do that swap, (If there even is anything smart about over 500 HP going thru a 10 Bolt).

Well, how'd it go? :eek2:

btw, how close are you to Monroe? I have a friend who works at one of the Cochrane #1 Stores.

20 min from monroeville. I passed the cochran dealer all the time going to school down in pitt

I got my 2.73 gear 10 bolt in late last night, took the car to the track on more boost and put down 3 back to back to back 10.0 passes at 137-140 mph... Rear held fine :) Love 10 bolt racing

20 min from monroeville. I passed the cochran dealer all the time going to school down in pitt

I got my 2.73 gear 10 bolt in late last night, took the car to the track on more boost and put down 3 back to back to back 10.0 passes at 137-140 mph... Rear held fine :) Love 10 bolt racing

:hail: 10 Bolt Gods Shining down on you for sure.

I'm thinking it launches smoothly, then the Boost Kicks It In The Ass somwhere around 100' out?

Glad it worked out for you after all that last minute thrashing! :rock:
:secret2:

yeah it launches in the mid 1.5 to 1.60 range. No boost on launch but it comes in hard and quick. Probly before 100' thats for sure

my friends did 10 bolt made that popping sound took his cover off and the carrier had 3 hairline cracks... he is currently saving up his money for a 9" so for now we cut about halfway down the cracks and welded it back together... we're just praying that it hold long enough... but we'll see...

lol well ya it didnt hold up I didnt know that you can break a carrier in half lol I guess the DRs didnt help hope we can get a new one swapped in sunday tom.