Gears & Axles - 9" truetrac poping on tight turns

what could this be? say im pulling out of a parking spot, it will pop a few times while im turning. im guessing its in the diff.

More than likely, you know how they actually work?

not 100% on oh how it works but i know its all gear driven. but it just started doing this after i went to the track

You might have broken a Tooth off of one one the Gears..

wow. all runs where made n/a only went 11.9 60ft in the 1.69. 3675 with me in it got 3.90s AND A LS7 CLUTCH.

You might have broken a Tooth off of one one the Gears..

I second that....I know...same problem as you....I've been dealing with it for 1 yr now....going to a spool..

I second that....I know...same problem as you....I've been dealing with it for 1 yr now....going to a spool..
Im in process of ordering a fab 9". Alot of people say get the true trac,, others say go spool. Well with all the stuff im hearing about mid powered cars breaking true tracs, I went with a spool and 4.11`s

Don't be surprise A LOT of people are having the same problem with their Truc Tracs. To me is happening the same thing going only 12.62 with bolt on only..... HONESTLY I wish I would have found about this sonner.

Now I would never recomend a Truc Trac to anyone. I will try to contact them to see if they can at least respond to their product and if the warranty will cover this (clunk, and LOUD Poping noise on sharp turns). Gentlemen this is a manufacture defect. I will make a threath about this. I went through enough problems trying to save money to buy this piece of crap and now its broken.

I'd like to know what is happening and what the problem ends up being with these problems. I have sold literally hundreds of Moser rears with Truetracs, and have heard of very few problems. Please post up what you find out. Thanks. Bob

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.

Mines been doing it since almost day one. I bought it already installed in a 10bolt with 4.10s from a friend of mine. He put it all together and didnt even put it in the car, just sold the whole thing to me. Anyway mine pops sometimes pulling out of the driveway or in a parking lot and it hasnt even seen track time yet. It has seen some street runs with stickey tires but no 5000rpm launches thats for sure.

EDIT: My true Trac just shit itself totally last week. Granted its in a 10bolt, but it never even saw any drag time. Only lasted 4 months of DD.

I bought a used rearend (supposedly nothing wrong with it, yeah right) with a TrueTrac and the popping, clunking, clicking was horrible. Any time I turned sharply, transitioned between accel/deccel, or even put it in gear it would make noises and literally shake the car. The back end of the car would also jerk to one side or the other going down the road when going from deccel to accel. Had the center secton checked out at RPM and he didn't say anything was wrong with the Truetrac unit but I'm not sure the mechanic delved that deep. The pinion preload was way off with the sleeve not even being crushed and the carrier bearings were off as well.
I should be back on the road soon so I will see if that fixed it. I really hope so because I don't want to pull it back out and buy a new unit and then pay to have it set up properly again.

EDIT: I have since found out that the 9 inch had a Locker diff in there and not a Truetrac so that is probably why it had so many problems. Swapping out to a Truetrac....

I had the same problem after a hard launch at the track and when I disected the tru trac the case was cracked and one of the helical gears had ran itself into the case of the tru trac and got stuck. I wish I would have taken pics but I was so pissed at the time that I just scrapped it. I opted for a nodular case, spool, and 35 spline axles from EPP. :devil: Thanks Bob, car is running great now. :D

I had the same problem after a hard launch at the track and when I disected the tru trac the case was cracked and one of the helical gears had ran itself into the case of the tru trac and got stuck. I wish I would have taken pics but I was so pissed at the time that I just scrapped it. I opted for a nodular case, spool, and 35 spline axles from EPP. :devil: Thanks Bob, car is running great now. :D

You're welcome, thanks! Bob

Hmm havent had a problem out of mine yet and have had some low 1.5 60s in mine. If it goes i will prob going spool but until then im gonna leave even harder:D

Mine is not clucking at all beside a bit of gear whine at around 60-70 MPH and light load.

Burklaft had moser make to long of axles for their fabs and had to cut off almost a inch to stop it.

Burklaft had moser make to long of axles for their fabs and had to cut off almost a inch to stop it.

Burklaft or Burkhart as in Burkhart Chassis Inc.? That is who supposedly built mine.

what could this be? say im pulling out of a parking spot, it will pop a few times while im turning. im guessing its in the diff.

Mine is doing the same thing as you. It started doing it after I had some pretty bad wheel hop at the track so Im pretty sure thats what caused it.

Now I dont know what I want to do. Im thinking about going spool just cause I dont drive the car daily but I do like to take it on trips where I could get caught in the rain... which kinda scares me.

BTW I have a 9" incase it matters.

i have a spool in it now, no more popping, i love the spool, its so much fun

i have a spool in it now, no more popping, i love the spool, its so much fun

How often do you drive it on the street? Have you had to drive it in the rain yet? I'm leaning towards the spool but I'm a little concerned about its streetability.

I have a DD but I like to take the camaro on trips so rain is a possibility.

Also did you have to swap out your 31 spline axles when going to the spool... I'm getting mixed answers to this.

im @ a little over 600rwhp, 12 bolt, m6, 4.30 gears with the true trac, epp put it together for me, have gone wheels up and am pushing into the 9s and I haven't had any problems as of yet

im @ a little over 600rwhp, 12 bolt, m6, 4.30 gears with the true trac, epp put it together for me, have gone wheels up and am pushing into the 9s and I haven't had any problems as of yet

Thats nice but hope you dont have any wheel hop or you will end up like us. I had plenty of hard launches on mine but the first time I had some wheel hop this happened.

i had a 31 spline with the truetrack, all i did was buy the full spool "steel" from stange and my axles went right in.

rain...i wouldent worry at all.

no wheel hop for me, the shop that set up my backlash, still has the truetrack, i still havent gotten a chance to take a look at what broke

My truetrac is still working great behind 4000lb pig with over 900rwhp,however i am still considering going to a spool with some bigger splined axles

These thing brake when you floor it in turns f.ex drifting and sliding,if you do it in a straight line they are good

You are only loading one side of the true trac snails really so no wonder you can brake it

Mines been popping for a while on normal right turns only. doesnt do it when I turn left. Im gonna run the shit till it breaks. After that I dont know. spool or detroit locker.

I installed an auburn carbon disc diff in my 04 gmc 1/2 ton all stock and it pings and clunks around every corner unless you are hard on the gas. Sounds like same outcome with totally different diffs.
NOT SURE?

Wow and I thought that I was being picky with my rear end
I just installed my brand new Moser 12 bolt with 33 spline axles, 3:73 gears and a Truetrac..
And this thing howls, grinds, clunks at every speed, Rpm while accelerating and decelerating...
Everything from the brakes, driveshaft and ect has been checked it is definitely coming from the ring/pinion and differential and I did the break in procedure 4 times I ran it less than 10 miles then allowed it to cool an hour then repeated and my rear end hasnt even been raced yet...

My friends have track cars with 9 inch rears that have spools and competition gears that Make a hell of alot less noise than mine..
Everyone is also telling me that my rear is the most noisey 12 bolt they have ever heard..
I am waiting to call Texas=speed and Moser tomorrow because it feels like something is definitely up with this rear end..
And for the money that I spent on this rear end I am in no way impressed with quality of it..

Sounds like the problem I was having with my 10 bolt after swapping in 3.73s and forgetting the limited slip additive????

The Truetrac doesnt require a limited slip additive..

I did the entire suspension, and no I didn't have wheel hop, bmr extreme ta, boxed sfc, roded end ph, wolfe sb, and race only lca w/ relocation brackets. Personally if you have wheel hop you can't blame anything but yourself if something breaks in the rear, even a the strongest of rear ends will break with enough wheel hop, You need to set the car up so you don't have that problem.

I literally destroyed a Torsen T2R launching hard at the track. Helical carriers are just no good for hi HP hard launch clutch drop use. I researched the hell out of the TrueTrac last year and didnt find many failures at all since they went to the new 3 pinion design and i even bought one but never had time to install it in my car so I sold it to a buddy with a slower ride and now I'm seeing posts of TrueTrac failures pop up fairly often. That said I drove his car and loved the way the TrueTrac functioned and the Torsen in my car prior to grenading was also an AMAZING unit I loved the way it worked

BUT

Just not tough enough so now I'm back to the old tried and true and extremely TOUGH Ford Trac Loc.

FWIW when these units ( truetrac, torsen ) start making that popping sound when turning the days are numbered this is the tell so dont race or drive anywhere without knowing that you might need a tow home.

How does the Truetrac create "resistance". I have seen the gears and all and cant figure it out?

Its broken, btw, you could attempt a fluid flush to see, I have dusted 2 of these, if anyone wants to buy them, I sell it to them cheap! they are like 650 brand new, on a Moser 12 bolt.

Helical carriers dont create resistance thats the big advantage and why the road race crowd was ( before they started wearing out...) as I was saying WAS in love with them. They work just like an open carrier ( non posi ) until one wheel begins to spin which redirects power to the wheel with more traction. This is determined by a bias ratio that is designed into each specific unit.

In the case of Torsen units IIRC a stock application for a standard rear drive torsen the bias ratio is about 2:1 where the T2R is about 4:1

The concpet and technology behind them is brilliant and the function of them when they work is the best I have ever personally experienced its just a shame they dont seem to last all that well under racing conditions.

There is another type out there known as Black Gold that is a pretty serious looking piece although I nor anyone I personally know has ever run one.

If I wasn't so busy I'd design and build a helical unit out of better materials and charge whatever it needed but make sure it was the toughest thing possible. The Mark Williams approach to helical carriers if you will. Someone should do this...

Mark you reading any of this? LOL

Let me ask the question another way.

FTR I have a 9" Truetrac.
If I lift the rear wheels off the ground and with the tranny in 1st (T56), I can barely turn one rear wheel which will turn the opposite wheel in the other direction. It takes all the strength I have to do this but it will turn but has a lot of "resistance". How is this "resistance" created in the Trurtrac, what makes it so hard to turn compared to an open diff.

The little gears inside are tight and thats what makes it hard to spin. You think thats bad? Try and spin one wheel on a clutch type carrier or a T2R with the other on the ground its damn near impossible unless you use a huge breaker bar. If the load is insufficient then these units ( truetrac, torsen etc. ) they operate pretty much free as if there were no coupling action.

If those little gears inside spin one side of the truetrac too fast then they send power to the other side which couples them.

That helps. I could spin the Auburn in the 10 bolt a little as well. But the Truetrac is much harder.

The bigger the diff the bigger the internals the more bite your going to get. That said a 10 bolt Auburn when brand new should be very very hard to spin with the one wheel up method. The major downside to clutch type carriers is they wear out and dont really offer any resistance after a while. The Ford Trac Loc I am now praising is tough and all but the clutches inside the damn thing wear out every season or two and have to be replaced pretty often to keep any two wheel spinning action. One of the selling features of the truetrac and Torsen diffs are that there is no clutches or cones to wear out and they dont drag the inside wheel around corners which again is another huge reason the road course guys went GAGA for them. Sadly though for whatever reason or another they still wear out. I couldnt spin my Torsen at all with the wheel up test and it was almost spool'esque on the street the thing bit harder than a rattle snake woken from a nap... until it went boom that is

:barf:

How many of these True Trac problems are with the Ford 9" unit? I assume that some of you guys having problems are using 8.5", 12-Bolt, etc. Also does anyone have pictures of a broken unit? I am like Exotic, I have sold hundreds of these, and I heard my first complaint this morning from a customer who was reading through these forums.