8.8 TrueTrac Problems?

[Stage 4.6]

Very glad I reviewed this thread, I am considering rebuilding my rear end over the winter and haven't decided which diff to go with?

After reading I am not to confident with the Trutrac, I have used the Eaton 31 spline on my old 01 roush and didn't have any luck with it either, I end up buying a new cobra rear diff from AM

Anyone else have some experience with the Torsen diffs, noise, reliability issues?

 

[Boaisy]

Reviving an old thread - just because I want to warn prospective buyers

I bought an Eaton TruTrac to go in a 2003 Mach 1 with 60K miles on it. Old Trac-loc was worn out. I had read that the Trutrac was supposed to be smooth and quiet - NOT TRUE.

I'm sure they work great for off-road and drag racing, where you dont care about noise, but on the street it is noisy!
Whenever I put it in neutral and let it freewheel, like when approaching a stop, my car sounds like a tank coming down the road. It has a clunking noise coming out of the rear, an dit does not stop until under 5mph. It is not the bearings - I know what bad bearings sound like, and it was opened up and checked twice more for loose parts or bad bearing. This noise goes away when you get above 40mph. It also clunks a lot and I can hear it crunching and engaging in turns. At first in a sharp turn, it always spins the inside wheel until it locks up, which I hate.

I tried synth and conventional oils - it was actually quieter with the synthetic, but not by much.

I finally went to an Eaton Limited Slip differential with the 400lb springs (much stronger and better holding than the stock Ford diff). It is dead quiet and handles better than it ever did with the stock Ford Trac-lok. This is a conventional limited slip with better design than stock.

My car no longer sounds like it is powered by marbles!

This is the same exact noise i get with mine too ever since it was installed about a year ago. Even had the shop reinspect the rear end for loose parts. Tried Torco fluid at first, then switched to Lucas (80-90w Dino on both). Lucas is quieter, but any kind of coasting you just hear a rattle/clunking like a tank from the rear. Quiets down after 5mph. If the driveline is engaged, the noise goes away. It is definitely making me consider a Boss Torsen now, which I probably should have done in the first place. I'm sure the Eaton is a durable unit, but that noise has to go.

EDIT:

Digging around, it seems the Truetrac does the same in other units as well. Mostly with Mustang's and Astro's. Apparently Eaton said it is a natural backlash of the diff when no load is on it.

Called tech support again today. The guy I got today was aware of the noise problem. He said it's more prevalent with Mustangs and Astro Vans.
He said when coasting, that the worm gears move (he said tumble) in the case causing the clicking sound.

A first time driver of this differential will notice some differences compared to driving with a conventional differential.

Turning: An occasional snapping/metallic sound may be heard due to component dis-engagement and re-engagement; transfer of torque from both wheels to one wheel (and back to both wheels) may be noticeable in the feel of steering.

Drive-to-Coast: A metallic sound may be heard due to the normal backlash built into the unit.

Slippery Roads: Vehicles equipped with traction differentials are inherently more sensitive to side slip. Use caution when changing speed on slippery or unstable surfaces; decelerate, but DO NOT APPLY THE BRAKE.

 

[CCS86]

I am really surprised to hear these issues with the Trutrack. Right before I installed it in my '12 GT, I stumbled on this thread, and I was a little worried.

After a couple days driving around on the Trutrack, I could not be happier with it! I have driven around with the windows down and have not heard a single peep out of it. The Trutrack is almost invisible in its operation, smoothly sending torque to the wheel with the most traction. Even the worse case, a sharp right hand corner in the wet, couldn't even come close to spinning up the inside tire.

I wonder whether the issues people are having, are installation related, or a quality control issue. After some testimonials of their installations, I'm leaning towards the latter. As an engineer for a CNC manufacturing company, I can't say that I like seeing "made in Taiwan" on parts I am using, but for an assembly like this to cost $480 to your door, that's likely what you get. Their design is really pretty simple, with the crux of it being well cut gear tooth profiles and fairly narrow production tolerances between the mating parts of the assembly. I stuck my fingers in the unit before installing to check out the operation, and it took quite a bit of effort to move, with no perceptible lash. Maybe those with noise simply have a looser fit between mating gears, or to the case itself.

I didn't change rear gears, so I didn't have to mess with the pinion. I had planned on just matching the factory backlash, but found it to be about 0.0125", which is just out of spec. The shims included in the Motive install kit are complete garbage; mainly the thicker 0.100" shims. They are essentially saddle shaped, and could act like a spring washer, rather than a rigid shim. Also, the thinner ones included are 0.010", 0.015", and 0.020" (also sporting nice burrs on one side from the stamping process). That only gives you the ability to make changes of 0.005" or more; just not a fine enough increment to dial things in nicely. I was finally able to build a shim stack that put my backlash at 0.010" (after a lot of wet sanding!)

I started out with 85w140 Valvoline High Performance (dino), but am considering switching over to Amsoil Severe Gear down the road, after break-in; assuming things stay quiet.

If Eaton wants to outsource manufacturing to Taiwan in order to hit a certain price point and profit margin, that is up to them. But, a smart company would internally test the units to ensure quality, or at the very least, stand behind the product, happily exchanging a noisy unit with apologies (after ruling out install error). It sounds like about half of us are very happy with the Trutrack, and the other half are pissed (and rightly so), after receiving what we would call an "escape" at my company.

I think you guys with issues should kindly refuse to accept "normal" as an answer from Eaton. Rather than lash out at them (bad joke, haha), lay out the facts and ask them to do right by you as a customer. If anyone wants an eye proof reading a letter to Eaton, I'm happy to help.

 

[keith89]

Yeah the answer i got from Eaton was it's "normal slack in the worm gears". As I've said before, my unit is quiet when on the power and cornering but when i'm switching between load no load and decel, the whole driveshaft bounces back and forth as if my ring and pinion has too much backlash. I've taken my rear cover off and rotated my driveshaft and the ring and pinion both moved to take up the slack, indicating its slack in the inner workings of the differential. If it wasn't such a hassle to tear it down, i'd swap it back out for the stock unit. I stopped doing track days in the car anyway.

 

[GodStang]

Been running mine for around 4 years now still dead quiet. I did swap out gears and have DSS lvl 5s.

 

[Stage 4.6]

Where's the best place to get a deal on the Trutrack?

 

[CCS86]

$479 shipped from Summit

 

[oldstv]

I am currently having two rears built. Both will have the Wavetracs this time around. I was told they are dead quiet and hope their right. Both cars are over 700 hp and cutting 1.4s through autos. We shall see.

 

[Stage 4.6]

$479 shipped from Summit

Thanks!

 

[Weather Man]

I am currently having two rears built. Both will have the Wavetracs this time around. I was told they are dead quiet and hope their right. Both cars are over 700 hp and cutting 1.4s through autos. We shall see.

Hop on S197 and search wavetrac. They have issues. My local trans shop was working a swap with me on a built axle. The axle he had was out of a supersnake with a blown wavetrac. The axles are extremely hard to get out when it lets go.

 

[oldstv]

I am sure they all have some issue. I have blown an Eaton and a Auburn "on different cars" so I might as well try the Wavetrac. Got my fingers crossed!

 

[P49Y-CY]

I am sure they all have some issue. I have blown an Eaton and a Auburn "on different cars" so I might as well try the Wavetrac. Got my fingers crossed!

lifetime warranty on the wavetrac. if you can break that thing you are a baller! lol

 

[Tractionless1]

Thanks!

Got my Detroit TT on Amazon cheaper.

 

[CCS86]

It has been listed at $479 for a while on Amazon. They charge me tax in TX, so Summit was cheaper for me.

You could set up a camelcamelcamel alert in case it dips.

 

[Tractionless1]

It has been listed at $479 for a while on Amazon. They charge me tax in TX, so Summit was cheaper for me.

You could set up a camelcamelcamel alert in case it dips.

Camel alert WTF is that? I purchased mine years ago when it was in the high $300's, as with everything prices go up and salaries don't.

BTW, mee too!

 

[CCS86]

Camel alert WTF is that? I purchased mine years ago when it was in the high $300's, as with everything prices go up and salaries don't.

BTW, mee too!

It tracks amazon prices

 

[Tractionless1]

It tracks amazon prices

Cool thanks!

 

[whitedevil95]

I got mine about a month ago from Summit for $479 with free shipping. And it got to my house in 1 freaking day. I havent had my SRA built yet. I had ready nothing but great reviews about this diff until i just stumbled upon this thread. Im sure it sucks more with an IRS because all the sound goes straight into the sub frame of the car and is much louder than on an SRA. But im a little nervous now.

 

[TonyG2]

I'm reviving this old thread again to let people know that today my trutrac noise disappeared. From day 1 when it was installed, it sounded like someone was shaking a box of marbles whenever I let off the gas and decelerated.

Two things were modified, so I don't know which one was responsible (or if they both were):

(1) pinion seal was replaced -maybe it was the pinion seal itself or one of the other things that gets touched during this job

(2) UCAs replaced -I'm not drag racing as much in my "old age," so I switched from hard core UCAs (Baseline) with heim joint/spherical bushings, to more normal UCAs (Steeda) with their 3-piece poly bushings. I know that the spherical bushings in the Baseline UCAs were not the source of the noise, b/c I had them when I had my old tracloc and there was no noise. The noise started when the truetrac was installed.

I suppose that it's possible that the solid metal bushings were transmitting the noise from the diff. Now, the noise is absorbed by the softer bushings. But it is a dramatic effect. I can't believe how quiet the car is now. I can hear the radio, and I don't sounds like a Sherman tank coming down the road (as someone posted above). I can enjoy driving the car on the street again.

 

[Skud]

Might as well throw in an update as well..

I haven't driven the car much this summer, but the TrueTrac still works well. I don't hear any noise at all and it's smooth around the corners. Based on my experiences I highly recommend.

Riley