detroit truetrac in irs

what fluid should I use with this
the oe spec, or somethin else

thanks
I'll also be running a diff cooler with this if that makes any difference

Let us know how that unit works for you. I am considering either Detroit or Torsen.

John

ive heard good things about both, the detroit was cheaper, and supposedly the newer torsens are having some problems from cost cutting that torsen refuses to own up to
the detroit is also a bit beefier i believe

Have you run it yet? That will be my mid-summer upgrade. The stocker is killing me when exiting turns. Slips like crazy. Clutches are probably completely shot.

John

the car is tucked away for winter and this was just something i did while its sitting in the garage
hope to have the results of this upgrade along with many others in next summer
should be a beast:banana:

I use Royal Purple Max Gear 75w140 full syn in mine. I am not running a cooler so I just change it once a year.

I drilled and tapped a drain hole in the very bottom of the hsng to make changes easier.

I absolutely LOVE my True Trac! I am able to put more power down and sooner than I could before on corner exit.

It is also much easier to----> pull out from a stop sign and turn/merge into on coming traffic, with severe camber change, in the rain, or with other traction limitations.

To keep this in perspective my OE diff clutches had not expired yet.
It's that good!

OE fill for my car was 75w140 full syn anyway so going to an organic 80w90 was not an option in my mind.
Though I believe it is compatible with the True Trac.

..

I just had the TrueTrac installed and won't get the car on a track for another month but I'm surprised at how much better it rotates into turns. Shocked is a better word.

On the street on my usual back road with severe off camber, uphill/downhill 150 degree turns section, the car just hooks and goes.

No more spinning the inside wheel/wheel hop/modulate the throttle to prevent major drama episodes. Just smooth, feed in more throttle traction. I seriously didn't expect the TrueTrac to make that much of a difference versus the stock OEM clutch pak.

I'm stoked to get the car on track and really put it through its paces but if the street behavior is the same on track, I'm going to be fired up in a big way.

I went through the same research everyone else did and decided not to invest in the Torsen due to the recent reliability problems vs. the TrueTrac. The TrueTrac had issues too but was redesigned and seems to be stable.

I'm running OEM fluid in it for now (less friction modifier since its not needed). This was really an exceeding expectations upgrade for me. I really wish I did this upgrade when I bought my car. All these years with the Ford limited slip was wasting a lot of time.

John

Fast99Snake said:

what fluid should I use with this
the oe spec, or somethin else

thanks
I'll also be running a diff cooler with this if that makes any difference

Click to expand...

I talked to a tech representative from Eaton ( the company that makes the tru trac) and he specifically advised against using synthetic gear oil since the synthetic lube lowers the torque bias of the true trac and may cause noise. I personally would be concerned about running mineral oil in the IRS diff because the IRS can run hot. I would be curious to hear from Those of you with a True trac who run synthetic lube.

cobraracer46 said:

I talked to a tech representative from Eaton ( the company that makes the tru trac) and he specifically advised against using synthetic gear oil since the synthetic lube lowers the torque bias of the true trac and may cause noise. I personally would be concerned about running mineral oil in the IRS diff because the IRS can run hot. I would be curious to hear from Those of you with a True trac who run synthetic lube.

Click to expand...

There is so little fluid in these IRS diffs it makes me nervous thinking about the durability of the ring and pinion and bearings if I were to run organic 80w90. Even on the street these things get WICKED HOT!

I do not have a diff cooler so I run full syn 75w140 RP.
I have no noises, and no one wheel peel.

Would the bias be better with organic?

Apparently so, if they say so.

The gears in the diff can and will eventually wear out. They will last longer than clutches but friction is friction, and some day they will be spent.
I'll put up with little less bias and run a lube that I know will help make things last longer.

If I was racing, I might do things differently, but I'm not.:-D

Here is the link to the Truetrac Owner's Manual

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

It specifically states under lubrication that it was designed to operate in the lubricant recommended by the vehicle/axle manufacturer. I would therefore conclude that Jimmy is correct. I cannot remember for sure but I believe I used 75w140 full syn when I put the Truetrac in my Lightning as well and have experienced no problems either, of course I don't drive mine all that often. I do drive it hard when I am driving it though, as a reference point I replaced the factory diff after only 6000 miles and the truetrac has served me well for the remaining 12000 I have put on the truck since I made the change.

Jimmysidecarr said:

The gears in the diff can and will eventually wear out. They will last longer than clutches but friction is friction, and some day they will be spent.

Click to expand...

Jimmy, Given the red highlighting, I presume you're talking about the TrueTrac gears versus the ring and pinion gears right? There is a differential as in the "pumpkin" and then there's the TrueTrac.

Heck, I wouldn't mind having enough track miles to enjoy the problem of replacing it if that's the case. :rolling:

Mine isn't an IRS, but I've had my Truetrac for two years now. Be sure NOT to use friction modifier with your gear oil. You don't need it on a clutchless diff.

After reading this thread, my mind is made up, I'm going with the true trac! To me, it seems that the true trac offers all the performance of a torsen for less money. Another fact that steered me toward the tru trac is that it can live a happy life in a high HP drag car while the Torsen is not recommended for drag racing.:burnout:

Torque biased differentials ROCK in the snow

Maynor said:

Jimmy, Given the red highlighting, I presume you're talking about the TrueTrac gears versus the ring and pinion gears right? There is a differential as in the "pumpkin" and then there's the TrueTrac.

Heck, I wouldn't mind having enough track miles to enjoy the problem of replacing it if that's the case. :rolling:

Click to expand...

Yea I meant the TrueTrac gears not the R&P. I would love to have enough track miles to wear one out too!:rockon: :beer:

I suspect they will be throwing dirt on my pine box before it ever needs replacing.

Anyone has experience and Axle breaking with one of these. 1. Can it witstand the shock of the axle breaking and 2 what happens to the car when it does break one axle. ? I would think this reacts almost like a posi or a spool and steers the car hard right or left.

I called Eaton/Detroit and the tech told me to use only petroleum based, non-synthetic 80w90 (I believe that was the weight) gear oil.

SKMCOBRA said:

I called Eaton/Detroit and the tech told me to use only petroleum based, non-synthetic 80w90 (I believe that was the weight) gear oil.

Click to expand...

I believe the tech you talked to may not know our application. (full of crap is what I wanted to say!)

The instructions clearly state use OE fill, which is 75W140 full synthetic.


NO WAY I WOULD RUN ORGANIC 80W90!

OOPS! I see you have 97 cobra-->Are you running a stick axle still? The OP was talking about an IRS fill.

..

Jimmysidecarr said:

I believe the tech you talked to may not know our application. (full of crap is what I wanted to say!)

The instructions clearly state use OE fill, which is 75W140 full synthetic.


NO WAY I WOULD RUN ORGANIC 80W90!

OOPS! I see you have 97 cobra-->Are you running a stick axle still? The OP was talking about an IRS fill.

..

Click to expand...

Do the mustand stick axles run a different lube than the IRS? I realize its a different axle (9.75") but the stick axle in my Lightning still calls for 75W140 full synthetic from the factory which is what I used with my True-Trac without any problems.

BlackBolt9 said:

Do the mustand stick axles run a different lube than the IRS? I realize its a different axle (9.75") but the stick axle in my Lightning still calls for 75W140 full synthetic from the factory which is what I used with my True-Trac without any problems.

Click to expand...

I think the switch to synthetic is driven more by model year.:shrug:

I'm not sure when exactly they started synth but 97 probably was organic.
My 99 Navi calls for synth. and it has the 9.75 stick axle too.