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LSD: Eaton Detroit Truetrac 913A477 Technical only

50184 Views 115 Replies 50 Participants Last post by  kazuo
I would like this thread to stay focused on the installation of an Eaton Truetrac 913A477 differential. If you contribute, please do not speculate about the merits of LSD, or weather one should use a locker or other type differential. I would like this post only to list descriptions, P/Ns, supporting kits and results of forum members who have installed, or are about to install a Torsen type differential. (I read all the postings to date and they are all filled with conjectures, opinions and side-bar discussions, that make if difficult for anyone to quickly determine what they need to install LSD in their transit.)

Ford 9.75" Eaton Detroit TrueTrac | 34 Spline - 2017 street price - $539.99
- P/N 913A477
- Requires: 1.370" diameter 34 spline axles.
- Type LSD: Torsen
- Torque Bias Ratio: 3.5:1
- Cover = 12 bolt
- Pinion nut: 1-1/8

- Fits all OEM Transit gear ratios

This differential is installed the most in 2011-2017 Ford F150s with 9.75 rear ends.

Other rebuild kits that may be needed for installation, depending on mileage of van.
Crush sleeve and Master bearing kit
Example: Yukon Gear Bearing kit BK F9.75-D

To help stiffen up the pumpkin, F-150 forums recommend that you replace the steel cover with an aluminum girdle cover: Such as a Yukon YP C3-F9.75 - Street price around $200.
(This type of cover has bolts in the cover that secure to the bearing caps to add additional stiffiness.)

There is also an "Axle Crush Sleeve Eliminator Kit" available. (Anyone use one of these?)

Enjoy.
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When you had your TrueTrac installed were you told that it would void your warranty? We would like one installed on our 2019 T350 but the differential shop we spoke with said they wouldn't do it because it would void the warranty.
My understanding is that any aftermarket part/s installed on your vehicle that is/are not OEM part/s will not be covered under your factory warrenty. If the dealer can prove that the replacement parts you install cause other parts on the vehicle to fail, then everything associated with the faillure will not be covered by the warrently.

It is a very low probability that a LSD differential will cause any other part failures on the van, (unless you are doing something abusive to the van outside its operational design envelope.) Since Ford offers their clucth plate version of LSD as an option, installing a Truetrac is a more durable and robust solution than the OEM LSD.

Installing a "Locker" or "E-Locker" has a higher probability of stressing parts on the van then a LSD. Primarily because this mean the driver might take the van off-road on road conditions that the van was not designed for.
 
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Also, with a very rare drivetrain warranty issue, they would have to discover that you got a better differential than they supplied which is doubtful unless you say "gee do you think this is on account of the locker I put in there?" Then they'd have to prove it caused the problem. It is your van, get what you want to enjoy it and don't look back!
 

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When you had your TrueTrac installed were you told that it would void your warranty? We would like one installed on our 2019 T350 but the differential shop we spoke with said they wouldn't do it because it would void the warranty.
Its not going to void your warranty. If your aftermarket part breaks, Ford is (of course) not going to cover it. If your aftermarket part breaks and doing so, breaks some of Ford's parts, Ford isn't going to cover that either. Get the truetrac installed. You will love it in snowy weather. Good luck.
 

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I had a True Trac installed yesterday at Jaws Gear and Axle in Sacramento. $1100 OTD. They used Shell Spirax HD Gear Oil, which is one brand recommended by Eaton. Seems really smooth so far, but have not had it off the pavement yet. Hope to test it out soon.
I had a True Trac installed yesterday at Jaws Gear and Axle in Sacramento. $1100 OTD. They used Shell Spirax HD Gear Oil, which is one brand recommended by Eaton. Seems really smooth so far, but have not had it off the pavement yet. Hope to test it out soon.
I want it I need it
 

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I wonder if it's OK to use this? Gear Competition 75W-140 - Motul as I have tons left over from my Subaru..
For a number of reasons, it shouldn’t be optimal: contains friction modifiers, synthetic (which I question whether that is really a bad thing), and the hot viscosity (“thick” at 170). But then, I’m trying to figure out where you heard this stuff would be good for a Subaru??? Maybe it’s the secret sauce we’ve all been looking for.


2015 Tall, Medium Length, Cargo, 3.5EB, pretty generic-looking, DIY camper
 

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For a number of reasons, it shouldn’t be optimal: contains friction modifiers, synthetic (which I question whether that is really a bad thing), and the hot viscosity (“thick” at 170). But then, I’m trying to figure out where you heard this stuff would be good for a Subaru??? Maybe it’s the secret sauce we’ve all been looking for.


2015 Tall, Medium Length, Cargo, 3.5EB, pretty generic-looking, DIY camper
I ran this on my built RallyX build.. and no it should not come with friction modifiers.. that's the reason I suggested.. it is also ester based.. was great in my 550whp subie.. i assume it would be fine in the transit? Just asking really... and yes Motul is probably the best name in RallyX.. just ask Dirtfish what they use.. etc...
 

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For anyone wanting to attempt this install themselves, I installed one of these a few months ago. It really wasn’t that bad. Took me about 6 hours. You of course need some specialized tools to measure backlash and a legit vice for torquing down the pinion ring bolts. I used the shim kit from Yukon. Here’s the install prior to replacing the diff cover...
141545
 

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Mrjmathew, do you recall what fluid you used? (Fluid seems to be a fairly hot topic on these).

For anyone else who installed a Tru-trac, AND who used dino lube instead of synthetic, how often are you changing the fluid out?


2015 Tall, Medium Length, Cargo, 3.5EB, pretty generic-looking, DIY camper
 

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Mrjmathew, do you recall what fluid you used? (Fluid seems to be a fairly hot topic on these).

For anyone else who installed a Tru-trac, AND who used dino lube instead of synthetic, how often are you changing the fluid out?


2015 Tall, Medium Length, Cargo, 3.5EB, pretty generic-looking, DIY camper
Lucas 80W90 GL5
 

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Thank you for this write up. I have decided to go with the TrueTrac. Now, I have to find a shop near me that is able to do install this at a reasonable price.

Is it better to let the shop source the parts, or should I bring the parts in.
I would imagine it would be better for them to get the parts. I feel it's like brining your eggs to the diner, and they might not like it.
 

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I want to say thanks, too, for this thread. I just had a TrueTrac added, as part of a major drivetrain repair (which I will detail elsewhere, with photos). The info here took the work out of having shops write estimates. The Ford dealership service center won out, due to flakiness of an independent shop. The service manager was trying to help me save money (and land the job) and suggested I buy the TrueTrac up front, so that he would not have to add markup. I got it for $703, delivered, from Summit Racing.
 

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I had a True Trac installed yesterday at Jaws Gear and Axle in Sacramento. $1100 OTD. They used Shell Spirax HD Gear Oil, which is one brand recommended by Eaton. Seems really smooth so far, but have not had it off the pavement yet. Hope to test it out soon.
Did you have it re-geared too or are you on the stock ratio?

Thanks for the reference on price, seems affordable.
 

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I just picked up a 2015 Ecoboost HR with 150,000 miles. Has anyone done this on a high mileage vehicle yet?

Wondering if I should go ahead and also replace the pinion bearings and seal while I'm in there.

I was already thinking to replace outer bearings and carrier bearings on the axel.
 

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Actually I think I could test this out....
Let me see about going back out to the same spot and do the same climb in 2 wheel drive with rear TruTrac vs 4 wheel drive Fr/Rr TruTrac.
Sounds like fun to me :)
A couple years late on this one, but I did this exact test in my Bronco. Two years ago while hunting, I got stuck in 4wd going through a particularly rough spot on the trial. Fast forward to last year. After having front and rear truetracs installed, I was able to easily crawl through that same trail section in 2wd with zero tire slippage. I had left in 2wd just as a test. Same tires, same trail, very different result. Street manners are exactly the same as OEM LSD. Def worth the upgrade.
 
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