Eaton LSD

Post by **Grayson** » Mon Nov 10, 2008 6:29 pm

I'm organizing a second Eaton LSD Group Purchase if anyone wants in. Details are in the Sponsor/Vendor section, linked here:

viewtopic.php?t=13062&sid=803e35be6e92e ... 04b57329db

Ray · Post by **Ray** » Tue Nov 11, 2008 9:08 am

Grayson,

I'm going to try to return the eaton i bought locally from advance auto to get in on your deal instead. I'll email you. I'd be interested in the full kit with the service to to the output shafts as well.

DSPXR4ti · Post by **DSPXR4ti** » Tue Nov 22, 2011 11:28 pm

Hello All,

Just to let you know but I have been running my EATON LSD for 7 years with no ill effect, with drag race starts and all the slow turns in autocross I think thats a great record.

Ben

Post by **espacef1fan** » Wed Nov 23, 2011 10:00 am

There still seems to be some confusion on my part about the ring gear.

Do the bolt holes on the 3.64 ring gear line up on the Eaton? Or not?

DSPXR4ti · Post by **DSPXR4ti** » Wed Nov 23, 2011 10:55 am

espacef1fan wrote:There still seems to be some confusion on my part about the ring gear.

Do the bolt holes on the 3.64 ring gear line up on the Eaton? Or not?

They are a little off set but no mods to the to the EATON or ring gear is necessary.

Ben

Post by **Grayson** » Wed Nov 23, 2011 12:48 pm

I've never noticed the ring gear bolts and the Eaton bolt pattern being "a little off". They're both on the exact same bolt circle. Now, the lateral location of the differential within the rear axle assembly is a little off, if that's what you mean. Of course, you can either shim between the ring gear and the differential (poor method) or use offset outer bearing races in the side adjusters (perfect method) to accomodate that.

For anyone interested, you don't need to grind the case in order to install an Eaton or a Detroit either. However, if you want to avoid grinding, you have to press the bearing cones on the differential after the differential is installed in the rear axle case - you can't install the cones first. Grinding isn't a big deal though. There are a few hundred Eatons and Detroits that have been distributed to Merkur and Sierra owners over the past few years, 99% of them are in clearanced cases, and nobody has ever broken a rear axle with an Eaton or Detroit installed.

Also, for anyone interested, Eatons and Detroits have a $30 mail-in rebate for units purchased before January 1, 2012. I've been thinking of offering a full build service for the first time, and maybe doing that on top of the Eaton rebate would work well for Merkur owners. I'll get through Thanksgiving first though.

Post by **espacef1fan** » Wed Nov 23, 2011 2:19 pm

Im aware of the ring gear spacers. Was just worried about hole alignment.

Post by **DPDISXR4Ti** » Wed Nov 23, 2011 2:44 pm

espacef1fan wrote:Was just worried about hole alignment.

I wonder if it's got to do with the fact that the "GM 7.5" is actually 7.625" vs. the 7.5" of the Euro Ford ring gear? Maybe if the through-holes are large enough it becomes a non-issue? I've got no hands-on experience with building one of these hybrids, so just going by what I recall reading. Feel free to shoot the messenger if I've got things entirely or even partially wrong.

Post by **hEaT** » Wed Nov 23, 2011 8:25 pm

I don't recall the holes being off when Ray did his a few years ago...but it was a few years ago and it was FREEZING.

Post by **Grayson** » Fri Nov 25, 2011 8:30 pm

There is no mismatch between the bolt pattern of the Eaton differential and the Merkur/Sierra ring gear.

mecatech · Post by **mecatech** » Mon Jan 09, 2012 8:12 am

hi

many question

i'm interrested about race eaton diff.

i have a sierra cosworth 3dr and i upgrade the lsd diff, but i can't upgrade more ...

more over une ring and gear are very expansive for this car.

if i will buy a lsd diff eaton or detroit, do i have many choice for ring and gear ( to buy) ?
or do i must keep mine

many thanks

Post by **Grayson** » Mon Jan 09, 2012 4:50 pm

The ring and pinion choices for your 7.5" rear axle have absolutely nothing to do with the differential you choose to install. So, whether you install and Eaton, a Detroit, a Quaife, a Gripper, or whatever, the ring and pinion options are the same. There are five ratios available between 3.36:1 and 4.44:1 that I know of, and cost & availability varies with each one.

mecatech · Post by **mecatech** » Tue Feb 21, 2012 11:40 am

hi

are the eaton or detroit LSD have 23 spline ? like diff 7.5" cosworth ?

thanks

Post by **Grayson** » Tue Feb 21, 2012 3:16 pm

The non-Cosworth 7.5", Cosworth 7.5", Eaton and Detroit all have the same spline diameter and count. If you check out this installation procedure you can see how the various combinations all go together:

http://www.mc2racing.com/tech/20081104a/index.html

twin turbo · Post by **twin turbo** » Thu Sep 06, 2018 5:20 pm

Hello. Is flanges/shafts possible to get that fit straight in? I have Cosworth... I know i Can mod and make IT work with the original, but wondering if new custom directly fit is avilable.

Know its a old tread, just asking, since found a diff in storage missing flanges, and have a few 7.5 diffs missing LSD...

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