Rear End LSD on 2010 Crown Vic

[HankHill]

Well all, my LSD in my 2010 police package rear end is throwing off metal (was told by dealer its clutch material) , diff oil looks like mercury.. Has anyone here ever replaced a LSD before, and how hard is it to accomplish? Where would you purchase an LSD? I've looked at car-part.com, Rock Auto, and some other places that I googled.

A few Questions About Rear LSD Assemblies:

1. Does the ring gear attach to the unit? Meaning can I reuse the gears and replace just the unit?

2. How hard is it to replace the unit, meaning how hard is it to set the diff up? How hard is it to set the clearances, contact preload of the gears?

3. My rear axle assembly only has 90k on it, and I know how I burnt out the clutches, I was stuck on a highway covered with an inch of ice.. I was flooring it to dig through ice and get me moving, very dumb, live and learn..

4. Would you replace the entire rear axle assembly with a reman unit, a yard axle, or just the LSD. If I just do the LSD, should I buy new gears too?

5. Does anyone have an idea how much labor would be to do each option?

I am leaning toward a new lsd unit, I really don't want a used one, too much of a gamble on its condition...

Any advice would be greatly appreciated!

Thanks to all! Happy New Year!!

 

[bdcardinal]

Are the clutches worn? If so you can buy new clutches and rebuild the unit without having to pop the ring gear off. Ford Performance has a carbon fiber clutch kit whch is really nice and should work on your car that should have 31 spline axles.

 

[Rob_Roy]

You can rebuild the limited slip carrier with a new clutch pack. The parts are about $100 and the job is not bad at all. If you are not comfortable doing it, as the dealer and a local indy shop for a quotes. Plan on doing a quick gear oil change to help get things cleaned up.

 

[Kuato]

+1 on replacing the clutch pack. Easy, cheap and as designed.

 

[bdcardinal]

M-4700-C is the kit you want. Then just get some gear oil. You will have to soak the clutches in friction modifier before installing. The Ford p/n is XL-3.

 

[Falcon_LS]

Alternatively you could do as I did and get a Torsen T-2, and not have to worry about clutches again.

 

[bdcardinal]

Alternatively you could do as I did and get a Torsen T-2, and not have to worry about clutches again.

Obviously the correct answer. The extra money and time spent setting up the diff is worth it.

 

[HankHill]

Alternatively you could do as I did and get a Torsen T-2, and not have to worry about clutches again.

Thanks for the idea Falcon_LS! So when you installed the Torsen, was there any differences you noticed at all? Did you change the gears? How about any bearings?

 

[Falcon_LS]

Thanks for the idea Falcon_LS! So when you installed the Torsen, was there any differences you noticed at all? Did you change the gears? How about any bearings?

I was upgrading the rear gears, so I literally swapped out everything including the bearings. Mine has 28 splines, so it was extremely difficult to find the correct LSD at the time, but your 2010 will have 31 splines, which is much easier to find. I also went ahead and installed a new aluminum GT500 differential cover while I was at it. Slightly higher capacity, and it has drain and fill holes built in, which makes servicing a lot easier.

As far as differences go; absolutely! It's works by biasing torque, so it's MUCH more stable around corners now.

 

[Asterix]

Any differential rebuild is not for the faint-of-heart. Getting all clearances, preload, and backlash set right is critical. It takes some special tools, a press, and patience.

Surely your ring and pinion are not anywhere close to worn out. New bearings could be in order, but inspect them first. Definitely replace all the seals.

I suggest finding an off-road shop as they rebuild differentials all the time, so are very good at it. The mechanics at any dealership will not have that much experience, if any. My preference is a clutch LSD ("posi") because you can adjust the action with the fluid.

 

[bdcardinal]

You would need new carrier bearings when switching to a Torsen, or any other differential, as those are pressed onto the differential. If you just rebuild your existing Trac-lok you will not need to change bearings.

 

[HankHill]

You would need new carrier bearings when switching to a Torsen, or any other differential, as those are pressed onto the differential. If you just rebuild your existing Trac-lok you will not need to change bearings.

Are the carrier bearings included into an 8.8 differential rebuild kit? I'm having them change all the bearings on the axle. Do I need special carrier bearings that the Torsen needs?

 

[HankHill]

Any differential rebuild is not for the faint-of-heart. Getting all clearances, preload, and backlash set right is critical. It takes some special tools, a press, and patience.

Surely your ring and pinion are not anywhere close to worn out. New bearings could be in order, but inspect them first. Definitely replace all the seals.

I suggest finding an off-road shop as they rebuild differentials all the time, so are very good at it. The mechanics at any dealership will not have that much experience, if any. My preference is a clutch LSD ("posi") because you can adjust the action with the fluid.

Thanks for the tip on the off-road shop, I'll call them today... I'm going to do the pinion and ring gear because there is slop in the axle (or the driveshaft U-JOINTS) The axle does put out a decent amount of noise, especially at slow speeds and high speeds also. Had my friend drive the car and I was in the trunk, yeah they're pretty loud compared to other axles on my trucks and cars.

 

[bdcardinal]

Are the carrier bearings included into an 8.8 differential rebuild kit? I'm having them change all the bearings on the axle. Do I need special carrier bearings that the Torsen needs?

I would think so. Ford doesn't have kits on the service side, so we just look up all the parts individually. XW4Z-4221-AA is the bearing and D9AZ-4222-A is the race.

 

[KJH]

Like others have said, ford clutch type LSD are cheap as hell to rebuild, I would go that route. Not sure switching to a Torsen is worth the extra cost and hassle when the option of replacing the clutch packs is so cheap, easy and effective. You ford guys are lucky, coming from an import background, clutch type LSD from the factory is almost unheard of, and aftermarket units cost 2-4x as much to rebuild in parts alone, to be honest considering replacing it with a whole new torsen unit seems unnecessary and a bit crazy. But I am a clutch type LSD fanboy.
If the installation is done correctly, that slop you talk about should go away with proper settings they do during install, Ive never seen someone replace a ring and pinion unless it was obviously damaged ( usually during track driving) or to change the final drive ratio.

Also, an obvious but crucial tip from the drifting crowd, who absolutely torture diffs: changing the gear oil with really high quality stuff once every year or two will greatly improve the performance and longevity of every part in your diff. Easier than changing transmission fluid. and is relatively more beneficial.

 

[DuckRyder]

It is an 8.8 track loc putting that into the tube of you should get you like 3 weeks of videos on it.

1) yes

2) its not that hard if you have the tools to replace the entire unit some patience and ability to understand the 3 weeks of you tube videos. its even easier to rebuild the clutch pack, but "throwing metal" isn't a good sign.

3) wasn't a question

4) if i was in spend money mode or it was not rebuildable, i would put a Eaton True Trac in my existing axle. if i could save the track loc i would put the FRPP/SVO/Motorsport (whatever they are calling themselves this week) kit in it. Ring gear inspection is warranted, if its serviceable and the ratio suits you no need to replace.

5) wouldn't surprise me for a shop to want 4-5 hours to O/H don't have a book in fornt of me though.

Summit Racing is your best bet for in stock.

Oh, I lost count of how many Auburns i replaced in F-Bodies back in the day.

 

[t1snwrbrdr12]

Your 31 spline 8.8 will more than serve your needs. I put one through 550 plus hp (at the wheels) in a drag car, abused the crap out of it on slicks with a stick shift in front of it and a puck style race clutch.

 

[HankHill]

It is an 8.8 track loc putting that into the tube of you should get you like 3 weeks of videos on it.

1) yes

2) its not that hard if you have the tools to replace the entire unit some patience and ability to understand the 3 weeks of you tube videos. its even easier to rebuild the clutch pack, but "throwing metal" isn't a good sign.

3) wasn't a question

4) if i was in spend money mode or it was not rebuildable, i would put a Eaton True Trac in my existing axle. if i could save the track loc i would put the FRPP/SVO/Motorsport (whatever they are calling themselves this week) kit in it. Ring gear inspection is warranted, if its serviceable and the ratio suits you no need to replace.

5) wouldn't surprise me for a shop to want 4-5 hours to O/H don't have a book in fornt of me though.

Summit Racing is your best bet for in stock.

Oh, I lost count of how many Auburns i replaced in F-Bodies back in the day.

Good old F-Bodies.. I had an '87 5.0 IROC.. That was the biggest chit show I've ever owned.. It only looked cool, and leaked around the T-Tops...

I'm replacing the gears because I can, its going to be labor wise cheaper than any other point this car will ever see. I can get a Ford Performance 3.27 gear set for $160, why not do it? I have never had a Posi go bad, or have the oil, which I changed in June, look like mercury before. I know what I did to kill the unit. It's 100% my fault, I think..
It has 96k on it, with not a spec of rust.. If you live in the rust belt, you would know how unbelievable that is for a 12 year old P71 Vic.. I would like to take it up to over 300k, and I will be driving all over the US with it soon. I want that piece of mind so I don't have to worry about it. I get super paranoid about stuff, which I admit is my OCB. With all that metal in the oil, I think something other than clutch was damaged. Hopefully the ring and pinion replacement will get rid of that whine, and slop from coasting to giving it gas with a clunk. Its a nice clunk for sure, and its coming from the diff, I could feel it while I had my hand on the diff housing. I'll also be replacing the Diff cover to one that has drain and fill plugs on it. I can find a non-ford racing cover somewhere I think.. The Ford racing cover is about $270, and hopefully I can find a cheaper one.

So, I will be putting in a Torsen T-2 unit, changing all the bearings, and seals on the axel.

If the diff carrier is not damaged, I'll take a crack at replacing the clutches. Put it up for sale in the CV forum, if anyone wants it, they can have it with or without the clutches replaced.. Maybe I can recover some cost there.

Thanks for all information and advice. I'll take pictures of Carrier before its removed, and the gears.. And a close up picture of the clutch surfaces while out of the vehicle l. I'll also take a picture with the Torsen installed.



Thanks for all the replies, the education, and the help!

 

[t1snwrbrdr12]

Usually the clutches wear so bad that the spider gears get slop between them and eventually wear the teeth. Our fleet of trucks typically make it to the point they don’t drive anymore, but our drivers are a special breed. Ford also sells the spider gear kit. But if you’ve decided to go a different differential route, that solves that.

 

[SwampSurvivor]

The parts aren't going to be a lot, but the labor cost difference between replacing the worn out limited slip and a complete rebuild is going to be significant.

You're looking at rebuilding the limited slip for $300 or $400 at a shop to doing a $1400 axle rebuild.

Offroad shop is a good suggestion. They should be familiar with 8.8s.