Help Diagnosing Damaged Differential

[tdstuart]

Until you diagnosis what is causing the noise there is no real advice/direction any of us can provide to help you determine how to proceed further with fixing your car. Removing the rear housing cover will give you a closer look at the ring and pinion gear teeth and spider gears as well. You should also be able to see possibly what is moving/worn that could be causing the noise.

If you don't want to tear into the housing to determine the issue, then just replace the whole unit with used/new pumpkin.

BD

I’ll check to see if I can pull the cover off without removing the diff.

If I could find a whole used pumpkin at a good price I would

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[ice445]

I’ll check to see if I can pull the cover off without removing the diff.

If I could find a whole used pumpkin at a good price I would

Check local salvage yards. Not the self pull it kind, but the ones that part out newer stuff. https://www.car-part.com/ sorted by distance is usually my go to for stuff like this.

 

[IPOGT]

I'm not trying to poop on your abilities, 30 years ago I was in a cold garage with a 302 taken completely apart wondering if I was in over my head too. We all have to start somewhere. With that experience plus the intervening years, I can tell you that you don't want to tackle a differential. The tools to do it properly will cost you more than having the job done. There are shortcuts around some of those tools but those require the experience that comes with having done that job many times before. If you knew enough about the differential to figure it out, you'd know mostly what those noises are that you are hearing. Again, nothing against you, those things come with experience that you will gain along the way.

Unless the Mustang is a project car and you have the disposable income to do the job multiple times if you go wrong then take it in to have it done. There will be plenty of maintenance jobs on this car to get you that experience as well. If you want to lean the ins and outs of more complicated jobs in a consequence free environment, pick up an old Mustang or Ranger as a second car you can wail on in your free time. It's always good to have an ugly Ranger around that you just don't care about.

SPECIALTY WORK. Even my 30 year master Ford technician will NOT touch differentials.

 

[Tucker80]

The only budget friendly option is to do it correctly the 1st time, not DIY a hack job by just tossing parts at a problem that still isn't diagnosed.

If the OP works at a Ford dealership I'm not sure why they can't properly diagnose, but will be there to assist with the repair once the internet tells them what's wrong..

 

[tdstuart]

The only budget friendly option is to do it correctly the 1st time, not DIY a hack job by just tossing parts at a problem that still isn't diagnosed.

If the OP works at a Ford dealership I'm not sure why they can't properly diagnose, but will be there to assist with the repair once the internet tells them what's wrong..

Because I don’t want to spend $1000+ on labor.

Why spend $1000+ on labor plus hundreds on parts and wait weeks when I could just spend $700 and get a whole new carrier?

And why is it a diy hack job? Worst case it breaks and I learn something

 

[Jaymar]

Because I don’t want to spend $1000+ on labor.

Why spend $1000+ on labor plus hundreds on parts and wait weeks when I could just spend $700 and get a whole new carrier?

And why is it a diy hack job? Worst case it breaks and I learn something

Then replace the carrier if you can get the whole diff for $700. What's the problem here? You seem to think there is a $40 bearing at AutoZone that you can slap in based on next to no diagnosis to magic things up. There isn't. Everyone else here is trying to convey to you the precision and complexity of the device you've decided to teach yourself on. Your car so your choice but if I had to ride with you I'd make sure I was wearing comfortable shoes.

 

[tdstuart]

Then replace the carrier if you can get the whole diff for $700. What's the problem here? You seem to think there is a $40 bearing at AutoZone that you can slap in based on next to no diagnosis to magic things up. There isn't. Everyone else here is trying to convey to you the precision and complexity of the device you've decided to teach yourself on. Your car so your choice but if I had to ride with you I'd make sure I was wearing comfortable shoes.

No but I can get a differential or ring/pinion gear for a few hundred.

I rebuilt my engine myself, I’ve done all my mods and all my repairs myself, I did the differential bushings myself.

Instead of offering actual advice some of you are dead set on bashing me to get me to let someone else do it. I understand they are complex, hence me not instantly knowing everything about them. At the same time instead of repeatedly saying it’s complex don’t fuck it up, why don’t you tell me which parts are tricky and what things I should reasonably be able to do. If I mess it up I mess it up, I have no problem with messing something up as I am learning.

My first engine rebuild I learned several things; ring seal and break in is very important, and don’t use apex headstuds.

And my car has never broken down on me

 

[tdstuart]

Check local salvage yards. Not the self pull it kind, but the ones that part out newer stuff. https://www.car-part.com/ sorted by distance is usually my go to for stuff like this.

Only 3 showed up on there. Found some carriers on eBay for a decent price that I am looking at. Trying to get a 3.55 ratio 18+ so I can get the Torsen differential and not have to deal with the trac-loc failure. As far as I understand all the 3.55 in the 18+ are torsen

I’ve looked at some parts places that are local but have never had luck finding any s550 mustang parts

 

[Jaymar]

Only 3 showed up on there. Found some carriers on eBay for a decent price that I am looking at. Trying to get a 3.55 ratio 18+ so I can get the Torsen differential and not have to deal with the trac-loc failure. As far as I understand all the 3.55 in the 18+ are torsen

I’ve looked at some parts places that are local but have never had luck finding any s550 mustang parts

3.55 is not Torsen except for maybe some HPP Ecoboost or maybe some auto PP1 5.0 cars. But, if you do change ratio you have to change programming in the BCM AND the ECM tune, it isn't just one place. 3.73 is the only diff guaranteed to be Torsen, but don't count out the normal trac-loc either, it is the carbon clutch pack similar to the Terminator so it doesn't suck either.

At the least, you will be replacing bearings and likely also the ring and pinion upon inspection. Diff clutch and spiders need inspection but I'd bet on ok. That puts you on the hook for at least setting backlash, possibly pinion depth. Both precision operations that set the location of the pinion and ring in 3D space. There isn't just some measuring you can do with a feeler gauge like a spark plug. You have to make precision measurements in the 10^-3 inch level referencing to standard points. Then you'll need to run in on some marker dye and know how to read the pattern to make final adjustments/checks.

Nobody is bashing you, you just don't seem to realize that everyone else here knows what you're up against and we realize that you don't. We all started where you are, if young me was in your shoes I'd offer the same advice to him. I started pulling engines in a garage, went on to make a professional career out of it and now I work on machines that measure success in Angstroms. It takes confidence to believe in your abilities and dive into those things but if I didn't know where to draw the line I could cause an accident with a price tag well beyond a car. Believe it or not, measured ambition is more of a skill than blind ambition . You have to want to get in and learn things just as much as you need to know when to listen and pass.

 

[tdstuart]

3.55 is not Torsen except for maybe some HPP Ecoboost or maybe some auto PP1 5.0 cars. But, if you do change ratio you have to change programming in the BCM AND the ECM tune, it isn't just one place. 3.73 is the only diff guaranteed to be Torsen, but don't count out the normal trac-loc either, it is the carbon clutch pack similar to the Terminator so it doesn't suck either.

At the least, you will be replacing bearings and likely also the ring and pinion upon inspection. Diff clutch and spiders need inspection but I'd bet on ok. That puts you on the hook for at least setting backlash, possibly pinion depth. Both precision operations that set the location of the pinion and ring in 3D space. There isn't just some measuring you can do with a feeler gauge like a spark plug. You have to make precision measurements in the 10^-3 inch level referencing to standard points. Then you'll need to run in on some marker dye and know how to read the pattern to make final adjustments/checks.

Nobody is bashing you, you just don't seem to realize that everyone else here knows what you're up against and we realize that you don't. We all started where you are, if young me was in your shoes I'd offer the same advice to him. I started pulling engines in a garage, went on to make a professional career out of it and now I work on machines that measure success in Angstroms. It takes confidence to believe in your abilities and dive into those things but if I didn't know where to draw the line I could cause an accident with a price tag well beyond a car. Believe it or not, measured ambition is more of a skill than blind ambition . You have to want to get in and learn things just as much as you need to know when to listen and pass.

The reason I am looking into the torsen is because it seems to be agreed upon that it’s stronger than the trac loc and I don’t want to have to deal with differential problems in another 30k miles.

I don’t think I would want to go to a 3.73 as I eventually want to boost the car and I struggle so much with traction as it is.

So everyone who swaps gear ratios has to set backlash and pinion depth? It seemed to me like it was a fairly common thing people do

 

[Jaymar]

The reason I am looking into the torsen is because it seems to be agreed upon that it’s stronger than the trac loc and I don’t want to have to deal with differential problems in another 30k miles.

I don’t think I would want to go to a 3.73 as I eventually want to boost the car and I struggle so much with traction as it is.

So everyone who swaps gear ratios has to set backlash and pinion depth? It seemed to me like it was a fairly common thing people do

It's a common thing to pay someone else to do. At an average dealership shop, there are probably 1-2 techs that can do the job. Independent shops vary depending on their focus. Going to a specialty 4wd shop increases your chances as they see more than average. Still, there are tuning considerations to make. Look that one up here as it's been discussed many times before, just realize that the BCM and ECM operate independently so changes to one don't carry to the other.

Torsen isn't any tougher than trac-loc, there are other things that will give long before the differential unit does anyway. If you're really having a hard time putting it down, you can preload the trac-loc with more clutches to tighten it up but in all honesty, if you are really at that point you're getting into locker or spool territory and you aren't getting there on any streetable blown Coyote. Save that money for OPGs and crank supports.

 

[CorvZ061]

I’m reading your initial posts, and I’m curious how you’ve decided the differential is the cause of your noise? Clicking/popping while turning is more likely to be the axles, than the differential itself. You also mention some clicking after you park the car, if the car isn’t moving neither is the differential, there’s no noise coming from it. Are you sure the sludge you found wasn’t clutch material and gear oil mixed? Trac-loc’s are clutch based, and if you’re abusing it like you claim I can see the clutches getting destroyed. And the clutches can be replaced without having to worry about setting up a differential all over.

I’ve built a lot of engines, I’ve done a few differential’s too. Never done a 8.8 in particular, but I do know on a 9” and a GM 12 bolt that it’s a totally different ball game than rebuilding an engine.

 

[tdstuart]

Still, there are tuning considerations to make. Look that one up here as it's been discussed many times before, just realize that the BCM and ECM operate independently so changes to one don't carry to the other.

Yes I’ve heard a little about this. Is the whipple tool the only option currently? I wonder if

Torsen isn't any tougher than trac-loc, there are other things that will give long before the differential unit does anyway. If you're really having a hard time putting it down, you can preload the trac-loc with more clutches to tighten it up but in all honesty, if you are really at that point you're getting into locker or spool territory and you aren't getting there on any streetable blown Coyote. Save that money for OPGs and crank supports.

So you don’t think the torsen is any beefier than the trac-loc? From what I read on here people seem to think the torsen holds up a lot better.

I think traction is more suspension and tire. I need a converter and a better tire and probably some adjustable coilovers.

I also already have opg. If I go boost I would preferably go twin turbo and maybe try to fab up my own if I can find some smaller welding projects to try first. If not probably an ESS kit.

 

[tdstuart]

I’m reading your initial posts, and I’m curious how you’ve decided the differential is the cause of your noise? Clicking/popping while turning is more likely to be the axles, than the differential itself. You also mention some clicking after you park the car, if the car isn’t moving neither is the differential, there’s no noise coming from it. Are you sure the sludge you found wasn’t clutch material and gear oil mixed? Trac-loc’s are clutch based, and if you’re abusing it like you claim I can see the clutches getting destroyed. And the clutches can be replaced without having to worry about setting up a differential all over.

No clicking or popping when turning. The clicking when parked sounds a lot like the popping of the exhaust cooling down that almost all cars make but much louder and coming from the carrier. Nothing I can think of around that area that would be making noise.

Initially, I thought the noises I was getting when shifting from drive to reverse and reverse to drive was just the differential carrier slopping left and right in the bushing sleeves as the bushings were badly worn. I pulled the rear subframe and replaced the carrier bushings and subframe bushings with polyurethane bushings. When the car was running again it still had the same clicking noises when shifting from drive to reverse and reverse to drive. Probably because of the stiffer bushings I could now also hear noises when downshifting and stopping. I also want to note when you go from drive to reverse and reverse to drive you can visibly see the suspension load and unload and it usually makes multiple clicks.

I had the halfshafts out and they looked fine, I had the drive shaft disconnected from the carrier flange and it also looked fine.

After the car was back together I jacked the car up to get the rear wheels off the ground. I moved each wheel back and forth a little bit. You could hear a similar clicking coming from the differential carrier. The movement did not cause the driveshaft to start turning. If I turned the wheels back and forth more the driveshaft would start to turn but I did not hear any additional clicking noises. This happened with both wheels. Both wheel bearings seem to be fine and did not have any noticeable play when tugging on the wheel.

Because of all of these things, it is my belief that there is some slop in the gears either with the differential or the ring and pinion gears.

I’ve built a lot of engines, I’ve done a few differential’s too. Never done a 8.8 in particular, but I do know on a 9” and a GM 12 bolt that it’s a totally different ball game than rebuilding an engine.

Thank you for the insight

 

[ice445]

Yes I’ve heard a little about this. Is the whipple tool the only option currently? I wonder if



So you don’t think the torsen is any beefier than the trac-loc? From what I read on here people seem to think the torsen holds up a lot better.

I think traction is more suspension and tire. I need a converter and a better tire and probably some adjustable coilovers.

I also already have opg. If I go boost I would preferably go twin turbo and maybe try to fab up my own if I can find some smaller welding projects to try first. If not probably an ESS kit.

I think the general consensus is the trak lok is better if you're drag racing or doing straight line stuff, whereas the torsen is better for track use or canyon carving. Trak Lok will hold up for a long time unless you're always introducing huge wheel speed differences, like doing burnouts or powering hard out of corners.

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