Help Diagnosing Damaged Differential

[Juggernaut]

I know you said it was making noise before you changed fluid but if you replace it with another Trac loc unit make sure to use friction modifier.
A Trac-loc can click and pop without friction modifier. Ford and spicer both make a great modifier additive.
I have better luck with non synthetic diff fluid and adding modifier on clutch pack diffs. Also do slow figure 8s after fluid change to work fluid between clutches.
Personally I like Trac locs but that's just me. I wouldn't get hung up between them if you find a low mileage unit.

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[tdstuart]

I know you said it was making noise before you changed fluid but if you replace it with another Trac loc unit make sure to use friction modifier.
A Trac-loc can click and pop without friction modifier. Ford and spicer both make a great modifier additive.
I have better luck with non synthetic diff fluid and adding modifier on clutch pack diffs. Also do slow figure 8s after fluid change to work fluid between clutches.
Personally I like Trac locs but that's just me. I wouldn't get hung up between them if you find a low mileage unit.

Sounds good thank you for the advice!

 

[Jaymar]

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.

Anybody who does a custom tune for the car can accommodate the ECM change, Whipple included. BCM can be done with Forescan, that is the lesser of the two as it should not affect drivability from what I understand. I could be wrong but Forescan is easy so why not?

Torsen is better at putting power down while the diff is in differential action, like coming out of a corner. Trac-loc is basically an open diff with clutches between the two axles. It's brutally simple and works great when the axels should be at the same speed like a drag race. The only time you should exceed it's capabilities launching are with extreme traction and horsepower. Once you get up there you're using a spool or locker anyway. Strength? There are a few other components past the transmission that will break long before the differential unit itself will so I'd call it insignificant.

If you have a "slap" when you put it in gear and reverse you have some slack in the drivetrain doing that. If you have checked the axels as others have mentioned, and you're sure the diff is solidly installed on those bushings then you have backlash in the diff somewhere be it from a destroyed pinion bearing or worse. In fact, if the diff was moving around on the previous bushings already you may as well just count that pinion bearing as likely toast.

 

[tdstuart]

Here is a video of the noise. I am shifting from drive to reverse and back to drive.


You can hear me move the shifter and then hear the wonderful crunching and clicking.

Going to order a new differential unit today or tomorrow. Today when leaving my house and turning right the car made a high-pitched metallic scraping sound also coming from the differential area. I am certain it's crying to be put down after abuse. And I want to hopefully swap it before it fully gives out.

I found a good deal on a low mileage 18 3.15 ratio unit. The 18+ flage will work with my 15 driveshaft since its an auto right?

Also any opinions on if I should get a different gear ratio? Car is currently fbo e85 cammed. Stock converter still, need to save money for that. Eventually will go boost but probably not for a while as I need to be in a better financial situation. Iv'e seen some n/a guys who were drag racing say that swaping the differential ratio didn't help much. I roll race the car more then I drag race the car.

Thank you guys for all the help!

 

[NeverSatisfied]

I have all the tools and know how and I’d still buy a complete diff and swap it. By the time you buy gears, bearings, borrow all the tools, do the work, bugger the pinion seal on install, reinstall, find drips on your floor, do the whole job over again, etc,

you’ll save yourself a ton of time and frustration swapping it out for a low mile replacement.

 

[tdstuart]

Update: it was the halfshafts.

Changed the differential (bought a whole new carrier) and noise was still there. So I got some halfshafts and that solved it.

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