Broke the front mounts on my differential tonight at the track

[lxh89]

So took a trip up to Northstar Dragway in Denton to test out my new Baer drag brakes. I only got one good pass before all hell broke loose. On my second pass, car hooked insanely hard then around the end of the 60 it sounded like Id broken the driveshaft.

Got towed home and put up the car on jack stands and found this - front mounts were sheared completely! The other thing I noticed, the pinion flange where the driveshaft connects slung some kind of grease. Not sure if the driveshaft is fubarred but I'm definitely gonna need a new differential housing.

I'd heard the differential bushings could lead to this so can't say I'm very surprised but didn't think it would have at the 700rwhp level. I was thinking these cars making 850+ were doing this kind of damage.

Tony

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[z06psi]

This isn't the first auto diff to break. Get a stock manual one as they are iron.

The grease from the driveshaft is coming from under the cover where it bolts into the flange.

 

[lxh89]

This isn't the first auto diff to break. Get a stock manual one as they are iron.

The grease from the driveshaft is coming from under the cover where it bolts into the flange.

Yeah, I ordered a 3.55 diff and an automatic flange to convert it.

Thanks

 

[lxh89]

Got the differential pulled out and looks like the end of the drive shaft that connects to the diff flange has some kind of universal ball joint. Well, it's totally fubar and spins. That explains all the grease getting ejected from it. It also explains why the car wouldn't move in forward or reverse.

So new driveshaft now too...

I think the pinion bearing took some of the brunt too because there's considerable end play when I pull/push the pinion inside the diff housing. It feels kinda sloppy upon turning. Everything else looks fine.

Tony

 

[GuardEcoBeast]

Wow! Lots of carnage. Sucks man

 

[Dominant1]

Well at least you know your making good power. Broken parts are a part of the game. Good thing is everything can be fixed!!

 

[Cobra Jet]

What does it look like inside the diff - have you checked yet?

I wonder if the ring/pinion sheared teeth...

 

[BMR Tech]

Welcome to the club.

 

[lxh89]

What does it look like inside the diff - have you checked yet?

I wonder if the ring/pinion sheared teeth...

I didn't open the housing. The gears move free. I think it's just tore up the pinion bearing based on the end play slop.

It usually takes a lot more to break an 8.8 gear set. Spider gears typically break first then the resulting metal pieces get caught between the pinion and ring gear causing more damage.

Tony

 

[Dominant1]

Ford performance iron differential with 3:55 traction lock gears $899..

 

[lxh89]

Don wood ford has them for 790.54. Thats where i got mine. Ordered last saturday and got it yesterday.

Really nice folks to deal with too.

Fordracingpartsbydonwood.com

 

[lxh89]

Got everything back together tonight. I got the last piece today, a shaftmaster's driveshaft.

I got it in, took the car for a spin and first thing I noticed was a clicking noise coming from the left side of the vehicle. Took it back home, pulled the rear wheels, pulled the axle nuts and re-torqued them. Put it all back together and clicking still there on left side.

So took it for a highway run and get vibration at 60mph. Got it up to 100 and the vibration is ridiculous. So I'll try re-clocking the driveshaft. Kind of annoying but seems to be a thing with the s550 driveshafts.

I ordered a stocker off ebay to have as a last resort in case I have to RMA this one.

The good news is, the new differential with the 3.55s is smooth as silk with zero whine.

Tony

 

[Jeff_oddo]

Did you have diff lockout bushings or just stock ones?

 

[lxh89]

Diff lockout bushings...steeda

 

[Jeff_oddo]

Upgraded hardware? I have the Steeda ones with the BMR upgraded hardware.

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