Grinding rear end - bad differential or other problem?

[greg schroeder]

Originally Posted by edmonds007

Thanks for the feedback guys.
Greg, was the $2000 tag for the parts and labor? Just wondering if you did any of the work yourself.

I'm all for upgrading if I have to replace anything so I really appreciate that you included the vendors for the parts you used.

Any other recommendations from the viewing audience???

I did the removal and install of half shafts and rear end as I wanted to learn how it works and clean everything in there while I was at it. It was a reasonably smooth learning curve with the club cobra and internet at my finger tips and the helpful shops which the parts came from. For me this is part of making the hobby fun. I just like to know what happened when something occurs on my car.

The Detroit Truetrac was 450 dollars however I did pay labor to have it take the position of the limited slip at SVC Motorsports in Scottsdale, AZ. It still looks like a Ford 8.8 on the outside, but the guts are just different now. SVC is an extremely detailed shop that digs into detail. I wanted to be certain gear tolerances were perfect and they let me see the job being performed.

The Detroit Truetrac is superior out of corners and in a straight line without doubt. If you do a search on the internet the opinion is about 99% the same. The new half shafts are stronger than the original type that came on the Superformacne with the Ford 8.8 rear end, but not everyone needs to go stronger.

If you make the change you'll have the option to go to 31 spine parts from 28, but it will cost a bit more as you'll need to change the wheel bearing with splines on the outside. You should change the inside bearing anyway. The drive shaft shop would call it their stage 5 instead of stage 2. Actual Ford parts are stronger than the Superformance parts, but the center bar needs to be the correct length. I went with the 28 spline again at the advice of the drive shaft shop saying it would be fine for a car and driver of 2550 lbs.

If you do a search on the forums you find people have used the Superformance half shafts without failure while others have not. I'd estimate much of this has to do with actual usable power on the road, how sticky their tires are, how much side wall flex the tires have and how they start from a stopped position. Engine HP is irrelevant as there are way too many variables by the time it's in the car. Trap speed at the strip or even time would provide a better estimate of strength necessity.

Here's a drag race calculator to estimate usable power. The trap speed calculation would be most useful as times vary greatly while speed only varies slightly at the end of the 1/4.

http://www.pro-system.com/calc.html