Found a surprise changing Ring & Pinion

[djtech]

I bought a Ford Racing 3.73 R&P to install. I also bought an IRS brace & new bushings. I wasn't expecting to buy any other parts until me and a friend opened the differential case. The spider gears in the track-lok are chipped bad. I'm guessing wheel hop caused this.

http://djtech.org/gallery/view_album.php?set_albumName=99-cobra-pumpkin

I'll be at Ford parts tomorrow at lunch to see how much replacing the spider gears is going to cost me. If it's $100 or more I'm going to get an Eaton.

 

[blk32V]

Damn, was your car making any noises with the gears looking like that? I would imagine so. I would go with the eaton no matter what the cost of the spider gears are imo. You obviously already have it apart, why take it apart again in the future to install the Eaton diff? I have the eaton 31 spline with Moser 31 spline axles.

 

[DirtySanchez]

As long as you've got it apart, you might want to consider swapping in a 31 spline carrier and upgrading to some 03 Cobra half shafts.

Also ... 3.73's with a T56? I'm guessing you have a roots or twin screw blower on the horizon?

 

[djtech]

I seen no ill effects while driving the car. I'm not even sure how long it has been like this since it's the first time I've opened up the diff.

I had my trak-lok rebuilt under warranty a couple years ago. Makes me wonder if the gears were chipped then.

I want to install an Eaton diff but I don't have the $$$ right now. I don't even have the $$$ for tires (plus have over $1,000 left on the credit card from the T56 conversion). Just generally a really bad time to upgrade.

I really want to upgrade though. I don't like putting the same replacement in a car when I break something like this. I'd rather get a strong unit. If I didn't have to buy new half-shafts with a 31 spline eaton it'd be an easier decision.

Spider gears - $99

Eaton - $300+
03 Carrier - $300+
03 half shafts - $300+ (each)
99 half shafts - just under $400 (each)

I'm still thinking about what I'm going to do... sigh

Damn, was your car making any noises with the gears looking like that? I would imagine so. I would go with the eaton no matter what the cost of the spider gears are imo. You obviously already have it apart, why take it apart again in the future to install the Eaton diff? I have the eaton 31 spline with Moser 31 spline axles.

 

[djtech]

I'd love to upgrade... see my reply to blk32V. I will get an Eaton instead of the 03 carrier though. I like Eaton design better and it doesn't cost much more.

No forced induction for a couple years. I want to build the motor with better internals first. Hopefully down the road I can get a turbo or two .

3.73 is the gear I decided on. Originally I was going to get 4.56's but changed my mind. My car isn't a drag car, it is a street machine. I want a decent (2500 or less) RPM in 6th at 80 MPH (I mean the speed limit! heh). I've got the 03 Cobra T56 so my 6th isn't as tall as the Viper spec. If I upgrade to the Viper Spec I"ll change to 4.56's or higher!

As long as you've got it apart, you might want to consider swapping in a 31 spline carrier and upgrading to some 03 Cobra half shafts.

Also ... 3.73's with a T56? I'm guessing you have a roots or twin screw blower on the horizon?

 

[djtech]

No upgrade...

Well I've decided to just get new spider gears. I'm getting part #2L1Z*4215*A which is a kit that contains all 4 spider gears, the pin and a few other misc pieces. $99.62 w/ tax. I might get new clutch packs too if they aren't that expensive.

I should have the parts tomorrow so hopefully I can finish the 3.73 install over the weekend

 

[yellow5.0cobra]

Find a cheap 99+ GT rear end and just swap the gears out.

Much cheaper than that crap... and no wheelhop(or AS MUCH wheelhop rather).

~$200 should get you a nice condition GT rear end...plus $110 for GOOD/EXCELLENT springs and $200 for GOOD/EXCELLENT shocks.

 

[djtech]

If I wanted a GT axle I would have bought an older Cobra or a GT. I like the IRS and won't be swapping it out. One of the reasons I got the 99 was the IRS (and I liked the looks a little more than the previous series).

Ford Trac-Lok & IRS aren't crap IMHO.

Find a cheap 99+ GT rear end and just swap the gears out.

Much cheaper than that crap... and no wheelhop(or AS MUCH wheelhop rather).

~$200 should get you a nice condition GT rear end...plus $110 for GOOD/EXCELLENT springs and $200 for GOOD/EXCELLENT shocks.

 

[Blk99SvtCobra]

i had the same problem

 

[djtech]

UPDATE

After making a pumpkin spreader I got the carrier out. It is broke too!

I guess that means new diff & half-shafts. No sense spending $300 on a carrier replacement from Ford or buying the same 28 spline if I'm going to buy a whole diff.

I purchased an 03 Cobra IRS assembly used. Figures I already drilled out my old IRS subframe bushings and pressed in the new ones. I guess I'll be pressing them out and doing the same on the new 03 assembly. At least it'll be easier doing the bushings with the entire IRS out of the car . I think I'm going to burn out those old rubber ones since they won't be right next to the gas tank.

I'm undecided about what to do with my 3.73 gear I bought. I'm either going to keep it or sell it (I think return is 15% restock fee). Now that I've got two IRS assembly's I think I'll put this 03 Cobra one in my car with all new bushings and over time as I save $$$ build up my 99 Cobra pumpkin with an aftermarket diff & 4.56 gears. Then I can just swap the pumpkin when I go the the track

 

[travis0712]

No doubt! I love the IRS and do not have wheel hop at all... I had a 99 GT, and a 2002 GB... I love my IRS..... night and day going through the turns... anyone can drive straight, but we like to turn left and right too IMHO

 

[SVTSTEEDA]

Damn, was your car making any noises with the gears looking like that? I would imagine so. I would go with the eaton no matter what the cost of the spider gears are imo. You obviously already have it apart, why take it apart again in the future to install the Eaton diff? I have the eaton 31 spline with Moser 31 spline axles.

what kind of noises would the car make? my car makes a binding or thumping sound from the diff. when i turn the car. also at low speeds (less than 5mph) you can hear a slow thump from underneath when you are driving. no sounds at normal speeds. what do you guys think it is? diff. or driveshaft most likely. any thoughts?

Good luck djtech with your car.

 

[djtech]

thx. it's gonna take me a week or more to get things back together because I want to repaint the 03 IRS I have. I also got some caliper paint so I'm going to do those too. Plus I've gotta put my new Optima yellow battery in the truck so that'll take some time.

About your symptoms... sounds like your Ford Trac-Lok needs to be rebuilt. There is a procedure on testing the trac-lok which involves putting pressure on the rear wheels (torque them against each other) to see when the clutch pack gives.

My Trac-Lok got rebuilt under warranty at like 10,000 miles. I had symptoms similar to yours.

what kind of noises would the car make? my car makes a binding or thumping sound from the diff. when i turn the car. also at low speeds (less than 5mph) you can hear a slow thump from underneath when you are driving. no sounds at normal speeds. what do you guys think it is? diff. or driveshaft most likely. any thoughts?

Good luck djtech with your car.

 

[SVTSTEEDA]

thanks for the info. i actually have an auburn diff. that Steeda installed along with other goodies when the vehicle was new. i bought the car used and knew it had a few issues. once i save up some money i can have the issues resolved.

 

[djtech]

I hear Auburn's are nice. The Pro series is supposed to be strong & durable.

Do your symptoms usually occur while turning & going slow? I'd think that'd be a diff issue. I don't think Auburn's are rebuildable.

If you do need a new diff I'd suggest the torsen unit. That's what I want to buy when I hit the lottery. They work with Ford 8.8's w/ and w/o IRS. $500 tho!

thanks for the info. i actually have an auburn diff. that Steeda installed along with other goodies when the vehicle was new. i bought the car used and knew it had a few issues. once i save up some money i can have the issues resolved.

 

[SVTSTEEDA]

yeah it makes the sound at very low speeds and when turning. i just don't have the money to do anything right now. hopefully this summer i can take the vehicle in and have someone look it over. i just rebuilt the supercharger a few months ago and that sucked up all my reserve. does the diff. ever get to the point that it can be a safety issue? i mean is it hazardous to drive it or will it just not perform like it should because it is worn out? sorry for all the questions, my knowledge is poor.

 

[Blk99SvtCobra]

if you dont think you have wheelhop try some new gears\
my car was jumping like an olympic gold medalest
since then ive put in poly bushings and a brace and my car sits on the floor like never before the wheels just spin and grab no bounce no clunking sounds
BEAUTIFULL