Hi, new to the site and am amazed at the sheer volume of info available. Thanks to all.
Well here goes my problem and am hoping someone may have seen or heard of this before.
Bought a used clean 2003 Cobra. Drove it for about 1000 miles. One day as i'm coming to a slow left into my street, i downshift to second and when i let out clutch the engine just revs and car does not accelerate. I pull over immediately to investigate. Everything sounds normal and as i let out clutch in first the car does not move. I notice though the speedo shows speed. So i am already thinking its not clutch. Tow it to my mechanics shop and here is what he finds... all the bolts holding the ring gear to the carrier in the differential have backed out and are sitting in the dif. Gears are shot, cover is cracked, housing is scored...
The gears are 4.10 so we quickly formulate an opinion as to what happened. Previous owner must have had the 4.10's installed and some idiot did not loctite the bolts and/or did not torque the bolts properly.
With new parts ordered and a 3.73 ratio selected the dif is rebuilt. All parts are cleaned and bolts are loctited and torqued.(this guy has probably done over 100 gear swaps for mustang guys). All is well and car runs great. No gear noise and the mileage is a little better too.
Car is put away for winter with about 500 miles on the rebuilt dif.
Fast forward 5 months and the Cobra is pulled out of hibernation. I put maybe another 500 miles on it when one day i take an exit of the freeway and am just coasting in 6th. Suddenly i feel a violent lurch as if the car wants to stop. I pull over to investigate in a large parking lot.(Deja vu at this point). Car makes funny noise from dif in reverse and coast, but ok under acceleration. Luckily my mechanic is only about 5 miles from my location and i was able to get it there without any more incident.
He finally is able to get to it a week later and here is what we find when he removes the irs dif....
Two bolts have backed right out, fallen into housing and the rest of the bolts have all backed out about 3/16" (Deja vu). This time there is major damage to the carrier, gears are shot, housing is scored beyond repair, cover is cracked...
Hence the reason for my post in the classifieds "looking to buy a complete dif. or even a housing and cover.
I would really appreciate all yours help if anyone has heard of this problem.
My only worries are I will replace the dif, and have the same problem again.
We checked the driveshaft for runout-ok
We checked the half shafts-ok
I have had the car up to 140mph and never ever had any vibrations coming from the rear end.
My only other solution is to drill and lockwire the bolt heads this time.
Please help.:idea:
Well here goes my problem and am hoping someone may have seen or heard of this before.
Bought a used clean 2003 Cobra. Drove it for about 1000 miles. One day as i'm coming to a slow left into my street, i downshift to second and when i let out clutch the engine just revs and car does not accelerate. I pull over immediately to investigate. Everything sounds normal and as i let out clutch in first the car does not move. I notice though the speedo shows speed. So i am already thinking its not clutch. Tow it to my mechanics shop and here is what he finds... all the bolts holding the ring gear to the carrier in the differential have backed out and are sitting in the dif. Gears are shot, cover is cracked, housing is scored...
The gears are 4.10 so we quickly formulate an opinion as to what happened. Previous owner must have had the 4.10's installed and some idiot did not loctite the bolts and/or did not torque the bolts properly.
With new parts ordered and a 3.73 ratio selected the dif is rebuilt. All parts are cleaned and bolts are loctited and torqued.(this guy has probably done over 100 gear swaps for mustang guys). All is well and car runs great. No gear noise and the mileage is a little better too.
Car is put away for winter with about 500 miles on the rebuilt dif.
Fast forward 5 months and the Cobra is pulled out of hibernation. I put maybe another 500 miles on it when one day i take an exit of the freeway and am just coasting in 6th. Suddenly i feel a violent lurch as if the car wants to stop. I pull over to investigate in a large parking lot.(Deja vu at this point). Car makes funny noise from dif in reverse and coast, but ok under acceleration. Luckily my mechanic is only about 5 miles from my location and i was able to get it there without any more incident.
He finally is able to get to it a week later and here is what we find when he removes the irs dif....
Two bolts have backed right out, fallen into housing and the rest of the bolts have all backed out about 3/16" (Deja vu). This time there is major damage to the carrier, gears are shot, housing is scored beyond repair, cover is cracked...
Hence the reason for my post in the classifieds "looking to buy a complete dif. or even a housing and cover.
I would really appreciate all yours help if anyone has heard of this problem.
My only worries are I will replace the dif, and have the same problem again.
We checked the driveshaft for runout-ok
We checked the half shafts-ok
I have had the car up to 140mph and never ever had any vibrations coming from the rear end.
My only other solution is to drill and lockwire the bolt heads this time.
Please help.:idea:
Last edited:
