View Full Version : Excessive Slack in drive train...

06-25-2007, 03:31 PM
I had my 03 in the Ford shop for warranty on the A/C a couple weeks ago. I asked them to check out the slack in the powertrain.. It looks like I can rotate the driveshaft atleast 3/16" back to front. Some slack is in ring and pinion and rest in the transmission I assume. It is not a problem unless you back off the power and give it power again, then you hear the clack pretty good. Anyway dealer told me it was within the clearance recommended by Ford. I have rebuilt 9" Ford rear ends years ago but not the 8.8. Is this normal or sound excessive??? My son-in-law's has some slack in his but not as much as mine.. He has 16,000 miles versus my 38,000 miles....

RF Cobra
06-25-2007, 05:40 PM
Slack in the drivetrain is typical on the 03/04 Cobras.

Typical word has been as long as it is within specs it is okay, just annoying at times like you mentioned.

06-25-2007, 06:07 PM
Yup, unfortunately if it's within spec, there is no reason to worry...just a clunky rear...

06-25-2007, 09:50 PM
Yeah mine did it too...So when I swapped to my solid rear end. I shimmed the rear end 4:10 gear tight so there isn't much backlash and still a perfect wear pattern.....:thumbsup: Very very little clunk :bounce:

06-26-2007, 04:37 PM
Same here ... everyone told me that it was normal and I have never had any problems. It will be louder for awhile if you change the bushings.

06-27-2007, 06:07 AM
Me too... You get used to it. The dealer told me that everyone that bought an 03 or 04 brings it back with the same complaint.

06-27-2007, 12:54 PM
Besides the clunk, do you get the rear end whine as well? Mine does it almost constantly. I've change the rear end fluid to Royal Purple, tightened everything up as best I can, with out over doing it, and still have the whinning, and occasional clunk.

Oh well. Build'em, beat'em , break'em....:thumbsup:

06-27-2007, 08:22 PM
i have it too

06-27-2007, 08:25 PM
No ... I do not have the whine at all. My clunk that was very noticable at first, and even more after the bushing change, seems non-existant now. My car only has 14,000 miles on it though. Mostly grocery stores and open track weekends.

07-01-2007, 09:00 AM
the slack in drive train was characteristic of both the 2001 and 2004 Cobra's but a bit more noticable in the 2004. I do not notice the clunk unless I am shifting into 5th or 6th at a relatively low speed (below 50mph).

Queston to Bignasty, Did you add friction modifier to the gear oil when you changed it? The only whine you shoud hear is from the supercharger or transmission. If the differential begins to sing a different tune, chances are it will be time for a new one. Either that or it is related to the tires or rear end alignment.