Jag diff noise(es)

[Chris D]

At the risk of starting something , let me ask the question publicly that seems to get aired often in Cobra conversations? How much gear noise and backlash should we get from a Jag' diff as used in many Cobra kits? Furthermore, will the impact of using a Power Lok diff make any great difference over an open diff.

Before the responses come rolling in, my question does have a bit of technology behind it as I recently had a power lok diff re-geared with new 3.54:1 gears (Dana 44's) and replaced all that could be repalced without being silly.

It still has some backlash and I reckon it's from the internal splines; magnified by the rigid mounting of the diff housing. Gear and bearing noise is minimal. Word of warning. make sure the nuts used on the output flanges - where the disks fit - are NOT nylocks. Use metal locks as the nylon melts under hard braking. This bit of advice is from the Jag' manual.

Finally, the Power Lok centres on these diffs have cast steel spider gear carriers which do break. These carriers, arranged as a cross, are the cams sitting in V blocks that lock and unlock the clutch packs. The interlocking cast steel carriers (2 piece) are becoming difficult to get now and any that are out there are very worn. I had a toolmaker make me a set from tool steel and anyone is welcome to have a look if interested.

I also have detailed service and instructions on these locking diffs. They are actually American from Thornton - first used in Jeeps in the 50's, I think.

Now tell me about the noise levels please.

Cheers
Chris

[David Hodgson]

Chris, I don't know how much noise there "should" be but you are right, it is exacerbated by the solid mounting of the diff housing and even more magnified when I fitted the single hoop roll bar which has the inner mount socket welded right next to the diff top mount. When I finish the rollbar I will fill it with expanding foam to try and deaden the ring.
I guess thats why vehicle manufacturers refer to suspension bushes and engine mounts as "insulators".

[Rebel1]

Chris, without jumping all over your post and like you, I am interested in answers to your questions.

However, I've also been told that if using the powerlok diff ( which I am) then the locking mechanism should be loosened( if thats the right term) to slip at a lower torque rating.

The reasoning being that if the diff is set to lock at x force in a 5000lb jag, then in a cobra at say 2500lbs, that force should be less or the diff will act like a locker.

Could be all BS but I'd like to add that to your questions.

Cheers

[Chris D]

http://www.vernco.com/powr-lok/