Kirkham diff

[rsk289]

Can anyone give me some advice on Kirkham diffs in a 289, please?

My Kirkham diff has been in the car for about 4,000 miles now and has performed faultlessly. However I was on a run this weekend, but after pulling off the highway a loud screeching metallic noise became evident from somewhere in the rear of the car. I've checked everything over and can find no concerns with wheel bearing, brakes (no stones stuck etc.), inteference from cables etc.

In checking the driveshafts, I discovered that there is very noticeable up and down movement of the diff output shafts. I can move the right side one up and down about ⅛", and the left side one a bit less. I don't know if this right or not, but I've checked a spare Jag diff I have and that has no movement at all. There is a sort of star wheel adjuster in the casing which looks as if it can adjust the bearing and is held in position by a small locking plate.

Can anyone advise, please?

[1985 CCX]

Call KMS, my car has a Jaguar Diff and does not move....
I am buying a Diff from KMS now for second car, hope to avoid issues

[CompClassics]

That “star” adjuster is for setting up the differential gears.

[David Kirkham]

Originally Posted by rsk289

Can anyone give me some advice on Kirkham diffs in a 289, please?

My Kirkham diff has been in the car for about 4,000 miles now and has performed faultlessly. However I was on a run this weekend, but after pulling off the highway a loud screeching metallic noise became evident from somewhere in the rear of the car. I've checked everything over and can find no concerns with wheel bearing, brakes (no stones stuck etc.), inteference from cables etc.

In checking the driveshafts, I discovered that there is very noticeable up and down movement of the diff output shafts. I can move the right side one up and down about ⅛", and the left side one a bit less. I don't know if this right or not, but I've checked a spare Jag diff I have and that has no movement at all. There is a sort of star wheel adjuster in the casing which looks as if it can adjust the bearing and is held in position by a small locking plate.

Can anyone advise, please?

A little movement in the side axles is normal in our differentials. It shouldn't affect anything. We use a roller bearing. The Jaguar, however, uses a double taper roller bearing because the 1/2 shaft acts as the upper control arm and there can't be any movement in their bearings or the wheel will move around.

That said, if you heard a grinding or a metallic sound that isn't good--I didn't know you heard a metallic screech and that the differential apparently isn't working.

I wonder if something failed internally??? Bearing? Ring gear bolt? I don't know. We have had very, very few problems with our differentials so I really can't say right now.

Even so, pack it up and we will fix it! Please make sure you send it to our new address and we will turn it right around for you. If it is our fault (very well may be) we will fix it for no charge.

On 2nd thought...we will fix it for no charge regardless. It sounds like something we sold isn't working for you and that isn't cool.

David


Kirkham Motorsports
304 E 900 S
Provo, Utah 84606

[LMH]

That’s customer service right there!
Larry

[cobrakiwi]

Originally Posted by LMH

That’s customer service right there!
Larry

Could not agree more, outstanding customer service.

[rodneym]

Second to none.

[1985 CCX]

Feeling good about my differential purchase from KMS!
Hope David can help with other items...

[xb-60]

David, why aren't there more people in business like you? It's a no-brainer that good customer service pays great dividends!

Cheers,
Glen

[CompClassics]

I wish my client had had that option with their KMS differential, he only had 1500 miles.
Kudos David!

[David Kirkham]

Originally Posted by CompClassics

I wish my client had had that option with their KMS differential, he only had 1500 miles.
Kudos David!

Haven't you been able to get that differential sorted yet?

David

[CompClassics]

David Kirkham,

Yes, we had the differential rebuilt at my clients and my own expense.

[David Kirkham]

John,

Sorry about that headache.

On the bright side, the above customer found the problem. His rear hub bolt had come loose and the metallic screeching was from the hub and rotor coming loose. I imagine the rotor probably tilted over into the caliper. I have seen that several times.

I don't know who made his car or who built his suspension.

Check your bolts!!!

Important bolts to check!!!

rear hub (see above)
drive shaft
half shafts (I have seen several of these come apart)
ring hear (this used to be a huge problem until we developed our latest 17-4 PH stainless bolts. They are beasts).
motor mounts (both to the motor and to the frame)
caliper bolts (and the rest of the brake system)
throttle linkage (these slip more often than people think if they aren't tight)
differential mounts (both to the differential and to the frame)
all suspension bolts
steering system bolts--even the steering wheel!
KNOCK OFFS! (wing nuts, wheel nuts, whatever you call them).

I've probably forgot a few--please add any that I may have overlooked!

These cars are sometimes driven a bit hard and can use some love to check things out on a regular basis.

David

[CompClassics]

How about using the correct nuts and bolts in the builds to begin with? You can not go down to the local Home Depot to gong the correct hardware!!!

[rsk289]

Apologies for the late reply - David has been way above and beyond just 'helpful' in his response to my problem and very generous offer regarding fixing the diff.

First off - following David's advice, which he sent personally to me, hence my missing it on this forum - I started by draining the diff oil. This was to level, and perfectly clean without even that light grey dust you find on the tip of the drain plug. It looked like fresh honey. Thinking about it, I reasoned that it was unlikely that a failed component would make a hard, rotational metallic noise inside a diff that's full of nice, clean oil. Grinding or grumbling, yes, but this was almost like that noise you get when there's a stone behind a dustshield. So I pulled the NS hub to check the rear wheel bearing.

The retaining bolt into the stub axle had backed off half a turn, taking the tabwasher with it. This was just enough to take the pressure off the bearing inner race and spacer pack, and one of the bearing inner races had just started to turn on the stub axle. Hence the noise. I'd only driven it about 50 yards like this, so after careful dismantling and measurement of the interference fit (still 1.5thou) I cleaned everything up and reassembled with new seals, this time using a spot or two of Loctite bearing adhesive on the shaft for good measure. I found that polishing the topside of the new tabwasher, and the 'land' on the underside of the stub axle bolt stopped the tabwasher from picking up and twisting during assembly, and got the bolt to around 120lb/ft before knocking the tabs over which I think should be OK - it's not a race car and gets driven carefully.

There is a bit of lateral movement on the output shafts as David describes. At the roadside, I was making decisions with the car on the Cobra's Shelley jack with my hand pushed in from the side. I could only reach so far along the driveshaft, which may have increased the movement I could feel - I don't know. With the car on the lift back home, I could move the output flanges themselves and from what David has said I think these are within tolerance. With everything reassembled, a test drive has not thrown up any further noises or problems.

I don't, therefore, see this as in any way down to KMS. I apologise to David if this has cast any doubt on the quality of his product - but on the other side, to my mind this episode has demonstrated the absolutely excellent quality of his after-sales service. Thank you, David, it is really appreciated.

Roger