Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Clunk from the back of my 2008 plus four

There seems to be some slack in the transmission;a clunk which sounds when the drive is taken up.Assuming its not a UJ, is it normal on such a new car?(8000 miles), and if not, whats happening to the diff,and will it matter if I run it till it worsens?

Check that you wheel nuts are tight. If not the wheel can move on the splines.

Check the rear spring U Bolts. They are known to come loose. I have seen a +8 snap the U bolts on the hill climb at Brooklands.

David

Hi,
I have a 2011 plus 4 with exactly the same problem, when taking up the drive or coming to a stop a distinct clunk from thr rear.
I made the same post about a month ago, the best advice was 'did I have a limited slip diff?' the answer was no I haven't. I've checked every thing I can see including taking up the floor above the diff. housing, checking the shocks, battery cradle and wheel tightness. The noise doesn't appear to get any worse or any better for that matter, my first year service at Newtown Motors is due in August so I'm hoping someone can come up with answer at that time. Any further help or advice would be most welcome.
Cheers, Rog.

Hi Rog- intresting that your car is even newer than mine and has the same problem;I was gonna wait till the service in august and ask,too...the noise seems too 'clean' to be a UJ,and Im assuming its play inn the diff...................

It would be unusual to have wear in a low mileage diff, but there may be some play at the top end of what's acceptable. If you jack the rear up you can test the free play between each wheel. Generally speaking, diffs have four thrust washers. There will be one between each planet gear and the carrier (either end of the pinion pin). The other two are between the halfshaft gears and carrier. When you take up the drive, the pinion loads the crownwheel, and those four small gears load up. This can produce a loud 'click'. MGB's are notorious for this, and the thrust washers can be changed on a Salisbury axle in a couple of hours with no special tools.

Hi All,
I had exactly the same problem with my Plus 8 since she was new in 2003. The dealer (a good one) told me that it was a "normal Morgan noise". I checked everything but I didn't find anything wrong. I even made a claim to MMC, but I didn't get any good answer ("they all do that Sir..", very well-known answer). So after a lot of searches an American Morgan dealer told me that it was a known trouble probably because there was a little too much play between the splines of the hub and the ones of the wheel, but it is possible to go to 200lb/ft. of torque to tighten the wheels (16" stainless steel spokes wheels). So I packed carefully with copper paste and tighten to more than 200lb/ft. and it worked. The noise regularly comes back every year, when it is time to remove the wheels to repack the splines with fresh cooper grease. It works now for 9 years so I think my dealer was right, and after a lot of Morgan meetings, I realized that I often hear the same noise at rear end of many Morgan.
I hope it can help.
BR.
Daniel.

If its only 1x clunck when moving forward or reverse, this should only be BACKLASH, as DaveW suggests its distance allowance between all the little gears inside the rear diff (Planet Gears)each gear wheel requires a minute space, so you do not get lock up or seizure, the distance between each gear mulitplies (your Clunk)
Although possible to improve not always fully curable, IMHO best left alone and lived with, you will probably find it will go on forever.
This is a common noise exagerated by the fact you sit close to the rear of the car and it has very little sound proofing.

As Vampirex, I had a terrible clunk on my new +8. Such that if it could not be fixed I would have sold it. it went back to the MMC where I had the "they all do that sir". After a bit of back and forward arguments, the MMC seemed to through go through an attitude change, checked the wheels and found one outside manufacturers tolerances and 2 on the limit, they swapped all 5 of the "indian" wires for the then brand new stainless wheels and the problem was fixed never to return. Extraordianry service from the MMC.