MGB There"s a clunk in my B.

[Walpole]

just prior to putting the car away for the winter I noticed on the last few trips a clunk when releasing the clutch. The gears changed smoothly so I don't think the clutch or the transmission ('78 with OD) is the issue. Wondering if the problem is the drive shaft or the differential. Any thoughts?

 

[Mickey Richaud]

Could be either one, but driveshaft (u-joints) would be the easier fix. Crawl under, grab it and give it a turn to see if you notice any slop. If so, replacing the u-joints isn't too difficult.

If it's the diff, it's most likely due to worn shims and that's going to require more work. However, the diff is pretty robust, so it can take some abuse.

By the way, the worn shims will typically give off a clicking sound; failing u-joints, again typically, make more of a clunk.

Let us know what you find, and good luck!

Cheers!
Mickey

 

[Walpole]

just prior to putting the car away for the winter I noticed on the last few trips a clunk when releasing the clutch. The gears changed smoothly so I don't think the clutch or the transmission ('78 with OD) is the issue. Wondering if the problem is the drive shaft or the differential. Any thoughts?

Thanks Mickey. I am hopeful of the issue being the U-joints as it looks like a lot of pulling apart to get at the shims in the differential. Cheers, Dave

 

[vping]

Could it be the rear U bolts? Do you notice a pull either way when you ease on and off the gas?

 

[crankjournal]

Differential pinion (spider gear) thrust washers. you do not need to remove the differential.
Len Fanelli
Abingdon Performance Ltd

 

[Walpole]

Could be either one, but driveshaft (u-joints) would be the easier fix. Crawl under, grab it and give it a turn to see if you notice any slop. If so, replacing the u-joints isn't too difficult.

If it's the diff, it's most likely due to worn shims and that's going to require more work. However, the diff is pretty robust, so it can take some abuse.

By the way, the worn shims will typically give off a clicking sound; failing u-joints, again typically, make more of a clunk.

Let us know what you find, and good luck!

Cheers!
Mickey

Checked the driveshaft and there is a good 1/4 inch of play in the connection to the diff. In the past I have been ordering parts from Moss which has been fine but I have found a distributer more locally in Oakville Ontario near where I live. They stock a wide inventory in Can $ and I have ordered a couple of u-bolts and a yoke and flange just to be sure when I pull off the driveshaft.
FYI the company is Peninsula Auto Parts > Peninsula british parts <.

Dave

 

[Walpole]

Differential pinion (spider gear) thrust washers. you do not need to remove the differential.
Len Fanelli
Abingdon Performance Ltd

Hi Len
Can you tell me more about the procedure to do this? Do you need to pull an axle to release the gears and then replace the thrust washers? There are several You Tube videos which describe the process. Looks like fun.
Dave

 

[JPSmit]

Checked the driveshaft and there is a good 1/4 inch of play in the connection to the diff. In the past I have been ordering parts from Moss which has been fine but I have found a distributer more locally in Oakville Ontario near where I live. They stock a wide inventory in Can $ and I have ordered a couple of u-bolts and a yoke and flange just to be sure when I pull off the driveshaft.
FYI the company is Peninsula Auto Parts > Peninsula british parts <.

Dave

Glad that is working out! can I also recommend British Auto Sport just outside of Dundas - HWY 5 west of Clappison's corners. Fred is a Moss distributor and generally I find more reasonable prices than Peninsula - > British Auto Sport <

 

[Walpole]

Thanks for the input friends. I replaced the u-joints at both ends and the yoke and flange on the transmission side. There is now no play or clunk and the shifts are smooth and immediate. Very happy to have avoided the replacement of the washers in the differential - at least for now.

 

[Mickey Richaud]

Thanks for the input friends. I replaced the u-joints at both ends and the yoke and flange on the transmission side. There is now no play or clunk and the shifts are smooth and immediate. Very happy to have avoided the replacement of the washers in the differential - at least for now.

YAY! Glad you dodged the bullet!

 

[Grantura_MKI]

Would have probably checked the diff since you had the prop shaft out already.

 

[YakkoWarner]

How DOES one check the diff washers? My car has the transmission and driveshaft out already for other reasons - if this is something that can be done by normal people with normal tools it would be worth doing. If it requires a degree in mechanical engineering and/or experience in surgical procedures then maybe it is best left to a professional?

 

[Grantura_MKI]

On later diffs, like this one is one can remove the rear cover to check end float, etc.
If it where a banjo, thats a different story.