Differential Whine

Dear List,

I need your help and experience. Today I reassembled our TR6 after replacing the rear seal, clutch, pressure plate, all u-joints and updating the seals on the differential. However, I now have a rear end whining sound that I've never had before. The sound is only when decelerating and whether the tranny is engaged or not. Going downhill with my foot off the gas, it sounds terrible. As for the rear end work, I had my mechanic replace the pinion seal and the inner shaft bearing oil seal on the passenger's side. On the drivers side, I think he replaced the whole flange assembly part due to a "Seal Saver" issue that he had with the original part. What I need to know is what might we have done to change the rear end from a well behaved, quite participant to a noisy part of the ride. Your experience is needed, and thank you all.

They can become noisy when the backlash exceeds factory specifications. (especially noticeable when coasting/compression braking)

Also, they tend to lurch a bit during neutral/trailing throttle.

In this case it wouldn't be a bad idea to remove the rear end and have it re-clearanced.

What fluid are you running in the rear end?
Did the service man switch to some lighter/non-hypoid oil?

I developed a whine in the diff of my TR3A and about 400 miles later, I checked the oil level and found it was low. It only whined like the comments above. So I added oil and it continued to whine. It was about 1000 miles later that I had to had to have a new crown and pinion set installed. I removed the rear axle and took it to an expert who put in the new parts, new bearings and seals and set the clearance as per the manual. It's been fine (and quiet) since then, I've driven 51,000 miles since then and it's still quiet.

I wouldn't drive it too much before having an expert set up the shims for the right clearances. This should eliminate the whine.

Don Elliott, Original Owner, 1958 TR3A

https://www.britishcarforum.com/ubbthreads/photopost/showphoto.php/photo/1919/ppuser/4127

Sounds like the mechanic that did the differntial work didn't torque the nut on the front pinion correctly. Wouldn't that change the pinion setting? I know nothing about TR6 diffs, but some Spitfires have a crush spacer on the pinion, that once its set, it can't be reused.

I agree with Bill. If he changed the pinion seal, he had to take off the front flange. I think that on a tr6, there is a crush washer used instead of shims on the pinion tail. The crush washer sets the tolerance when the pinion nut is torqued to the specified setting and must be replaced rather than reused. If you had shims, he would still have to replace the used shim pack and torque properly but you wouldn't need to purchase a new crush washer.

Stop driving until you get it fixed. to prevent further damage.

Unfortunately, It would be better to pull the rear end. That way you can have it properly preloaded & backlashed.

https://www.quantumechanics.com

A quick fix might be as simple as getting a new crush sleeve and re-torquing.