I just finished up with a new transmission mount and now I have a horrid sound in the rear! Noise is there whether left or right wheel is spun. So either the drive shaft or differential has a problem. There was no issue before the mount replacement so I’m at a loss. U joint seems sturdy. If I put my hand on the rear seat it vibrates with the noise. I had to drop the exhaust but like I said it makes the noise if right or left wheel is spun. Posted on fb owners group and my next step is disconnecting the driveshaft and isolating that the noise is coming from the diff. If it is the diff why would replacing the trans mount bushing mess up a bearing or gear?

https://streamable.com/6fb4eo

https://streamable.com/twigrx

 

l can't help with specifics but almost certainly something to do with the mount work. Possibly centre cotton reel/support spring issue.
many years ago l had similar in my series 1 xj12 with jag 4 speed o'drive. I chased tail shaft changes, centre bearing changes and diff output bearing changes for what ended up being rear mount issue.
just happened to put some weight downward on the gear shift lever one day and the noises changed.
That's some 40 years ago but still remember in some detail.

 

well I mean if I did the mount bushing right. It should be at the proper stock height etc... so what would decide to make all hell break Loose in the rear diff?

 

Just a idea, Does your vehicle have the vacuum tube running through the transmission tunnel that is now rubbing due to the increased height of tranmission mount?

Larry Louton

 

I'm not sure if that... the sound is very rhythmic. If I spin the wheels it’s quite quiet but while driving (well obviously front he vids) quite loud

 

No reason that I can think of.

But sometimes a worn U-joint can make a clack/click sound. Maybe the driveshaft position changed a bit and the UJ is now operating at a slightly different angle and is in a sour spot, so to speak.

I'm not really sure, though, that the noise in the driving video is the same as the noise in the second video

Anyhow...

If you're 100% there's no other interference between something rotating and something stationary (drive shaft and exhaust heat shields, for example) then disconnect the drive shaft and see what happens. With the shaft disconnection manipulate the UJ in all directions. it should feel smooth as silk. if not, you may have found your problem

Cheers
DD

 

The gearbox mounting when installed gives very little clearance between the propshaft at the gearbox end and the rearmost support plate. I am pretty sure you have the prop fouling this plate. Nothing for it but to loosen the gearbox mount support plates and centralise the entire thing carefully.
If that does not do it, then the rearmost support plate has to come off too. Did you manage to screw in the two bolts on this rearmost plate that attach up in the tunnel? If not, that will be the cause. I am talking about this bit, and the bolts that go through the holes at the top of the half moon piece into the tunnel sides:
https://parts.jaguarlandroverclassic.../brand/jaguar/

 

This might help a bit.

 

I only touched the triangular mount... is there enough play in it once loose to “center” it? The drive shaft is definitely farther right near the differential, but I see no rubbing.

 

yeah this week I’m going to get under it and make sure nothing is rubbing. A year ago the right over the axel exhaust pipe had dropped and was rubbing the half shaft. Sounded a lot like this but this is way worse.

 

I guess I’m not aware of that support plate...is that mounted right above the mount system? The only thing though is the noise is coming from the rear... if I take the rear seat out it is even louder and I can feel it vibrate right in the center between the rear seats. I’m thinking it must be the driveshaft ujoint or pinion bearing exploded 🤷🏻‍♂️

 

larry you genius! I disconnected the driveshaft at the rear and got no noise in the diff so I was glad... but the u-joint felt super smooth and solid. I thought maybe the ujoint near the trans was bad. I saw the heat shield and thought well might as well take it off and look... feeling all around the tunnel and finally... a stupid metal vacuum? Line had broken it’s clip and was laying on top of the driveshaft near the ujoint!! Which in turn was making it hit in the rear where it goes in the trunk area. So Larry is the winner!

 

I would rather say that I contributed with happiness, but not to be a winner.

Thank you.

Larry Louton

 

that ahah moment when you feel metal line touching the driveshaft... that happiness cannot be bought! Ha