Why is my rear end knocking under load?!

[CV35Ian]

Hi
Manual O/D 73 Stag,
When letting off the accelerator, there is a definite knock at the rear end,it also happens when I reapply power, and occasionally when cornering and the rear wheel hits a pothole/gravel.
It looks like there is some slack in the diff (ie the prop turns a bit begore engaging and moving the car).
Another symptom is if i hold the car on the clutch, and then move off (very) occasionally the rear wheels lock after a metre or so and the car stps very quickly! Rectified by selecting reverse, going back 1/2 metre and then moving off.
Any ideas what this could be and how to sort it - car is still driveable (did 100 miles today) but the knocking is a bit unnerving.

On the plus side the new 4 core rad and flush through has been a success, and the original Blaupunkt Radio Cassette has been reconditioned, an aux socket added and is on its way back to me.

Any help on the diff/drive issue would be appreciated - diff oil level has been checked and is fine.

Thanks

Ian

[tjk]

Ian
I would not drive again till you know whats going on ,sounds to me if some thing is above to break. Im sure someone will give you a few ideas in the right direction.

Tim

[flying farmer]

Sounds very much like you have a broken tooth on the diff. I once had one of the small gears in the diff shatter (Dolly Sprint axle, but very similar diff powered by a 3.9 Rover V8 in a Toledo, long story) with the result that the diff locked solid resulting in a very hairy moment until the crownwheel shoved the bits out through the axle casing and freed off the rear wheels.

I would seriously suggest dropping the diff and removing the rear cover for a peer inside before something really unpleasant happens!

Neil

[Staggard]

Propshaft/driveshaft UJ's I think you should also check the quill shaft housing for cracking if it has not been reinforced. Graham

[Stagdad]

Mine locked up in reverse and i found these bits in the bottom of the diff case (not the coin).Lucky it was 5mph on my drive and not 70mph on the motorway.Went for bmw diff after that.Stag diff bits 002.jpg

[GDPR]

I'm with diff too - you may get away with changing just the planet gears if you sort it now, but definitely don't drive it!

[LAMBRETTLAD]

I had a total diff lock in a transit van last year at around 65 mph,very scarey and lots of smoke ,and confused cars following behind ,no warning ,no brake lights ,very lucky there was no serious accident .

[Arbman Al]

Mine locked up in reverse and i found these bits in the bottom of the diff case (not the coin).Lucky it was 5mph on my drive and not 70mph on the motorway.Went for bmw diff after that.[ATTACH=CONFIG]33858[/ATTACH]

Can you do 70mph in reverse then??

[Stagdad]

Can you do 70mph in reverse then??

I knew someone would jump in on that one

[CV35Ian]

Weird I posted a reply that's not here.

Anyway thanks, didn't reply earlier as ive stopped receiving email alerts to posts (?), Im going to look at a replacement diff or rebuild existing - Rimmers have two Diffs, one is £760 and the other £460 - anyone know why prices vary so much?

Or is there another source of recon/replacement diffs that is less pricey - shouldn't have ordered new hood/frame!

[mallardstag]

...Or is there another source of recon/replacement diffs that is less pricey - shouldn't have ordered new hood/frame!

http://www.ejward.co.uk/new-parts/engine-gear-box-and-servicing/propshaft-and-final-drive/differential-recon.-exch-3.45-1-ratio.html

http://www.ejward.co.uk/new-parts/engine-gear-box-and-servicing/propshaft-and-final-drive/differential-recon.-exch-3.7.html

[mallardstag]

anyone know why prices vary so much?

Higher priced items have new crown wheel and pinion fitted.

[Mike Stevens]

Play in the diff input shaft is quite normal and not really a problem (except for the 'clunk'), but the locking up doesn't sound good at all! The play is relatively easy to deal with by replacing the sun and planet wheel thrust washers.

However, it sounds like you need a new diff anyway, so thrust washer replacement should come as part of the package!

Cheers,
Mike.

[CV35Ian]

Thanks
So recon is just bearings and a check up, the more expensive on has the biggest internal part replaced (am looking at diagrams).

Hmm, funds may not permit the more costly one.

[Tdm]

To CV35Ian - I wanted to reply to your PM thanking you for the info you sent me regarding blaupunct radio/cassette repair,
but I get an error message saying you have opted not to receive PMs any more. So put my thanks on this thread.
Terry