Symptons of a diff in need of a refurb?

[Mr Plow]

Hi All

For some time I've had a clunking noise when lifting off or applying the throttle with a heavy foot I have been putting this down to drive train slack, however...

Since a weekend at Le Man classic the clunking has got worse, I also now have slight rumbling noise and sometimes a slight knocking noise when going round a corner, left hand bend or than right hand bends.

last year I replaced the UV joints and the year before the UJ's.

Could this be the diff in need of a refurb? What are the symptons of a tired diff?

Car is a later chim so has a BTR diff

Cheers

Liam

[QBee]

Up on a ramp at a TVR specialist first I would say

[Thundersports]

Agree. Trust me you don't want to take the diff out unless you really need to!

[QBee]

It could just as easily be a loose suspension bolt or something in the brakes. I had a clunking when I slowed or accelerated suddenly, and found I had one calliper bolt completely missing and the other half out. Another time I had a calliper bracket bolt sheared off. Any loose suspension bolt could make a noise when torque is applied or removed, and any of those faults could be dangerous. Many years ago i had a noise from the drive shafts on a Mini similar to that you describe - the U-bolts on the CV joints had worked loose six months after the joints had been replaced.

This is in my opinion a job for someone who has heard all the noises before and knows where to look - probably only take him a few minutes to find it and probably fix it. My TVR guy certainly would. And if it is the diff, he will know where to get it refurbed.

[Bassfiend229hp]

Thundersports said:

Agree. Trust me you don't want to take the diff out unless you really need to!

Is the diff really that hard to do? Doesn't look that much of a PITA from what I've seen but of course I've never tried it.

Mine's got a lot of play in it - enough that the continual thumping as I come on and off the throttle seems to keep working the nearside driveshaft bolts loose after about six months - so I should have a second hand diff coming at some point to replace mine with.

Phil

[Oldred_V8S]

Mr Plow said:

last year I replaced the UV joints and the year before the UJ's.

Liam

Liam

Sad to say this means nothing; there appears to be a lot of crap out there at the moment. Though it may be a cheaper fix for you, if they turn out to be the cause.

I changed a steering UJ before the 2013 Eurotour, only to find that 3000 miles later it was worse than the one I took off. The ignition coil I fitted for this years tour, lasted 300 miles! I have heard plenty of other similar tales.

[nigelj77]

Could the clonk you mention be a diff bush or one of the mounting bolts coming lose, I recall the rear bush being blamed for clonking?

As for refurb I've just had mine done by Grantua engineering, I spoke to John Read down there, seems very knowledgable and turned the diff around pretty quickly.

[mattrosersv]

First things first, check the front mounting plate bolts for the diff & bushes and bolts - driveshaft etc.

If you have had the CVs done recently it is possible that the bolts have worked loose. I have also suffered from this in the past, probably caused by some of the threads being full of grease and therefore the threadlock being ineffective.

There was a thread some months ago where a few of us had suffered from slack diff mount bolts allowing the diff to move. Mind you, I think in all cases the diffs had been out fairy recently.

Matt

[Mr Plow]

Hi All

Thanks for the replies.

Only got back from Le Man Classic last night so haven't managed to check all the obvious stuff. Hoping to have time tonight to have a proper look and check everything is tight and no play in CV joints or UJ's.

If its all tight and OK, then a trip to local TVR specialist for them to diagnose later in the week if I have time.

Are the diffs pretty reliable in these or do they need refurbing quite often?

Cheers

Liam

[Mr Plow]

OK so I've been under the car looking around. All bolts are tight, there is some play in the OS outer CV joint so that will need replacing along with the OS inner so the pair are done.

Can anyone suggest the best place to get a couple of CV joints?

I also have some play where the propshaft goes into the gearbox when the car is in gear, I presume this is normal as its just the gears?

Cheers

Liam

[wuckfitracing]

Bassfiend229hp said:

Is the diff really that hard to do? Doesn't look that much of a PITA from what I've seen but of course I've never tried it.

Mine's got a lot of play in it - enough that the continual thumping as I come on and off the throttle seems to keep working the nearside driveshaft bolts loose after about six months - so I should have a second hand diff coming at some point to replace mine with.

Phil

No its not hard to do, just heavy and awkward to remove. Just protect the chassis as you have to angle on its side to get it out and it scratches everything. I cut the arms from an old leather jacket and wrapped them around the chassis. Same for when you lift it back in its a lot harder but because of the space its a one man lift.

[Mr Plow]

Oldred_V8S said:

Mr Plow said:

last year I replaced the UV joints and the year before the UJ's.

Liam

Liam

Sad to say this means nothing; there appears to be a lot of crap out there at the moment. Though it may be a cheaper fix for you, if they turn out to be the cause.

I changed a steering UJ before the 2013 Eurotour, only to find that 3000 miles later it was worse than the one I took off. The ignition coil I fitted for this years tour, lasted 300 miles! I have heard plenty of other similar tales.

Hi Mate

You were right, looks like CV joints, hopefully anyway. Cheaper fix as you said.

Ordered a pair from Graham Goode Racing.

Cheers

Liam

[Oldred_V8S]

Mr Plow said:

Oldred_V8S said:

Mr Plow said:

last year I replaced the UV joints and the year before the UJ's.

Liam

Liam

Sad to say this means nothing; there appears to be a lot of crap out there at the moment. Though it may be a cheaper fix for you, if they turn out to be the cause.

I changed a steering UJ before the 2013 Eurotour, only to find that 3000 miles later it was worse than the one I took off. The ignition coil I fitted for this years tour, lasted 300 miles! I have heard plenty of other similar tales.

Hi Mate

You were right, looks like CV joints, hopefully anyway. Cheaper fix as you said.

Ordered a pair from Graham Goode Racing.

Cheers

Liam

Excellent news Liam. Fingers crossed mate.

[jamienshelly]

I had a knocking/clicking from my O/S cv's, i removed the driveshafts, stripped, cleaned and rebuilt them with new grease and they have been fine for a year now and still silent with no play. May be I was lucky but it has got to be worth a shot.
And the diff is a lot heavier than you think, its not impossible to lift, it just weighs more than you may think so be aware.

[TJC46]

Mr Plow said:

OK so I've been under the car looking around. All bolts are tight, there is some play in the OS outer CV joint so that will need replacing along with the OS inner so the pair are done.

Can anyone suggest the best place to get a couple of CV joints?

I also have some play where the propshaft goes into the gearbox when the car is in gear, I presume this is normal as its just the gears?

Cheers

Liam

Would seriously consider doing all 4. If the offside is knackered you can bet your bottom dollar the nearside wont be much better.