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MG MGB GT V8 Factory Originals Technical - Axle howl - will it fail?

Folks,

My rear axle howls, more so on the overrun. It also suffered from 'clonk' when changing gear. I did the thrust washer thing - a very patience consuming job - over the week end. Vastly improved the 'clonk' situation, did nothing for the howl.

Can I just ignore it? I can put up with the noise - you can't hear it with the hood down, anyway. I just don't want to be stranded somewhere (or, infinately worse, my wife to get stranded). So, is it likely to fail completely?

Thanks,

Nick

PS It's a '77, don't know when it was converted.
Nick Wilson

Nick, if you can, check to be sure it is the axle howling and not the tranny. I fixed my "rear axle" howl by switching to 85-140 gear lube in the tranny.

good luck,
sean
Sean Squires

Sean,

How do I check that? If I put the car in neutral at speed, how much of the gearbox still rotates, driven by the axle? I'll try it and see what happens.

Thanks for the suggestion.

Nick
Nick Wilson

Nick,
I'm not sure how to check it. I fixed mine by accident. Did a drain and fill on the tranny and just switched over to the thicker stuff and solved my noise problem. I thought the whole time that it was in the axle until I got rid of the 20W50 in the tranny.

good luck,
Sean
Sean Squires

My axle whines gently too, and I was thinking hurrah, one expensive axle rebuild coming up. Then I noticed that the noise gets worse when the suspension loads up, which now makes me think it's a wheel bearing(s). I think the way to check whether your pinion backlash is excessive (which is what would be causing gear noise) is to put the car in neutral and the handbrake on then see how far you can rotate the propshaft. From what I recall from a magazine article about 5mm free movement at the propshaft/axle flange is what they did when new and anything over 9-10mm and you'll need an axle rebuild. Anybody like to correct me on the backlash limits? like I say, this is from memory. Another thought. Are all mgb back axles noisy? this is 1960s technology remember, they make have considered a certain level of noise as normal.

P.S. don't you love the smell of gear oil?

Phil


Philip Shingler

Hi

The information is in the Linsey Porter book but I can't remember the figures right now. Mine had excessive play, then I replaced the thrust washers which reduced it to something like 3-4 mm and eliminated the 'clunk'. Only a few days later the 'clunk' is back (presumably a bit of driving seated everything). I guess I cannot get oversize thrust washers - not that I fancy doing it all again!

Phil, it's not _too_ bad a job to pull the halfshaft out to check the bearing BUT if the bearing does need replacing you'll need the assistance of a press as they are tight as a duck's a*se on the shaft.

Nick
Nick Wilson

Many axle conversions, if it is a 3.07 to 1, howl due to some problems with the CW&P mesh. This will continue for many years and give no reliability problems, but long before that the owners ears give up and a solution is sought. More noise on the overrun, which can be very effectively pinpointed if the rear battery box cover is removed for a short drive, is commonly due to gear mis mesh in the axle.

Short of removing and rebuilding there is only an option of changing the lubricant or adding an additive, Land Rover have one for Range Rover and Disco where customer complaints of axcle noise are received. It often reduces noise to a point of acceptability in those and I have seen it reduce the noise on a V8 axle also. Clive Wheatley MGCC V8 spare supplier, can probably identify the product I refer too as I can't remember it's title.

Another point to bear in mind is that if the axle is a genuine V8 one then I have seen axles that have excess wear that has not been possible to rectify during rebuild. Because the genuine factory axle assembly is rare some rebuilders shy away from the problem of excess wear and try and 'shim it out' as they can't get original replacements now and a new CW&P conversion is really the only solution. This must have lead to a number of V8 axles being 'rebuilt' and put back into service with only a short potential service life.

Rog
Roger Parker

Nick, I have run a 3.07:1 diff in my roadster conversion for nearly 10 years and 100,000 miles, it has more or less whined from the start, I was somewhat peeved having paid around £500 for it at the time !
Regular changes of EP90 seem to have kept it going.
Good luck.
Guy.
Guy

Shortly after I bought my roadster over 10 years ago the back axle lost all its oil, and that started it whining. Carried on doing it for another 10 years and 25k miles, getting slightly less if anything (I did put some more oil in). I only changed the axle last year to fit a genuine w/w axle to finally stop the rear tyres fouling the arches following a conversion from Rostyles. Less torque on the 4-cyl axle I know, but still ...

PaulH.
Paul Hunt

This thread was discussed between 30/08/2000 and 03/09/2000

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