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Last year before I took my car off the road it had developed an intermitent rumbling/knocking from the rear end. I've since replaced both rear halfshaft bearings and fitted a new propshaft. I now have the car up on stands and when I run it in gear, every minute or so the rear diff will shake about and make clonking/rumbling noises, then it will stop for a while and run quite smoothly. This is what it was doing before I replaced the bearings & propshaft so that's made no difference. I can feel the same rumbling by holding the gearbox housing but only very slight so this may just be the vibration transfering down the transmission. Also the nearside wheel seem quite stiff & jerky to turn while the offside is quite smooth. The diff did used to whine and got worse when I renewed the oil. It stopped for a while when I put some molyslip in it but has since started to whine a bit again.
I'm thinking the diff is knackered but can't understand why it rumbles about for a while then stops and then starts again. It seems worse if i run it in 5th gear. I can feel the diff housing shaking/ knocking. Something also clonks when releasing the clutch to engage drive unless I do it really slowly.
Rebuilding the diff is beyond my capabilities and a recon axle is very expensive so don't want replace it until I'm fairly sure it's the cause of the problem.
Any ideas please.

Andy
1981 UK SPEC TR8
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Andy to me that sounds like a diff center bearing on it's way out. It could be the pinion bearing, or one of the planetary gears, but less likely. They usually fail fairly quickly once a problem becomes noticeable.

These diffs are well enough made to be able to swap your center & bearings for a replacement, without having to set up the new one. All you have to do is fit your crown wheel to the replacement center.

You should have no trouble picking up an SD1 centre, something that is getting very hard to do in Oz these days.

It is a simple job. My son got down to about 2 hours, in those days when he was regularly destroying centers. That was before I fitted the Skyline diff, which has resisted his efforts so far.

I expect Jclay's site would have instructions.

Hasbeen

Andy, my friend, please do NOT operate the car until the differential has been opened up for examination. I suspect a broken side gear has shed a chunk of metal and is rattling around in there as well as producing a rumbling/vibration. To operate it further risks a blowup. A BIG BLOWUP. I discovered this on my spare differential and promptly junked the whole thing. Your description of vibration inside the differential is a strong indication of dire goings-on.

If you have a complete spare rear end, I would install it now.

Mildred Hargis

You don't want to be driving it, it's not going to get any any better. If reading the adjustment part of the diff in the OEM manual doesn't scare you off, nothing will (and you should be working for NASA). While parts of it may be not too bad (see Hasbeen post), you've got nothing to lose. Easiest would be to buy a rusted out car that the owner can't sell and get the diff from it.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

I have read through the factory manual and it does seem like rocket science to me! I OK up to the point of removing the crown wheel and carrier but then I'm well out of my depth. I may take it out so I can look for any damage but it's looking like a replacement job. S&S can build me one for exchange, that's looking like my best bet so far. Probably a 12 hour round trip to get though.

Andy
1981 UK SPEC TR8
[img][IMG]http://i473.photobucket.com/albums/rr92/REPLIC8-2008/175-1.jpg[/img][/img] [img][IMG]http://i473.photobucket.com/albums/rr92/REPLIC8-2008/pics005.jpg[/img][/img]

You should take the cover off and remove the carrier. I had one where both cluster gear bearings broke and the cluster gears were flopping around on the spider gears. You have to remove the ring gear to check them and replace if that's the problem. Do not mix any of the spacers and you should be fine. Easy to check for play in the pinion shaft also. No special tools needed.

TR8

Hi Andy,

Have you had that rear cover off yet ? Is the drive flange nut tight ? or play in this area ?

May be worth looking out for an 3.5 SD1 axle on 'The Bay' rob the CWP and get a local axle specialist to fit it to yours.

Have a word with Simon or Rob on Sunday, Robsport, they may have something tucked away.

Cheers John


LIVE LIFE A QUARTER OF A MILE AT A TIME!

1976 Speke FHC Beauty

1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6,ON THE ROAD NOW KICKING AR5E !!!!

Took the rear cover of today, Everything inside from what I can see looks fine, no lumps of metal missing. I ran it on tickover with the cover off and the noise is horrendous. I think it's one of the pinion shaft bearings. the only other thing I can do is try to remove the front cover to have a look in there. It's deffinately the diff making the noise so it's looking like an expensive job. At the moment I neither have the money or am in good enough health to tackle this so it's going to be mothballed until things improve and I can sort it properly. You wont be seeing this TR8 out and about this year. [:(]

I will try to get to a few shows to see my friends and support the club as much as I can. Having said that I won't be at Stoneleigh tommorow so hope you all have a good time if you're going. [:)]

Andy
1981 UK SPEC TR8
[img][IMG]http://i473.photobucket.com/albums/rr92/REPLIC8-2008/175-1.jpg[/img][/img] [img][IMG]http://i473.photobucket.com/albums/rr92/REPLIC8-2008/pics005.jpg[/img][/img]