Jump to content

Rear end whine


Mike R
 Share

Recommended Posts

Thanks for comments ...

 As I understand it bearing whine increases with load / throttle, wheras too low pinion pre-load can also cause whine... but are on deceleration / part throttle like mine. If you look at the early comments on this thread its fairly consistent about that. Also, bearings relatively new ... at least in terms of miles.

Must admit .... I thought looking at the workshop manual that the pinion is held in the front casing and the crownwheel in the rear via the half shaft bearings, therefore the amount of mesh could vary with tightness of the casing bolts? Sorry have I got this wrong?

ta,

Mike

 

36B663A5-6DEF-4D6E-AACF-1393E880A28F.jpeg

Link to comment
Share on other sites

not really the rear case only supports the output shaft hsg. the CW is held with bearing caps in the front case 

easy way to get some feel for pre load this needs the drive shafts disconnecting and is a measure of the whole assy not the figures for the pinion

measure dia of the diff pinion, wrap string around a few turns and pull witha small spring balance.

need to calc the   lb ins  from the load and coupling diameter ,   new without seal is 12 -16 lb ns  ( just the pinion) 

a used oil seal wont affect the readings ,  the crownwheel has a preload by nipping the bearing by 0.003" so not that much , no figures in my books 

but give the nut a 1/8 turn wont kill the bearings  as a nylock + collapsible spacer  , castle nut had solid spacer and shims .

easy to pop the tail bearing out and remove a shim , for a test like reduce by 0.003 to 0,005 " 

worth a play 

 

Link to comment
Share on other sites

Ahh I see now, didn’t realise there are 2 bearings each side, with the carrier held by inner bearing bolted to front casing. I do find that differential drawing difficult to follow.

Well many thanks ... I’ve learnt something today.

It did seem to significantly improve noise though, so maybe an acoustic affect as mentioned earlier ... but time will tell. Just wanted motorway driving to be a little less painful on the eardrums.

Pete ... thanks for the tips - I’ll keep a note of those for the next time I’m delving around in that area.

ta,

Mike

Link to comment
Share on other sites

I've just rebuilt my Mk3 Spitfire diff. You need a good selection of shims and some of them are no longer available. I ended up making my own from flat shim stock. All new bearings, correct preload (not easy to measure), mesh checked with Engineers Blue. A complete pig to fit hypoid unit back into housing without the special spreader. Even then it is far from silent.

Link to comment
Share on other sites

Ye dont need a spreader, just spread the bearings !!!

re 140 oil, use the Penrite 85/140, thin at cold, thicjens whenst hot,

best ive ever used. 20£ for 2 litres frae Dave Parker at Classic group

fully syhthetic too.

oil is cheeper than diff, change yearly, mine get change 2 some thins 3 a year.

 

re whine, its V V hard t,shift a whine ona  olde diff

teeth ev worn into each other, shift,n em even a few thou meks it whine.

 

bloke on TR forum had a perfect pattern, coast an drive, ubder loadings too,

he thought he,d cracked it, it still whined.

 

Rodger had same problemo, started efter it wer re done,

 

Me own spent hours onit, it whines at 55-70, then goes away,

every things tight, nee sideways movement on carrier.

 running up wid a drill dont let ye hear a whine, but it does owt else

 

ye can be talk,n of a 1-2 thou pin shime, or same ont carrier bit.

 

it really is trial an error I finn,n oot on worb olde units.

 

Main culprits is olde diff oil full of contaminants, an bits of metal wizz,n about int oil, as ye no got a plug init,

nor a magnet ont fill plug, which collects moer sheite than a sump plug does.

 

re fill,n,

get yer sels yan of thee,s, great wee thingys, shop aboot, they maybe like how  the Little Birdy sings,

https://www.ebay.co.uk/itm/New-Oil-Fluid-Suction-Vacuum-Transfer-Hand-Syringe-Gun-Pump-Extractor-Gear-Oil/232969691602?hash=item363e1361d2:g:SvsAAOSwE-5bxz7e

 

I did fin, an  also a fellow GT marra fun the same,

the red poly bushes at frunt did give a resonance at higher speeds.

M

 

 

 

Link to comment
Share on other sites

 

50 minutes ago, GT6M said:

Ye dont need a spreader, just spread the bearings !!!

 

Without a spreader I had real problems getting the shims in behind the bearings to give the specified 3 tho' preload, in fact I gave up and just got as much as I could and still get a good mesh marking.

Link to comment
Share on other sites

the hardest to do diy is measure the mounting distance

without some decent measuring equipment you need to accurately calculate the shims under the pinion thrust brg, to the projected cone dimension to the centre line of the crownwheel  brg, bores. And add the best run +- on the head .

its where a mandril and slip gauges come in useful  , we all have them !!!!   Easy to play for hours with trial and error more blue 

gleason paste is best ,,, heck knows if that still about, and you end up with a howler

 

Link to comment
Share on other sites

  • 3 weeks later...
On 04/04/2019 at 20:35, GT6M said:

Ye dont need a spreader, just spread the bearings !!!

re 140 oil, use the Penrite 85/140, thin at cold, thicjens whenst hot,

best ive ever used. 20£ for 2 litres frae Dave Parker at Classic group

fully syhthetic too.

oil is cheeper than diff, change yearly, mine get change 2 some thins 3 a year.

 

re whine, its V V hard t,shift a whine ona  olde diff

teeth ev worn into each other, shift,n em even a few thou meks it whine.

 

bloke on TR forum had a perfect pattern, coast an drive, ubder loadings too,

he thought he,d cracked it, it still whined.

 

Rodger had same problemo, started efter it wer re done,

 

Me own spent hours onit, it whines at 55-70, then goes away,

every things tight, nee sideways movement on carrier.

 running up wid a drill dont let ye hear a whine, but it does owt else

 

ye can be talk,n of a 1-2 thou pin shime, or same ont carrier bit.

 

it really is trial an error I finn,n oot on worb olde units.

 

Main culprits is olde diff oil full of contaminants, an bits of metal wizz,n about int oil, as ye no got a plug init,

nor a magnet ont fill plug, which collects moer sheite than a sump plug does.

 

re fill,n,

get yer sels yan of thee,s, great wee thingys, shop aboot, they maybe like how  the Little Birdy sings,

https://www.ebay.co.uk/itm/New-Oil-Fluid-Suction-Vacuum-Transfer-Hand-Syringe-Gun-Pump-Extractor-Gear-Oil/232969691602?hash=item363e1361d2:g:SvsAAOSwE-5bxz7e

 

I did fin, an  also a fellow GT marra fun the same,

the red poly bushes at frunt did give a resonance at higher speeds.

M

 

 

 

GT6M, picking up on your recommendation of Penrite 85/140, I've just been looking at it, it does look to be the bees knees but it's a GL5. Pardon my ignorance but does that matter, are there any brass components in a diff?

Link to comment
Share on other sites

General note, some gl5 oils are yellow metal safe. And some gl4 are/were not kind to yellow metals. It really is a minefield, but the best thing to do is contact the manufacturer. 

Marcus will hopefully get back soon to confirm things. But I suspect he has done his research...

Link to comment
Share on other sites

the diff gear  and planet th rusts are a yellow metal mixture  

if its of the disolve type 5  then diffs are the most susceptible high loads high temperatures   more so than gearboxes

Pete 

i found out on warranty as supply was brought in line with renault and 2 yrs of dodge diffs went slack . caused  a .nightmare 

 

Link to comment
Share on other sites

Thanks for the replies, guys, It really is a minefield, quite confusing... I'll have to do some homework, care needed here. I have tried a 140 oil and it was nice and quiet when cool but on the first decent run I went on and the diff got up to temperature, I wasn't too happy at all. ( I now have a drain plug a drain plug in the diff so changing the oil is fairly easy.)

Link to comment
Share on other sites

Dynolite oils are an interesting read.

The gearbox/transmission oils;
Two 85W-140 oils. Both GL5. One has sulphur. One EP & one not.
One will reduce noise but WILL wear on something that is worn.

Mine whines on acceleration and has not changed for 5 years. My symptom seems difference to everybody else. Filled with redline 75W90 & later MolySlip additive. Noise same.
I might just try an 85W140. It will not by a Dynolite oil.
Cheers,
Iain.
 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...