1850 Auto - Whine/Whirring Noise

[Matt1850]

1973 Dolomite 1850 Automatic, 34000 miles

Hi all,

I've recently noticed a whining/whirring noise coming from my Dolly. Does anyone have any tips for pin pointing it or likely causes?

The noise only occurs after a decent run at higher speeds (e.g. 30 miles at 50mph+), so when the running gear is warm. It varies with road speed and can still be heard if the gearbox is put into Neutral whilst the car is rolling. The noise disappears when the car is stationary. My wife and I both felt it was coming from the middle of the car but can't be 100% certain.

My main suspects are prop shaft carrier bearing or the differential. I plan to take the car for a run until the noise manifests, jack it up safely, put it in drive and crawl around underneath looking for the source of the noise. Any better ideas?

Thanks

[MIG Wielder]

Good diagnostics ! I'd do the simple things first. Can you check the propshaft U.J s please. If you have the U.J variant with the grease nipples in, give them some grease. If you have the variant with the blanking plugs, try fitting grease nipples. They do need to be the long variety though as on my 1850. I've left my grease nipples in as they do not seem to affect the balance.
Then check the oil level in the diff; better still drain it out and replace it ( syphon it; it takes a long time ) .
Then yes, replace the centre bearing. They are quite expensive though. Normally the rubber support disintegrates before the bearing wears .
You may find that the prop; has been replaced with a Sprint C.V. style joint in the past.
Not sure how that is replaced.
HTH,
Tony.

[Matt1850]

Thanks for this Tony, really helpful.

I'll check/grease the UJs first then and report back.

I checked the diff oil about 500 miles ago and it was overfilled by about 100ml (by whomever had serviced it last). I have no record for when it was last changed so will drain and refill. I have some EP90 Hypoid gear oil (API-GL4) in the garage, I believe this is the correct stuff to use?

Thanks again

[MIG Wielder]

Yes, the official workshop manual specifies " Gear oil SAE 90 EP " but doesn't give a GL rating for the U.K
Funnily enough the official workshop manual actually says API GL5 or MIL-L-2105B Hypoid 90 for top up only for Overseas territories.

One thing I learned from the same book is that early models were fitted with a 2-piece prop; with flanges behind the centre bearing. I've learned something today ! This doesn't appear in the early 1850 parts book.

[Carledo]

While you are underneath checking, pay attention to the rear wheel bearings too.

I had one fail on my one-and-only 1850 with little more warning than a light, road speed related whirring from somewhere behind me, till the whole half shaft fell out of the axle and left me uncomfortably close to a junction with no drive, no brakes, unable to push and had to be recovered by rear end suspended tow!

Not an experience I want to repeat!

Not that it's a common fault, it isn't! I've had LOADS of Dollies since and done probably 100,000 miles in them cumulatively without a repeat!

Steve

PS manual gearboxes and particularly overdrive gearboxes need GL4 rated oil because they contain brass components like baulk rings etc which don't like GL5. The axle doesn't have any brass in it so GL5 is okay there. In fact I run my slightly whiney Sprint diff in the 1500 on EP75/140 GL5, shuts it up a bit! But, generally speaking I run EP90 GL4 in everything, it saves having to check which bottle you are using every time!

[Matt1850]

Thanks for the help, sorry I haven't been able to provide a response yet. I've been busy with my wife's car (Rover Streetwise), we recently bought it and it's needed quite a lot of work for the MoT test including making up a couple of sill repair panels, cutting out the rot and welding them in.