P38A Worrying whine from front end -road speed related

Hi again,

the tales of woe just keep on flowing…
Have returned from the lakes and just deposited caravan around storage facility but the poor old girl has developed a slightly alarming ‘whine’ en route.

The noise is road-speed related rather than engine speed. Fluid levels that I can check seem ok.

currently at Stirling services in the rain and going to attempt to
Nurse her home the 50 or so miles.

anyone have any thoughts ?

my worry is that, having had the rear diff replaced before the trip, could this be the front one on the way out ?
The front prop shaft was replaced in the summer -but by an imbecile (not me).

any wise words or notes of caution ?

min an ideal world I wouldn’t drive her at all but it’s bleak in Stirling and the kids are in the back.

thanks again…

sorry to be a continual pest / source of amusement

Bob

Did you check the VCU? If it's seized you can get a kind of whine from the tyres and it knackers the diffs. I'm sure you will have checked the oil level in the diff.

No, foolishly I don’t check
The VCU before setting off -although I’m pretty sure I asked the garage (car was rescued when rear diff went) to check it (and I assume they would ?)

haven’t checked the diff oil level as it’s only just happened, had it changed a year ago.

is there an easy way to check it out ?

I worry whether it’s safe to nurse it home.

just another thing to add to the long, wallet-emptying list ! -although, when she’s done, she’ll be great !

Bolocks.

got about 5 miles before it went very wrong…

1/2” drive in the top of diff (not bottom one!). Breaker bar or drive. if it’s not stone cold should have a dribble of ep90 out of it when opened

Edit just saw ^^^

What’s gone bang bob?




Pics or it dint appen

The whine baca me a rumble and then a horrible running scuffing noise.

Not quite as dramatic as the rear, no vibration, etc.

Maybe it’s just a UJ this time ??!

it did let go a delightful odour of oil just after it let go.

can’t see anything obvious but I’ll need to
Get underneath her to be sure.

will be kicking myself if it’s the Viscous Coupling

Front diff gone, due no doubt to a seized viscous coupling. Does it still drive? If it does you should be able to limp home.
From what I have read, the most common cause of diff failure is transmission wind up caused by a seized VCU . If the front diff has gone, you have in effect a 2 wheel drive car.
It's usually the front diff that cries enough first.

RAC on way to recover her (and me hopefully)

will investigate in the dry and after pay day as rear diff nearly cleaned out my RR fund !

is the front diff more of a pain than the rear to swap out ?

and is the VC a specialist job ?

thanks again

Bob

Your not having a good time with this atm
VC is prop off and unbolt and remove

awkwardbob said:

RAC on way to recover her (and me hopefully)

will investigate in the dry and after pay day as rear diff nearly cleaned out my RR fund !

is the front diff more of a pain than the rear to swap out ?

and is the VC a specialist job ?

thanks again

Bob

Click to expand...

Front diff is much the same as the rear, just a bit harder to get the hub out as they rust in.
I doubt the garage new how to test the VCU.

Bugger… so…

wheels off, discs off, hubs and driveshafts out ?

then hope that the diff itself isn’t a rusted disaster area.

possibly a stupid question (the latest in A Series no Doubt) but is there a way to check for sure the diff is goosed ?

and, while I will look at RAVE, Is the VC likely something the (semi-competent) amateur can change ? -or am
I jus t giving myself more trouble ?

I’m always happy to learn about how the various bits work but I do need to know my limitations and not end up over my head !

-and thanks again.

awkwardbob said:

Bugger… so…

wheels off, discs off, hubs and driveshafts out ?

then hope that the diff itself isn’t a rusted disaster area.

possibly a stupid question (the latest in A Series no Doubt) but is there a way to check for sure the diff is goosed ?

and, while I will look at RAVE, Is the VC likely something the (semi-competent) amateur can change ? -or am
I jus t giving myself more trouble ?

I’m always happy to learn about how the various bits work but I do need to know my limitations and not end up over my head !

-and thanks again.

Click to expand...

Get a grip of the flange where the prop bolts and you will probably find it's wobbling about like a cock in a three cornered hat.As previously posted, unbolt the rear of the front prop where it bolts to the viscus coupling output flange.unbolt the mounting nuts/bolts drain oil and lift out.

awkwardbob said:

Bugger… so…

wheels off, discs off, hubs and driveshafts out ?

then hope that the diff itself isn’t a rusted disaster area.

possibly a stupid question (the latest in A Series no Doubt) but is there a way to check for sure the diff is goosed ?

and, while I will look at RAVE, Is the VC likely something the (semi-competent) amateur can change ? -or am
I jus t giving myself more trouble ?

I’m always happy to learn about how the various bits work but I do need to know my limitations and not end up over my head !

-and thanks again.

Click to expand...

Looking in Rave you should be OK changing VC

To check the VC without going in there, jack up the RHS front wheel, put the transfer box and transmission in neutral, fit your wheel brace or a breaker bar with 27mm socket. Lean on the bar and the wheel should rotate very slowly. It takes a fir amount of force. If it does move slowly, then the VC is working. If it doesn't, even if you stand on it, then it is seized.

You can do the job yourself. You have to remember that one of the transmission mounts is on the VC, so you have to chock up the transmission. Apart from that it is bolts out, VC out and replace. Easier if you have a hoist. If not then up on ramps either at the front or both on the VC side to give you access to work.

Marshall8hp said:

To check the VC without going in there, jack up the RHS front wheel, put the transfer box and transmission in neutral, fit your wheel brace or a breaker bar with 27mm socket. Lean on the bar and the wheel should rotate very slowly. It takes a fir amount of force. If it does move slowly, then the VC is working. If it doesn't, even if you stand on it, then it is seized.

You can do the job yourself. You have to remember that one of the transmission mounts is on the VC, so you have to chock up the transmission. Apart from that it is bolts out, VC out and replace. Easier if you have a hoist. If not then up on ramps either at the front or both on the VC side to give you access to work.

Click to expand...

There is no neutral in the P38 transfer box and I don't remember any gearbox mounting on the VCU flange.

Putting a fuse in slot 11 will neutralize the transfer box.

awkwardbob said:

Bugger… so…

wheels off, discs off, hubs and driveshafts out ?

then hope that the diff itself isn’t a rusted disaster area.

possibly a stupid question (the latest in A Series no Doubt) but is there a way to check for sure the diff is goosed ?

and, while I will look at RAVE, Is the VC likely something the (semi-competent) amateur can change ? -or am
I jus t giving myself more trouble ?

I’m always happy to learn about how the various bits work but I do need to know my limitations and not end up over my head !

-and thanks again.

Click to expand...

With the fron

Marshall8hp said:

Putting a fuse in slot 11 will neutralize the transfer box.

Click to expand...

That is true but not necessary.
Auto Box in neutral, hand brake on or off to test the VCU.

Datatek said:

With the fron

That is true but not necessary.
Auto Box in neutral, hand brake on or off to test the VCU.

Click to expand...

can I still test it if the diff is toast ? Or will that complicate matters…

awkwardbob said:

can I still test it if the diff is toast ? Or will that complicate matters…

Click to expand...

If the diff is toast, you can test the VCU with the prop shaft off where the prop shaft connects on the front of the transfer box, it's just a bit less convenient.

You can also drive in two wheel drive if you can get the front prop off ,there should be no strain on the front diff so should get you home . ....