Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rear Axle Lubrication

I am looking to change the axle oil in my 1992 Plus 8. I have recently bought the vehicle and there is no record of when this was last performed - hence time to change it.

As a novice in this field I want to pose a few questions before embarking on it.

1. The axle is fitted with a limited slip differential, hence I was going to go with Mobil One 75w-90 synthetic gear lubricant LS. Thoughts?
2. What volume of oil is required?
3. The drain plug appears to be oily. Is there a sealing washer on the nut or would you recommend the use of a thread sealant?
4. Can you confirm where the fill nut is? Is this it?
https://flic.kr/p/2pFRSEN
5. Where would I find the grease nipples? Is there a recommended way to grease these?
Additional photos:
https://flic.kr/p/2pFJXRL
https://flic.kr/p/2pFRJ56
https://flic.kr/p/2pFRJ68
https://flic.kr/p/2pFQurj

Thanks for your help.

David,

I'm in Central Illinois. 1986 Plus* Vitesse.
I use Red Line 75w-90 Gear oil. It already has the friction modifiers for a limited slip Diff. I buy from Pegasus Racing in Wisconsin. https://www.pegasusautoracing.com/

The drain plug is under the 'pumpkin'. The filler is on the rear of the Differential, a bit lower than half way down. PITA refilling, you'll need a funnel and hose. The fuel tank will be in your way.
The filler nut is a square headed pipe plug. Fill the case until it just starts to weep. I use a non-curing thread sealant on the plug. I use Hylomar Blue. Do NOT over tighten, it is a tapered pipe thread and you can booger things up...

If you have the LT-77 or R-380 tranny, the Red Line MTL works nicely.

Ron Davis

Plenty of info here

The link above does not address the older Morgans (pre 1962). Is it assumed that I should use the info for those on 1962?

Just the usual old thing of undoing the filler plug before you undo the drain plug ... so you know you can refil before all your diff oil is in a pan on the floor and your car's a paperweight 🙂

K

Here is the full page on axles.

I have no idea for a 62 car. Try the MSCC historic register people.

Thanks Ron, this is very helpful. Do you know how much oil the rear axle takes? I’ll pick some up this weekend.
Thanks again. David.

The earlier 3HA axle is more or the same as the 7HA in terms of bearings and seals. Dimensions are a bit shorter than the 7HA though

I've use 75/90 in my Salisbury axles with a bit of Molyslip.

PTFE tape on the drain and fill plugs.

Drain plug is a magnetic plug and is lock wired to one of the diff cover bolts.

Top tip is to keep the 3mm breather hole on the axle tube clear else the axle will pressurise and force the oil past the seals

Hope this helps

Arwyn

Arwyn, does the position of these breather holes vary? Top, bottom, inboard, outboard etc. I've searched for them for years on my two axles , both Salisbury, with out success. I'm beginning to think they have an element of unicorn nostrils about them. 🦄

This is where mine is - took some finding and needed a good clear.