• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

transmission lubricant

Share this page

A

Arch 93

Senior Member
Offline
I've been advised by several sources who supposedly know from where they speak and I think I've also read it somewhere, that SAE 30 non-detergent oil should be used in the transmission/o.d. of a 100-4. The other day I was glancing thru the latest Moss Motors catalog (pg. A-27) and noticed they have 75W90 Gear Oil for sale as "Transmission Oil". This is what I use in the differential and steering gear box. I just drained the transmission/o.d and refilled with SAE 30. (I think gear oil was what I drained out). So what's the poop? Did I make an unpardonable mistake or does it make "no never mind"?
Thanks
 
The car's handbook & the Austin factory workshop manual specify SAE 30 grade engine oil for the 100 gearbox & overdrive. Until recently I have always used this in my BN1 but I have tried 75W90 Gear Oil with no noticeable difference. There has been much discussion on the forum about lubricants for O/D gearboxes. I currently use Penrite 40 Gearoil for our warm Queensland climate.
 
Do a search on the subject, it's much discussed.

Some use 30wt, others use synthetic: Redline MT90, still others use multi-wt. Any is fine, although you are about to hear some varying opinions about each...
 
30 weight non detergent is tried, proven and factory recommended. If you have an overdrive, heavier oils and detergent oils may cause problems. The gear oil you saw is typically used for gear boxes like the differential which uses 90 wt hypoloid.
 
Thanks for your help. I think I'll stick with the SAE 30 non-detergent, which seems to be the conservative approach. Thanks again.
 
Back
Top