• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

tranny lube

Share this page

fmichaels

fmichaels

Jedi Knight
Offline
so i dismantled three ribbed trannies with the same results. major wear and tear. i am ordering replacement parts. is there a recommended assembly grease that would be compatible with the tranny oil?
 
Is tranny oil not the same as engine oil? I think so for our cars.

Use the same stuff you use to assemble an engine if you wish or just plain oil. Heck you are going to fill it with oil in any case and it does mix in there fast.
 
i thought tranny oil was a 90 weight oil? anyway, putting the needle bearings together and assembly in general requires some form of a grease or assembly grease i believe. makes assembly easier i guess.
 
Although 90 is often used, the original oil spec WAS 20/50, the same as the engine.

When I rebuilt my box, the people that supplied the parts recommended synthetic 90, so I used that.
 
yep, gives you a bit of sticky.

Assume that is a ribbed box 1275 tranny. Engine oil. check the book.
 
i'll check the book and then i'll look for a gen purpose assembly grease. thanks
 
is anyone aware of any previous threads on the pros and cons of 20/50 vs 90? after seeing the consistent wear/tear on these trannies, it would be nice to know what works best (i.e, the original manuf. recommended oil or what most of us use).
.
what are you using jack?
 
Yes, there have been a few threads on the subject. A search should bring up a few of them. I personally have always used and would go with the factory-recommended engine oil ratings rather than 90wt, which is much too thick for these gearboxes.
 
After 40 years with no maintance and everyone and his brother learning to shift on it tis no wonder they look bad.

I ran a unrebuilt smooth box from 1975 to about 1990 almost every day to work, son drove it to high school, daughter learned to drive with it. No problems with box ever, always used engine oil. Castrol bought by the case.
 
for older, rib-case or smooth case transmissions (with BMC "A" engines), the recommended oil is regular motor oil. 10W-30 works fine as will straight 30 weight or 20W-50.

For the Triumph-powered 1500 Midgets, the recommended trans oil is different (these cars use the Spitfire/Marina all-syncro trans). Gear oil such as 90 weight or multi-weight gear oil is recommended. I use 90 weight synthetic in my 1500 racer...works better than regualr gear oil as far as shifting.
I am building a 1275 engine with rib cage trans. In that trans I'll use 5W-20 motor oil.
 
okay. 20/50 then. i am researching assembly lube as well. i may just use a gen purpose engine assembly lube.
.
just a note: from the smell of the tranny cases (all three) that i took apart, i believe they had 90wt in them.
 
I think that is a rather common mistake made with rib-case and smooth-case trannies, and may well have been a factor in the rough condition of the three you have taken apart. The thicker lube may have contributed to the rougher use on them in attempts to get them to work right!
 
well since i am replacing everything that matters, i will go with the oiginal recommended oil. the car will not be a daily driver and knowing the wear first hand will ensure i take good care of this one.
 
I have used both and found that the best performance and shifting was using 20W50. I did recently add eight ounces of Lucas oil stabilizer and based on the results would recommend it. When running the 90W there were problems with shifter lockup and the tranny would get so hot you could not hold your hand on the metal shift cover.
 
I have always tried to use 30 wt NON-detergent oil for my trans whenever I could. The detergent stops the foaming and the oil foam is what lubes the moving parts in the upper sections of the trans (as well as splash). Remember that detergent stops foaming, that is why you dont use "soap" in the dishwasher (try it, it's kind of funny until clean-up time!! )
Bill
 
90w or 90-140 or 85-90-120 or GL5 or GL4 rated oils are HYPOID OIL and are completely different from motor oils.

In a ribcase trans you use MOTOR OIL. 30w or 40w if the trans tends to leak.....synthetic 40 if you choose and if the external fiber washers and screws dont leak, as the synthetic migrates faster thus leaks more.
 
Back
Top