what oil in Gearbox

I cannot find anything in the history but I'm sure this topic was discussed. What gear oil do you guys use? Multigrade or single grade? SAE90? something that does not foam I guess... I have a '75 MkIII but Commando gearboxes from every year should be more or less the same?

Thanks in advance for advice....

Josh in Calgary

I like Redline Shockproof Heavy. Yes, it's GL-5, and no, it won't hurt your yellow-metal parts.

Castrol VX80 Manual Gearbox.

Mick

Auto trans fluid has been found to work fine and less drag if one cares.
Otherwise the top end specialty oils as already mentioned.
After a rebuild its not bad idea to break in with cheaper oil
and drain soon - you'll see if carries out some swarf and darkness
you don't need the good stuff dealing with for the long run.

hobot

I have tried them all. Threse gearboxes seem to like a good basic 80/90 gearlube. I have had the finest syn oils and the gears just seem to mesh better with a good dyno like Lucas 80/90 Gearoil. My issue is not being able to find a straight 90.
As easy as it is to change this oil, there is no excuse not to. These are good gearboxes and I have no problem keeping good,clean,fresh oil in it.

Lucas EP 85/90 wt in my combat for 2 years and 1600 miles no problems so far.
Napa stores stock it.
Marshal

We had an extended forum discussion of this topic this past summer. Brian's got it right. Redline Tech Services recommends their Shockproof Heavy for dogged-gear vintage transmissions. This product, like all Redline products, has no effect on copper alloys under 150C. I switched to it on the basis of the forum discussion and was amazed at the difference in my Mk3. Smooth entry into first (always a struggle before), and all subsequent gears. Clunking disappeared. My Norton is now the smoothest shifting of my bikes, and the only one running the Redline product. The Victor is next.

Try it for a season. It's an impressive product.

ludwig said:

pvisseriii said:

As easy as it is to change this oil, there is no excuse not to. These are good gearboxes and I have no problem keeping good,clean,fresh oil in it.

Click to expand...

What's so special about these gearboxes that they need fresh oil all the time , while you NEVER change the oil in the gearbox of your car ??

I use Castrol MTX full synthetic ,SAE 75W-140 and have no problem doing 20 - 30 000 km on the same oil .
Maybe change it every 4 or 5 years ..

Click to expand...

Simply my preferance and opinion. How about you?

You'd be amazed at how much better your shifting would feel if you did change the oil in your car's gear box every 10-15K miles; you'd also notice that the same cog box would be quieter longer.

RS

There is a local auto gearbox reconditioner, he has lots of high mileage VW gearbox jobs to do, he told the dealer the gearboxs would not fail if they tried changing the oil but the dealer replied he would lose the warranty work as VW paid no questions asked.

Just had the gearbox oil changed on my car despite the fill for life claim at 60K miles.

Ludwig,

I believe the argument for changing gearbox oil, and fork oil as well, is that it protects against corrosion of steel parts caused by the gradual acidification of the oil and the presence of water in the oil. This problem is more pronounced in bikes that are used infrequently, and the oil change requirement is more driven by time as opposed to milage. When I rebuilt my BSA and Norton, both showed corrosion on parts at the oil fill line, where any water in the gearbox would lie. I saw similar corrosion in the fork internals. I don't know what the appropriate change-out period should be, but it is easy to do. I'm planning on a 24-month change-out schedule, which will occur at the end of the riding season this fall.

Yeah, I've always read that moisture accumulation is one of the big reasons for changing gearbox oil on a regular basis. I've also always been told that "oil is cheap, rebuilds are not" and I guess that has stuck with me, right or wrong.

On my first Norton I used to use 90 wt. hypoid gear oil, as recommended in the owner's manual. It seemed to work just fine but it sure was nasty smelling stuff. Ick. On my current Nortons I've been using Redline MT90, upon recommendation from one of the forum members here. It works well for me, but it's very hard to find locally so this time I think I'll just go to the car parts store and see what they have. It seems the GL5 vs. GL4 concern is a non-issue.

As for belt drive kit vs. oil change, well it's a heck of a lot easier to install fresh oil than a belt drive! (Especially if it's an RGM drive from what I'm reading here).

Debby

I think I remember changing the gearbox oil in my Commando once but I'm not sure.

I always had VW or Audi cars for 20 years after leaving Austin Rover, this included a diesel Audi 100 that did 250K before finally the oil light stayed on at tickover. Got rid of my last ever VW last year, one of the latest Passats, in 70K miles I had roadside recovery out 5 times of which 3 resulted in major repairs at the dealer for days and mine was not the only one.

Just before sliced bread became a big deal I had a Ford Fiesta with a German built gear box. I went to change the oil and found no drain plug. Shortly after I brought the car to the dealer and suggested that the gearbox/differential (same unit) may have been manufactured with a flaw (no drian plug), to which I was told that the unit was sealed for life, no service required, add only. The input bearing failed at 55K miles. When I rebuilt the transmission I noticed that all the bearings were galled and replaced them all along with the syncromesh rings, I would call the oil that I captured "fero-fluid". I drilled and tapped a drain hole, the transmission was working fine with 20K oil changes after 250K miles and 12 years service; the body with no service interval bio-degraded beyond safe passage at the 12 year mark.
Manufacturers are competing to deliver vehicles that require fuel, only, during the warantee period, and they are almost there, and after that they salavate for the expensive repair bills that this BS maintenance routien provokes; the government and the "greenies" are in part to blame for these extended intervals. Problems that arise from poor fluid management are STUPID, because they are so preventable.
May you never have a failed part in the middle of nowhere...

Changing gearbox oil regularly is a reality for anyone who rides their Commando in cold weather. Condensation builds up turning the oil an off-grey colour, obviously from condensation.

My riding season begins and ends at below freezing temperatures so this is a reality for me. I rode to work two days this week, both mornings were below 0C.

FWIW I change the gear oil in my car's transaxle every two years, which is at about 40,000km. It drains as an oxidized black goo and gearshifts are noticably better once it has fresh oil.

Oil is like any other engine component, additves wear out and need replacing.