1962 R69s Transmission Oil

[germancarguy]

What should I run in a freshly rebuilt transmission on my R69s. I know its does not have synchro rings, but it shifts like an old truck.

Paul

[schrader7032]

Can you tell us more about what was rebuilt? Parts...seals, etc. This service bulletin mentions what was changed during BMW's production to allow hypoid gear oil to be used:

http://www.beemergarage.com/documents/254.pdf

There's been discussion that if you're going to use gear oil, use a GL4 spec which doesn't attack yellow metals as aggressively in the transmission. I'm not necessarily in that camp, but think that GL5 oils could be use, especially if there's a low sulfur content.

[Daves79x]

Use GL4 synthetic. And they all shift like an old truck.

Dave

[r67boxer]

This is my preference.

And yes, they all shift like tractors, particularly from 1st to 2nd. Try pre-load shifting.

Kevin

[germancarguy]

Thanks All

The transmission and motor were rebuilt by the nice people at Barrington Motors in New Hampshire and I knew what to expect with the shifting because the transmission does not have synchros. Apparently I can't help myself from playing with the R69s, hence the question about the transmission oil. I started using Mobil 1™ Syn Gear Lube LS 75W-140 in my 2012 GS and it was a game changer, the difference took about 300 miles to really show itself. Since the R69s has all new modern seals and bearings I thought I would give the Mobil 1 a try for 500 miles and decide. I will also try the preload shifting technique.

Paul

[schrader7032]

IMO I wouldn't use something with a 140 in the weight...that's much too high and can create issues I would think. 80w90 is really where you should start. Not sure it tracks to compare a '12 GS to an R69S.

[Seek]

Avoid GL5. That stuff is really agressive. And there are quite a few brass parts inside your transmission.

[Slash2]

Proper technique can result in smooth, slippery shifting in well built transmissions.

As others have mentioned, preloading the shifter is essential and while many say you need to pull the clutch and allow the rpms to drop significantly for smooth shifting, I have not found this to be the best practice in my experience with many /2 era BMW’s. If it’s shifting hard and clunky, you’re doing it wrong. Proper shifting on these machines requires a finesse and technique unlike any other transmission I’ve seen but the result of perfecting this technique is greatly rewarding.

My procedure looks like this, light preload of the shifter, followed by clutch and a simultaneous release of throttle. There’s a split second of delay between these steps and therein lies the finesse. Experiment until you get it right. Never kick the shifter, always apply light pressure a moment before pulling the clutch and the gear should slip into position.

[germancarguy]

Point taken

I will take the bike out and get it hot then Drain the Mobil 1 GL5 and put in the Sta-Lube GL4 GEAR OIL 85/90.

Thanks
Paul