Gear & Trans Oil - Synthetic OK on an '89 K75?

[technostructural]

Hello All,

I feel that I may be opening a can of worms here re: the dino vs. synthetic debate, but I have a question about the appropriate gear and trans oil to use in my 1989 K75.

I read at Ted's House the following quote that made me think twice about using synthetic:

"BMW apparently redesigned portions of the final drive, especially the spline material and seal design of the final drive in 1991. Some owners of pre-1991 bikes have reported synthetic oil getting past the final drive seal and entering the swingarm so the choice of going with synthetic is entirely up to the individual owner. On post-1991 bikes synthetic oil is recommended in the final drive."

I don't live near a BMW Dealer, so, like many of you I'm left to what is available at my local auto parts store. I figured I'd go with this stuff, as it seems pretty reputable, but I wanted the opinion of Motobrick before settling on anything.

Lucas also makes this 75W140 stuff that looks like it would do the job nicely, and I have read that folks have used 140 weight oil without too much trouble.

What are your thoughts? Is there a "go to" gear oil that Motobrickers use, or is this left up largely to discretion?

[johnny]

greetings...

i use 75w90 cause its close to the oem 80w90...

lucas oil makes some fine products... i would not hesitate to use lucas oil products...

there has been much talk abouts the 75w140 causing final drive bearing failures... seems like bmw issued a service bulletin that mentioned using 75w140... there was an increase in fd failures... some think it was the 75w140 causing it...


my 1st fd failure was at 140,000 miles... had been using castrol 80w90...


my 2nd fd failure was at 103,000 miles... had been using mobil 1 75w90... the last change was made by a independent bmw wrencher at 100,000 miles...


i gave him 75w140 for the gear box and 75w90 for the final drive... he put the 75w140 in both... i know this because he told me 1 bottle for both and returned to me the full 75w90...


he showed me the service bulletin on his computer... he wont do that again...


royal purple at canadican tior...




j o

[technostructural]

Thanks Johnny.

Any comment on the synthetic v dino issue?
Should that be a concern?

[Gio]

Canadian Tire also has Motomaster brand semi-synthetic 75/90 that's GL-5 ... I had some left-over from using in the Subaru and think that should also be ok for final drive (my supply of MG 80/90 with moly is dwindling).

For the trans - I'm on the hunt for a local supply of Red-Line Shockproof light (75/140) otherwise will use a 75 or 80/90 in there also.

Gio

[F14CRAZY]

I've had my bike for about 10k miles and have run Supertec (walmart) synthetic blend 75w90 and no leaks so far. The previous owner also ran that stuff

[technostructural]

I've had my bike for about 10k miles and have run Supertec (walmart) synthetic blend 75w90 and no leaks so far. The previous owner also ran that stuff

Sounds like this stuff should be fine then. API Class, GL-5, SAE 80W90 -- and it's cheap and easy to track down!

[K75RT Keith]

Use whatever make you happy.  As long as it is changed with some regularity (either miles or months) it won't matter.

[richarddacat]

Don't forget to add the Guard Dog  :2thumbup: 


i fixt your link there cat... it was whack... j o

[technostructural]

Don't forget to add the Guard Dog  :2thumbup: 


i fixt your link there cat... it was whack... j o

I wish that stuff was easier to get my hands on! I requested a quote from Guard Dog to see what it would cost to have that shipped to me, along with some Guard Dog 525 for the splines. Kind of a bummer to spend nearly $80 for lubricants...

[Gio]

I hear you techno ... came to the same conclusion re GD shipping to Canada, but was able to source Honda Moly 60 (for spline lube)  from amazon.ca which included free shipping.

Gio

[Snowman]

Mobil 1 Synth for 120K in trans and FD, no probs. I feel the hoopla about synth oils getting past seals is over rated and if your seals are that bad then dino oil would get passed them shortly thereafter.

[Gio]

There was also similar discussion re synthetic in MG final drives a few years back, so I stayed with 80/90 dino there - not so much for the "leak-past the seals" reports, but mainly for the moly-factor. Red-line SPH synthetic in the MG trans however is widely regarded as improving shift quality - and does in my own opinion - but I have no experience of anything other than 80/90 dino in the K trans.

If in doubt - stick to the specs I would say.

Gio

[enb54]

I too have used the Canadian Tire Motomaster brand semi-synthetic 75/90 with the Honda Moly 60 in my K100 and now in the K75, so far no issues, and the fellow who bought my K100 at 150,000 Km put another 60,000 Km on it with no drivetrain issues. The Moly 60 I got from the local (Turple Bros.) dealer... I do change the lubricants every year, so that is likely a big help...

[mw074]

Many K bikes and many oil changes. No problem with synthetic for gear and trans. Just change it when you should. Some people recommend changing it every other oil change. I change it every oil change because it is easy. Comes out as clean as it goes in.

[K75RT Keith]

The closest relative to a K-Bike Power train is an automotive power train.  No need for fancy oils in the engine and a decent quality gear lube will keep the trans going just fine.  A gear lube with molybdenum improves shifting (for some) and reduces wear on the gears.  As I said before the big thing is to change the oil and lube an a regular basis.  Either months or miles, what ever makes you happy.

Weakest link isn't the lube in the trans, it is the splines on the shafts.  Those definitely need a grease/ lube with a high molybdenum content.  and definitely need to be checked about every second rear tire change or 20,000 miles.     

[K1300S]

I just changed my final drive and trans oil.  always use Redline stuff in my BMW race cars so went with Redline 75w90 in the final drive and Redline MTL in the trans.

[kris]

Techno,
The dollar exchange rate is killing us right now. The charges when I bought GD were nowhere near that. Remember, you don't need that much. And as for changing gear or tranny oil every oil change or every other....man, that is overkill by a thousand, in my opinion. Check some of the specs or research on theses lubricants. Kendall is producing a synthetic gear oil for buses/ commercial and industrial use that is rating at 500,000 miles! Don't know about you but I ain't running my bike that hard so I think the oils will stay put a little longer. I will go with Beemer's shedule on that.  Synthetic shouldn't break down due to moisture, etc., like dinos so you should be able to extend change intervals. Anyone else want to weigh in on this?

[enb54]

A really good (although a bit self serving) article on synthetic lubricants is at http://www.synlube.com/synthetic.htm . Although it is a long read plus a plug for their product, they have captured the essence of what "synthetic" really means. By the way, I do not work for or sell their products... Plus, I personally use Mobil 1 and Castrol Syntec...

[jjs1234]

A really good (although a bit self serving) article on synthetic lubricants is at http://www.synlube.com/synthetic.htm . Although it is a long read plus a plug for their product, they have captured the essence of what "synthetic" really means. By the way, I do not work for or sell their products... Plus, I personally use Mobil 1 and Castrol Syntec...

So after reading the article...


So what then? Most oil mfg's use "synthetic" as a marketing term? This Syn-Oil website (looks like the website was built in the early 2000's) sells oil @ $30 a quart!

Why dont you buy SynLube if its the only "real" synthetic oil out there? Claims to "50,000 Miles for every oil change."

What about Guard Dog? They claim to "Friction decreased 26%" in their synthetic engine oil additives...


Who do people trust?

[F14CRAZY]

A really good (although a bit self serving) article on synthetic lubricants is at http://www.synlube.com/synthetic.htm . Although it is a long read plus a plug for their product, they have captured the essence of what "synthetic" really means. By the way, I do not work for or sell their products... Plus, I personally use Mobil 1 and Castrol Syntec...

So after reading the article...


So what then? Most oil mfg's use "synthetic" as a marketing term? This Syn-Oil website (looks like the website was built in the early 2000's) sells oil @ $30 a quart!

Why dont you buy SynLube if its the only "real" synthetic oil out there? Claims to "50,000 Miles for every oil change."

What about Guard Dog? They claim to "Friction decreased 26%" in their synthetic engine oil additives...


Who do people trust?

K's seem to last long enough regardless of what oil is used in them...change it regularly and I don't think it'll matter much

[enb54]

A really good (although a bit self serving) article on synthetic lubricants is at http://www.synlube.com/synthetic.htm . Although it is a long read plus a plug for their product, they have captured the essence of what "synthetic" really means. By the way, I do not work for or sell their products... Plus, I personally use Mobil 1 and Castrol Syntec...

So after reading the article...


So what then? Most oil mfg's use "synthetic" as a marketing term? This Syn-Oil website (looks like the website was built in the early 2000's) sells oil @ $30 a quart!

Why dont you buy SynLube if its the only "real" synthetic oil out there? Claims to "50,000 Miles for every oil change."

What about Guard Dog? They claim to "Friction decreased 26%" in their synthetic engine oil additives...


Who do people trust?

K's seem to last long enough regardless of what oil is used in them...change it regularly and I don't think it'll matter much

I agree, even though I use a less expensive synthetic, if you change your lubricants at regular intervals, you'll never have any problems. I got into the habit of using synthetic in our cars because they start better after sitting outside for a long time in cold weather, and it just became a habit...