I give up ZEB, you don't seem to be able to understand comparing Weights between "engine oil" & "gear oil" is the same as comparing apples to oranges.

 

While we're here... I thought about using gear oils also, but worried about clutch slippage. I have a Toyota Tacoma with a 5-speed that had lots of synchro/gear clash when using Mobil 1 - so I went to Red Line and that's been fine.

Has clutch slippage been an issue with anyone? Or is that just with engine oil (because of the added friction modifiers)?

I'm not sure the HD synthetic has anything extra for gears except the zinc for the engine. My guess is that it's a neater marketing solution to be able to offer one fluid for all, and it doesn't hurt the gearbox (but might not be optimal).

 

Hey buddy, why don't you give it a rest. If you will happen to notice what the other fellow said in how he's using an Bel-Ray 85-140 gear oil in his bike, this oil is definitely aTHICKER, HEAVIER, HIGHER VISCOSITY OIL THAN HD's 20-50 COMBINATION synthetic motor and gear oil.

And it's things like this that are the reason as to why I started this post, to try and find out why some others are using such a HEAVIER oil in their trannies.

You've said your piece, I've read it over and over,now let someone else post and talk about what I started this thread about in the first place.

And BTW, just for the record, 75-90 GEAR oil has a higher real viscosity than 20-50 weight motor oil, no matter how you might try to slice it. It's a HEAVIER oil.

 

I've wondered the same thing about clutch slippage and drag with the synthetic. So far since I've put in the 20-50 synthetic, it seems to be working okay, but it has yet to get real hot around here yet.

 

I once had a 1997 883 Sportster. I started off using the recommened Sports-Trans-Fluid. While I was having it serviced....a gentleman convinced me to use diesel 15w40 for both holes. He stated that he had great success with it in his 1200 Sportster and he also claimed it had around 50,000 miles on it.

I thought about it long and hard about that switch. I decided to put diesel 15w40 in the crankcase and the primary/transmission. From about 10,000 miles all the way up to 80,000 miles....it had 15w40 in it. It never burned any oil and the clutch acted like it was suppose to. In other words, the nothing was ever torn apart.

The current owner has roughly 120,000 miles on it.....he bought it from me and is doing the same thing with 15w40. He has yet to have any trouble.

15w40 is probably not the best stuff and is probably not recommended either. There are probably better stuff out there that should be used. It was just something I was talked into....now I am glad I did it.

 

actually I was going nuts tring to figiue out different gear oils also. I spent time here and on xl forums and to see what others use. I don't think the H-D sports-tran is a 75w90 gear oil. even the people at the H-D dealership can't tell me.I thinks it's a 80w gear oil. when the H-D dealer put n 85w140 I asked him if it had any moly or fiction modifiers in it, and he wasn't sure. Mobil 1 DOES have some moly in it and I didn't have a problem with it. I contacted Bel-Ray and askes them and they told me that the 85w140 DOES NOT have any friction modifiers in it. they also told me that the 85w140 was not recomended the the sportster and to use thier 85w transfluid or thier new sports transmission fluid.
I look at it this way, the 85w140 does not have any moly or friction modifiers in it, the gear noise is better. so I will change the gear oil the same time I change myengine oil every 2500 to 3000 miles any I think I will be fine.

 

Remember this, "Keep it simple, Stupid". Engine Oil can be used in the Tranny, but the Tranny Oil cannot be used in the Engine.
There is evidence that the Sport Tranny fluid is actually 40 weight motor Oil.

 

Man, just use what hd recomends and call it a day. Big deal if you get a little nois, or a clunk or two.If you change the fluids as required, you will never have a problem. I will use the sporttrans until my dealer runs out of stock. Then I will switch back to 20/50 motor oil, that I stared with ,as stated in my service manual ,and change it when I change my engine oil and filter. I buy penzoil 20/50 for $3.50/ litre. Spend the money you save on fuel to ride with, and who gives a rip about whaht oil you decide to use. Nothing will improve performance that you can feel so why waste your money . That's just my opinion...Mark...

 

Sorry Zeb, the 90w gear oilis the same Viscosity as 40/50 Motor Oil. editied to add Sport Trans Fluid tested out to be 40 weight oil

 

I need to chime in here a bit, ,,,,, because....... I just had both my oils changed at a different dealer this time because they also just did my new pipes/airkit/and download, so i figurred i would have them give me all new fresh oil.....

I told them to use Synthetic, becasue my original dealer changed me over at my 1000 mile service......


But now i have this intermittant whinning sound thats coming from what it seems to be in the gear case....i cant tell what side its from..... and it comes and goes.... I'm not sure if its a bearing thats going, or what the hell it is.... i cant even prove it to the dealer,becase when i get back to them it stops.....go figure.....


so i wonder....i think i read on the work order,,,,, spot trans..... NOW, did my first oil change at my dealer use syn engine oil, and now the new dealer that i used has this sport trans stuff in there...... could it be the clutch slipping like i read on this thread......

i may have to call my original dealer and try to find out what they used, becasue i may switch back if thier is something else in it now....

anyone ever have this.......also ,,,, the noise happens in 2nd sometimes, 3rd sometimes and 4th sometimes......strange
jim