I am not a fan of throwing away perfectly good oil, but in my Vette and the wife's Honda the factory oil life monitor is telling me to go 9000 miles or so which seems like a long time.

Thus, on all my vehicles I have done Blackstone oil analyses with TBN information to see how much additive life remains when I change the oil. In each case, they advised to stretch my oil changes out a bit as my oil had plenty of additive life left which ends up saving me money. I knew that 3000 mile thing was just throwing good oil away so I gave up on that plan long ago.

Has anyone done the Blackstone TBN analysis on their transmission and primary oil? Doesn't seem to me that those oils would need replacement every 5,000 miles given the use of the fluids - there are no combustion byproducts to taint the fluids. I've never changed any automotive transmission fluid every 5,000 miles.

Problem is, the analysis at $35 is more than the oil change costs (I do them my self).

I'll probably do it the first time I change the fluids in my 60,000 mile EVO just to see what shape my components are in, but thought I'd post up a thread to see if anyone has done the analysis and what their results were.

I searched before I posted so if you plan to just type "do a search" I did and didn't find the info I seek. Thanks in advance for any pertinent information.

 

Newer Harley's have 20k service on the Trans.

 

Transmission every 20,000
Primary every 10,000

 

When it comes down to it, oil is cheap.

Use common sense, change oils and lubes at or before recommended intervals.
pay attention to aspects such as severe duty- like in AZ we have dirt and dusty conditions ( always) and sometimes very high temps.

Short cycles, failure to fully warm the machine can also be very, very hard on the oils, causing acids and moisture to collect in the cases.


A motorcycle that is used a few times a week for 20 or 30 miles a trip, will likely be in better shape than a bike that is used for occasional rides around the block


Mike

 

I totally agree with you on the short rides harming engine oil....but my question is since the transmission and primary oil do have have the combustion byproducts (acid), I just don't see that they need to be changed every 5000 miles like my 1995 manual states.

That's why I started this thread to get ideas on that, as well as, hopefully find someone who did the analysis so I can save the $70.

 

Every fall the engine oil/filter and primary gets changed regardless of mileage. I will probably do trans every 10k, but that's probably overkill.

Unfortunately, the conditions for my duty cycle won't match yours. Apples and oranges. Mine at 10k may equate to yours at 5k. IMO, spend the 70.00. cheap insurance

 

interesting

my mercedes benz manuel says 10k to 16k for the engine and NEVER change the tranny and it will last 300k ..ez

 

Yea. I always had trouble leaving my engine oil in my Benz for over 10k, but never had any issues. But also remember our MB's take 9 qts of oil. Just that tends to stretch it out a bit.

 

The primary doesn't have the combustion by products as you mention but it will have suspended particulates from the clutch and chain tensioner wear. Also it is subject to the same acid formation due to moisture as the engine oil. The transmission is subjected to far less particulates but the shear is much higher from the gears. The primary oil is always cruddy looking when I dump it while the trans lube generally looks just like it did when it went in. The cost of the analysis is just about the same as the cost for the fluids so my thought is just change it as scheduled and be done with it.