Ok,
In the late fall of 2009 I changed out all my fluids for storage with 3100 miles on the odo. I put 75w-140 synthetic gear lube into the transmission. Last year was a busy work year and only put on 3000 miles. I left the tranny oil as is. I now have 7000 miles on the odo, with a total of 4000 miles on the 75w-140 syn lube. I am going on a 2500 mile trip in a couple weeks and do have new lube to change out the trans fluid. That said, what are some opinions/thoughts on leaving the current lube in for this season (will probably have about 9k miles on that lube by year end) or changing out to fresh with the current miles I have on the lube? It's not about being a cheap SOB but more about useable miles on gear lube...

 

No oil change in about 18 months?
I'd change it for sure, at least the engine.

 

Trans oil is fine, but the motor oil can become contaminated w/ fuel and combustion by-products, so change that.

 

Sorry, should have been clearer. Primary changed once since then and engine oil 2x. Just my tranny lube not changed since november 2009

 

I change my transmission oil (Redline Shockproof) every two years, regardless of miles. Considering a gear lube like you're using lives 5-10 years and 75-100k miles in truck differentials, I'd say you're perfectly safe in leaving it in there till your next scheduled change at the end of the season.

 

Run it.

 

Well, when I was changing my motor oil yesterday I went ahead a changed my tranny oil. Out came a clear golden yellow fluid with its original nasty gear oil smell. Pretty sure it was still within viscosity specs. Yep, I'm sure I could have waited but now I'll see if their's any difference with GL-1 rated Amsoil 20w-50. It will stay in 2 years/?? miles for sure.......

 

If I'm reading correctly you put 20-50 in the tranny? If so, I'd be interested in hearing if you notice a change in finding nuetral and shifting.
I noticed an almost immediate improvement switching to Amsoil 75-90 gear lube.

 

Weird thing is that both Mobile 1 and Amsoil recommend their 20w-50 oils in the transmission over their 75w-90/75w-110 gear oils?? I'll be going on a 3k mile trip here in a couple weeks so I'll be interested too.....

 

Troop: You can run the gear oils 15-20000 miles or 3 years in a HD trans. The redline tech says the shockproof heavy will go 30,000 miles. I change my trans every 2-3 years...no issue. But I do inspect it for any water.