well, to add my
, i just rebuilt my transmission, and put lucas 85W90 high performance in it. After driving it around the block a few times and just rolling it out of the garage, and even just running the engine for a while, I have decided that the transmission DOES NOT LIKE this oil one bit. Its been spitting it out everytime the truck runs. At first i just figured the oil level was a little high and it was righting itself, but after checking the level many times, ive concluded that this should no longer be happening. I was reading the bottle of oil and it says it has EP additive, and "gear climbing additives" . You know, like those little clear boxes with the gears in it and regular oil on one side and super oil on the other at the parts store....well I think this might be the problem and the oil is "climbing its way right out the input shaft area. Thats what brought me to this thread and after reading the entire thing, i have since called back to the house and had one of my minions drain the oil out for me so i can put SAE50W diesel engine oil in it. I do read TMs and have done so for many years. What ive gathered from this thread, and some research i did myself, is that if Spicer recommends SAE50 over 85W90 then by all means im gonna use SAE50....reason being, they built the **** thing, they would know what works. As for the TM and all this GL-1 GL-5 hoo-haa, The TMs are not the almighty god of trucks, nor is the manufacturer. If you say well, the manufacturer said that years ago when they had crappy oil, this new stuff is soo much better... well yah maybe it is...but DID YOUR TRANSMISSION CHANGE AT ALL since the manufacturer made said statement? I think not....And the TMs as i read somewhere are just a compromise for expediency...I know that for a fact, having been in the military as a truck driver, ive seen TMs handed out, taken back, revised, rescinded and redone at least 4 times for one vehicle while i was there. So..to recap, TMS arent always right. Manufacturers arent always right. TMs arent always wrong, Manufacturers arent always wrong. But for me, if the manufacturer said to use SAE50 because thats whats close to what they used BACK THEN, then thats what ill use...my transmission sure hasnt changed since it was built so....just saying. SAE50W for me.