Changed trans and diff oil in 67 Ford F-250.

[ryanschillinger]

Used Dino 80w90 in trans and diff on my truck. The diff oil didn't look all that terrible, but the stuff that came out of the trans was NASTY. I drove the truck around for several miles before the change but trans was barely warm. Diff was still cold and of course I used the extractor on the diff since no drain plug. Took forever but I adjusted the brakes while the molasses crept through the hose. Next time I'll take it out on the freeway to get it good and hot before doing this. Got the radiator changed out yesterday. I think this baby is ready for a trip to the dump or Home Depot or even cruise night again haha!
After changing the diff and trans oils I took a nice cruise down around the beach and stuff. Shifting felt much better but I only went a few miles. Like I said the trans oil was very bad looking. Next real drive I'll know if there was a real difference in shift quality. Not expecting perfection out of an old np435 anyway.

 

[Chris142]

Dont put gl5 in that trans

 

[JHZR2]

I'd do it again before too long if you don't know the history of the fluids. You have two things working against you here - time and the fact that you didn't get it to temperature. So I'd do both at least once more when you have a chance.

 

[ryanschillinger]

I did some research before putting the fluid in the trans. It's an NP435 4 speed granny first gear if that makes a difference. I used gl5 that said safe for yellow metals. I was to understand that would be ok. Am I wrong? I know the older gl5 was corrosive to yellow metals but supposedly newer formulations are buffered or something to not attack or corrode the yellow metals. The gear oil that came out of the diff looked pretty good. The trans did not. I should probably plan on another drain and fill on that.

 

[Greasymechtech]

Most GL5's from local auto part stores come premixed with LSD additive. Buffered or not, I don't want LS additives or GL5 rated fluids in a manual transmission.

Consider Amsoil MTG, Redline MT90 or :
http://www.amazon.com/Genuine-12346190-75W-90-Synthetic-Transmission/dp/B000QIR1V2
http://www.amazon.com/Genuine-Ford-Fluid-XT-4-QGL-75W-90/dp/B001H1I5Q2

 

[ryanschillinger]

It feels like it shifts 100x better but the old oil was really nasty. The supertech 80w90 says protects from corrosion of bronze and copper and stuff. Doesn't say anything about LSD additives. It also says it's safe for top off and refill of manual transmissions. I know that because I was concerned and dig them out of the recycling bin this morning haha! Anything to worry about? Seems like it's ok based on my reading. Novak page about np435 says gl5 is ok.