I have an 86 F350 with a T-19 manual transmission. I’m looking to change out the oil in it and can’t seem to come up with a solid answer on what will work the best. I read that you need non-hypoid gear oil but I can’t seem to find any. Then I read that any 80w-90 will work or 50w engine oil.

https://www.autozone.com/greases-and-gear-oil/lubricant-grease/p/lucas-oil-products-80w90-hd-gear-oil-1-quart/693858_0_0?

can I fill it up with this or should I get 50w motor oil? If you have any suggestions on oils I’m all ears.

 

80W-90 as you get some hot weather. If it shifts poorly in the winter, try the 50W.

https://www.novak-adapt.com/knowledg...anual/t18-t19/

Look for an oil that mentions compatibility with synchros.

 

no worries about the gl5 rating eating up the yellow metal?

 

Apparently "newer" brands are not as bad as the older stuff. It's a little confusing. But if the label says ok for synchro, I suppose they don't put that on there to be cute. Product liability being what is.

 

Yeah that’s what has been messing me up. I’ve been reading info on the internet that’s been ranging from the last 20 years. I guess stuff changes over time. thanks for the input.

 

after looking on redlines site it looks like that gear oil is too slippery for the T-19.

https://www.redlineoil.com/75w90-gl-5-gear-oil

I’ve been digging around the redline site and I think this is the one I’m going to go with.

https://www.redlineoil.com/mt-90-75w90-gl-4-gear-oil

 

I would recommend the cheapest (GL rated) 80w90 from your local farm supply store. All modern GL5 oils are safe for yellow metals, allegedly. MT-1 is "safer", allegedly. Its not a racecar.

Novak seems to agree: "An 80W-90, API-GL5 or MT-1 rated fluid is very good. Some claim faster shifts from using a 50W engine oil in their transmission and we do not consider this to be contraindicated unless you operate your vehicle in a very warm environment."

Both Mag-1 80w90 (Family Farm and Home) and Traveller 80w-90 are GL5, MT-1. I use Mag-1.

https://bobistheoilguy.com/forums/th...ission.278374/

The linked thread has a video in it. Worth a watch. People on the internet argue about lots of things without citing anything more than anecdotes or farmers knowledge. In this case, both will keep you safe, and lighter in the wallet. Hard to overcome the inertia from many years of "horror stories" on yellow metal damage, which pervade regardless of current chemistry and likely stem from early-internet forum posts.

I rarely, if ever, have seen a poster speaking from personal experience on the yellow metal matter (not to mention, recent personal experience). YMMV. Redline is good oil. Cant go wrong.

 

I agree 100% you can read a thousand posts about the horrors it does to yellow metal but rarely hear about people rebuilding a trans because of it. I went with redline I don’t mind spending a couple extra bucks on something that a manufacturer makes specific for the application I’m using it for. It gives me peace of mind, one less thing to worry about. Thanks for the input.