So I have this 82 F150 that I got 3 weeks ago. Needing to change fluids. I haven't worked on vehicles ever and this is my first rodeo. Please bare with me if I ask questions that I should know the answer to. The truck has the 4.9 inline six and the t-18 manual transmission. What weight oil is recommended for this engine at this age and what should I use for the transmission fluid? I ask about the transmission fluid because I saw that someone on here used motor oil before and then was told to use an automatic transmission fluid.

Thanks, Mark

 

I asked the same question some months ago. I had good sucess with diesel 5w40 in my 4.9, and it almost stopped the loss/seepage I was experiencing from the pan gasket. Many run 10 w 30. Many say you can run anything in that engine and not kill it! Diesels with more zinc may be better for our flat tappet 4.9. I am simply parroting what I've read here, BTW.

One of many discussions in the oil and lubrication forum.

https://www.ford-trucks.com/forums/1...what-type.html

 

The granny 4 speeds all use gear oil to my knowledge, and I would use 85W 140 instead of the 80W 90 the manual likely recommends

 

You have to watch when using diesel motor oil.
NOT all of them have high zinc because new diesels now have cats.
They also don't have as much anti-foam as a diesel dose not turn the RPM a gas motor does but the 300/six does not turn too high either.
A good high mileage oil (should have more zinc)in a 10w-30/10w40 or 20w-50.
Think I bought 10w-40 for mine for when I go to start it.
Dave ----

 

I am old school 80w-90.
Now there was a post on watch the label as some of the newer gear oil is not kind to brass parts inside.
Dave ----