MAT4Ret

1996 F-150, 4.9L, 5 speed manual Transmission.

I am confused about the type of oil in the transmission. To my suprise thin reddish automatic transmission oil came out the fill when I checked the level. I thought sombody had made a real mistake but when I referenced the owners manual all I can find is Automatic Transmission fluid fo "5 speed OD Transmission". I checked auto parts stores and the refrence regular gear oil. Automatic Transmission fluid just does not seem correct.

frank5079

Yup...A/T fluid is what the M5OD gearbox takes.

BareBonesXL

This chart is handy although it starts at 1997 for F150's. If your 5 speed tends to get hard to get in to gear at times like many do, Synchromesh seems to work better than the Mercon V AT fluid. I use Synchromesh in mine and it made a big difference. I tried the Mercon V and the Synchromesh was much better. Somebody else on the forum recommended it.

I have some barely used Mercon V that I'll sell you for cheap.

http://www.carquestprofessionals.com...0%206.6.13.pdf

MAT4Ret

I thought this was a stupid question so I have been doing an exhaustive search but nothing absolute so I decided to join this forum; glad I did. Now I will be hooked. The reason I was looking was that I just had my 4.9 L rebuilt, then I had a slow drip from the font of the transmission. Took it back and they replaced the rear main seal...Still leaking. A friend told me to make sure it was not over filled. It was right at the top of the fill but what came out was thin reddish oil. I don't think the leak is fixed but now have a great resource thanks to you...

justintendo

atf is indeed the correct spec...however a thin viscosity manual transmission lube is a much better choice. atf has a very weak anti wear package, but is the correct viscosity. redline has an lv manual transmission lube that is excellent. i am using redline power steering fluid currently, and the shift action is fabulous. its quite the rabbit hole when you get into manual transmission lubes concerning atf. the suggestion using synchromesh fluid is along these lines, altho it is a bit thicker. it does have the proper additives for synchro friction coefficient action, that atf lacks. check out "bob is the oil guy" to learn about this. there are many options better than atf here, just stay away from gl5 spec oils...these are a different animal. gl4 usually means safe for manuals, but not always.

frank5079

I've been using Dexron full synthetic ATF in my gearbox along with Lucas ATF additive, but I have toyed with the idea of using Shell Rotella 5W-40 full synthetic just because I've used Rotella 15W-40 in my old Suzuki RF900 and now use in my Vmax and was amazed at how much it improved the shift action and feel of the bike, which was clunky before....

Steve83

This chart & those linked in its caption are specific to these trucks:


(phone app link)

Your trans is called "M5R2" in that chart (first column).

You should put all the truck's details into your signature so you don't have to remember to describe it every time you have a question, and we don't have to dig back through a thread to find if/where you posted them.


(phone app link)

justintendo

engine oil does not have the needed friction modifiers for synchro operation, which is not a consideration for motorcycles. rotella does shift decent in bikes, but automobile trans synchronize much differently. try some redline lv 70w/75w manual transmission gear lube. it is very close in viscosity to atf (around 6.5-7.0 cst@100 celsius) but is actually built for a manual transmission, something which atf and motor oils arent.

the redline power steering fluid im currently using my 96 150 is not advertised for manuals other than stating "satisfies 70/75w gl4 requirements"..it is however built with the same additive pack their manual gear lubes are and shifts great with identical feel cold or hot. the newer lv 70w/75 they now offer likely replaces the ps fluid for tranny use.

justintendo

here is some excellent reading about the differences in transmission lubricants...and the puzzlement of why manufacturers keep speccing atf in a manual.

https://www.bobistheoilguy.com/forum...ts#Post1231182

Pacificsvt