Hello everyone! I am working on my 1992 F-150, 5.8L EFI, 4x4 automatic with E4OD 4-speed. The truck is all original as far as I know, and has 260k miles. My first post with a lot more info about the truck can be found here ------- https://www.f150forum.com/f12/1992-f...1/#post7627874

I am currently working on changing all the fluids in the entire truck. I have been researching fluid types for days, and am finding a TON of conflicting information, especially when it comes to transmission fluid. I'd love to get everyone's input on what exactly I need to use...


Engine Oil ----- This is the only fluid I have changed so far. I used Napa 10w-30 full synthetic high mileage, since it was on sale (see pics of oil jug below). I'm assuming the oil is fine, but my question is mostly about zinc additive... This engine has flat tappet cam and lifters, so should I be adding zinc? Very conflicting info online about this...

Transmission Fluid ----- I plan to drop the pan, change the filter, and drain the converter (it has a drain plug). My truck is missing the owner's manual unfortunately, but pics of the manual I found online say to use Mercon II / III, which looks like it has been entirely replaced by Mercon V. That's all fine and dandy, but from things I've been reading, a lot of people say to use Mercon type-F. I'm having a hard time figuring out what exactly the difference is.

Transfer Case Fluid ----- It was my understanding that I should just use the same Mercon V in the transfer case, but then I see a few posts that say Mercon V is NOT TO BE USED in transfer cases and will ruin them... Well what should I use then? Also, the transfer case was low, so I already topped it off with Mercon V... I haven't driven it much yet though, so hopefully no damage done?

Power Steering Fluid ----- I was also under the impression that Mercon V is to be used here as well, and I topped this off with Mercon V the other day as well... Then I see posts saying not to use it, and to use power steering fluid specifically... Aren't they basically the same thing?

Rear Differential (axle code 19, 3.55 open diff) ----- Fill plug is rusted, haven't been able to get it loose yet to check the level. But when I do go to drain and replace it, any advice on what oil to use?

Front Differential ----- Same question.


Thanks very much everyone for taking the time and giving me your input! Vehicle fluids have always been confusing to me because of so much conflicting information online... I'm always terrified that I will use the wrong fluid and blow something up.

 

owners manual info

 

Thanks. Unfortunately, the owner's manual did not come with the truck, and I haven't purchased one yet. As far as what I can find online, things seem to be conflicted. I did find that the power steering fluid is apparently supposed to be Type-F though...