1999 XLT 4x4 automatic, 3.0 v6 with 4:10 standard differentials.

I'm looking into servicing my diffs and transfercase. Ive learned that the diffs take 80w90 gear oil, and the transfer case takes ATF. However, according to my manual, it raises a question. It specifies 'mercon atf'.

Would 'mercon atf' indicate any mercon from 1 to 5 or just and only standard mercon? I've also read this is to be serviced every 60,000 miles.

As for the diffs, I was unable to find a service interval for these. That too is something I'd like to be aware of.

And one last question. What is the easiest way to get fluid back into the diffs/transfercase? transferpump, little electric pump, etc?

EDIT: Doing some research on my own, and answers are all over the place. Some say use mercon v, some say dont, some say ford says dont, some say ford says go ahead, holy guacamole.

 

The current Mercon V ATF is what Ford now specs, it is not the same as the "old" Mercon V ATF that was used years ago, it has been changed so it now works with older parts that used Mercon ATF

I use a hand pump that screws on to most quart bottles, all auto parts stores will sell them, not expensive, but does require a bit of pumping.
If I had a fleet of vehicles I would probably go with electric pump, but I don't and I am cheap :)

Go here: https://www.ranger-forums.com/genera...1-models-3747/

See if the 1999 owners manual has the service intervals, it should

Rear differentials on 4x4s often had limited slip, you need to add a friction modifier to new oil or get oil with it already added, if you have L/S
Front never came with L/S

Look here to see what you have: Ford 7.5 & 8.8 Inch Axle Tag & Door Codes

Get your AXLE code and look it up

 

I've got a couple quarts of ATF Mercon V on my shelf, along with a screw on bendy straw type attachment, so that should work fine. Might take a little wiggling but it'll work.

Unfortunately 1999 isn't listed there. 2009 is, and it recommends the fluids in the diffs be changed at 150,000. Which is likely what I'll go with if the fluid proves to be clean.

Looks like I'll get to use my new impact, though! :)

I think I'm going to have to dig up my service software. I've got it somewhere, just have to find it and install it. I swear, most of the info I have to find should be in the manual to begin with.

Thanks again for your info.

 

1996 to 2011 manuals are there

https://www.ranger-forums.com/rf/ran...nuals/1999.pdf

But didn't see it in there, yes 100k-150k

Also long as the Mercon V was from 2006 or newer it will be fine, thats when Ford redid the formula I believe.

 

Ford actually sells Transfer Case Fluid and don't suggest using Mercon V in them. Heres why...


As for the diffs I have a mighty vac fluid extractor that works wonders on the front diff since theres no real easy way to do it. Rear is straight forward, make sure the fill plug will come out first, then pop the cover. Be ready for some stinky stuff.....gear oil smell is not easy to get off your skin!

 

Well, so far my transfercase is still in one piece. Must be a long fuse, lol.

I'm satisfied Mercon V will suit it just fine.

 

Im sure it will. Ive only changed mine out once and Id think the factory fill was mercon V. I found the Ford transfer case fluid at a local chain parts store that has a lot of OEM fluids so I put that in it.

But yea, look up that fluid extractor by Mighty vac. Ive found I use it for a lot of stuff. Works great on lawnmower/small engine oil changes, changing power steering fluid, brake fluid, etc. Pretty handy gadget....runs off the air compressor. Its ideal for the front diffs in Rangers since theres only one plug it get the fluid in and out.