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cyberunlimited 08-31-2008 12:34 AM

1999 Wrangler Transmission Question.
Hello, I have a 1999 Jeep Wrangler with a Manual Transmission. I need to know the procedure for changing the fluid. How much does it hold and what type of fluid should I use. Should I use ATF or 90 Weight?


richp 08-31-2008 09:07 AM

I would us Redline MT-90, as for draining and refilling, there are two big 1" 'bolts' on the drivers side if I remember right, they are up high. Tip, remove the FILL or top plug first BEFORE you drain it, then remove the drain plug.
You are also going to need either a small hand pump that screws into the bottle to fill it or one of the suction/fill guns, they look kinda like a grease gun.
If you did not listen and can't remove the fill plug after draining you can remove the shifter and fill it from the top, PIA but do able.
You will need 4 quarts if I remember right, I normally buy it by the case and use as needed which is why I don't know off hand.
The transfer case is what takes ATF, for that I use Mobil-1 ATF.

jtraider 09-03-2008 11:52 AM

i had a question about this last week and got some really good advice. however, when i went to take the filler plug out, oil started pouring out. i hadn't removed the drain plug yet. is this normal? and if its coming out, does this mean that its too full or is there some pressure inside? also called the dealer to inquire about the mopar part number for the oil, and they said it was replaced with standard 10w30 motor oil. sorry, didn't mean to steal your thread.

Jerry Bransford 09-03-2008 11:58 AM


Originally Posted by cyberunlimited (Post 259881)
Hello, I have a 1999 Jeep Wrangler with a Manual Transmission. I need to know the procedure for changing the fluid. How much does it hold and what type of fluid should I use. Should I use ATF or 90 Weight?


The FSM specifies a 75W-90 with a GL-3 or GL-4 being fine for your '99 manual transmission. Do not use a GL-5 75W-90 which is all you'll likely find on the store shelves. As Richp recommended above, Redline MT-90 is a very good choice for your particular transmission.

Jtraider, 10W-30 motor oil is roughtly the same viscosity as 75W-90 gear lube so that works too, probably not quite as well as Redline MT-90 though. And if you removed the actual fill plug and not some other bolt, no, the gear lube should not pour out of the hole. What transmission do you have? :)

richp 09-03-2008 12:02 PM

Yea, make sure it was in fact the fill plug and not the drain plug. How this could happen though is the last person to change it filled it thru the shifter hole, you can do that by pulling the shifter and pouring in which case I would measure it, with the filling thru the filler plug you fill till it runs out just like the transfer case.

jtraider 09-03-2008 12:26 PM

The plug was on the driver's side and had a torx head on it. i believe i have the ax-5? also, my drain appeared to be dead center on the bottom towards the front of the transmission and has an 15/16 head. i didn't see any other bolts on the sides that even looked logical to be a filler hole. i had noticed that it look like i had a leak and when i looked at this torx bolt i could actually turn it with my fingers. i went ahead and bought a full synthetic 10w30 to put in but i wanted to check some things with you guys first.

Jerry Bransford 09-03-2008 12:28 PM

With the drain plug on the bottom, it definitely sounds like it's the AX-5 which is what you'd have if you have the 2.5L engine.

jtraider 09-03-2008 12:34 PM

do i have the correct fill hole?

Jerry Bransford 09-03-2008 12:35 PM


Originally Posted by jtraider (Post 260944)
do i have the correct fill hole?

I don't have an AX-5, mine is the AX-15 which is a little different, but it sounds like you do. Was your Jeep level when you pulled the fill plug?

Edit: Found this photo of where the AX-5 tranny's fill hole is on Stu's website... Jeep TJ Web Site of Stu Olson - N7QJP

sailsurf7713 09-03-2008 02:58 PM

Fill plug in a size 15 torx. Its on the driver side of the tranny. Drain plug is a large flattish bolt on the bottom more towards the back of the tranny.

Definitely recommend MT-90 over an engine or AT oil.

jtraider 09-03-2008 03:31 PM

Is that the one that says 'don't remove'?

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