jobofly

Hey Guys, i have to change my rear end gear fluid soon, is this very hard to do? i have usually taken it in to have it done but am trying to save some money, thanks

Joe

whitecrystal1

It's not hard at all. You have to unbolt the cover since there is no drain plus so be sure and get a big drain pan. After you get the cover off make sure you clean all the silicon off both, the cover and the differential housing. Then apply some new silicon and bolt the cover back on. I would give it a few minutes to let the silicon set up but it may not really be necessary. Once the cover is back on you need to remove the fill plug, it's on the other side near the drive shaft. Then fill it until the oil starts coming out the fill plug. Note: If you have a limited slip rear you will need to add one bottle of friction modifier.

I just did mine a couple days ago. Mine required 2.5 quarts of 75-140w gear oil (9.75RP-12bolt). I choose to replace the cover with a Mag-Hytec cover while I had it off, it increased the oil capacity to 5 quarts it also gave it a magnetic drain plug, dip stick and a port for an external temp gauge. For fluid I decided on Royal Purple, it has the right amount of friction modifier in it already so there is nothing extra to add.

hollowjacket

84 f150
4.9ltr 300ci
inline six
hydro clutch
2wd

I have to do the same thing, but the fill plug is seized on, what should I do to get it off. I don't want to remove the whole housing, because fear that I will have to replace everything, being all seized up. I just want to get the fill plug out, stick in a small hose hooked up to my outboard gear oil pump and suck out the old fluid and replace the same way then put the fill plug back in.
How do I get the fill plug off? Can I apply a torch to heat it up or is the fluid dangerous around heat?
Also, I will need to change the U-joint, is this an easy job to do, could someone detail the procedure and what I will need please please. This truck is a beater just for work, I only paid 840 for it, so I am not planning to put a lot of money into it, that's why I'm so cheap, I'd rather not take stuff apart that has been together seizing for the past 24 years to open a can of worms.

Oh, I got the alternator all done and wired using 10 gauge wire and using 2 14 gauge fusible links side by side to the solenoid, it works great!! The alternator is rated for 65amps, so 2 14gauge fusibles should be enough.I hope!!

Chris

Good old Bill

Never thought of outboard gear pump thing. Don't be affraid of the torch idea either. If still can't get it off, whitecrystall's suggestion of cover replacement has merrit. U-joint replacement is easy but can be frustrating. Make sure to prepack bearing cups with a little grease to help hold all those nasty little needles in place. Sometimes if u-joint has a zerk fitting remove it before disassembly to allow for more sideways movement.

whitecrystal1

That is a very good question you brought up. Anyone attempting to do this should try to remove the plug before removing the cover, so they don't find themselves in a situation where they find they can't get the plug out after they have the cover off

I still have to service my front differential. Your idea on sucking the old fluid out of the plug hole sounds like a very good one. No need to fix something that ain't broken and since I'm not replacing this cover, I might as well do that instead of taking it off.

jobofly

wait, theres a new cover that i can get that has a fill and drain hole? how much and where?

whitecrystal1

Here you go There are others that make them too, but Mag-Hytec seems to be the better choice with what their covers have to offer over the competition. Plus Mag-Hytec's covers have the largest increases in oil capacity than any other I've seen.

My guess is you have the 8.8RP 10 bolt cover but check your axle code first. This cover increases the oil capacity to a total of 4 quarts.

If you shop around you can find them for right around $200 (ebay). I bought mine along with a Mag-Hytec double deep transmission pan shipped for $375. Lucky for me, I bought them off someone that bought them new but never installed them.

If you are more after a looks kinda thing at the same time Oasis actually makes a cover that has a 150 logo available on it. It does increase the oil capacity more than stock (+1 quart) but not as much as Mag-Hytec does (+2.5 quarts in my case). It also comes with a magnetic drain plug but I can't remember if it has a dip stick or not. Mag-Hytec's dip stick is magnetic. There is no extra port on the Oasis cover to add an external gauge if that is something you may consider. I found on ebay the Oasis covers can be had for the same ($200) cost that the Mag-Hytec covers are going for.

Oasis's covers looks nice but Mag-Hytec's covers has more to offer.

jobofly

ok cool, thanks for the info, now when you say silicon, is there any certain kind?

whitecrystal1

RTV silicon or equivalent.

jobofly

ok thanks for your help