Periodic/Preventative Maintenance on the 4x4 System

[djvanyel]

So I didn't see this topic covered anywhere, so thought I'd poll the group:

I've seen off-hand mentions of things that should be done to the driveline when a car's been sitting in storage a while. Since my '83 can now move under her own power again and is about to emerge from 10+ years in "stasis" in the dealer service department, I'm checking off the last of the "things to do" but haven't done anything with any of the driveline parts. After sitting for so long (and given the mileage), I would think some of the gear oils should probably be refreshed, but I've read that opening the differentials to change the fluid can be highly invasive, making it not seem like a "routine maintenance" item. I have yet to obtain a copy of the TSM to see if there's any mention of it, but thought maybe someone here could shed some light on it. I'm a firm believer in "if it 'ain't broke, don't fix it" but I also don't want to lunch anything on the road because of a simple maintenance item that got lost in the ages and wasn't done.

Thoughts?

[mo.eagles]

I did not change fluids in my car when I got it from PO and I'm now rebuilding the front diff. It had a little water in it . Maybe condensation IDK, but it was enough to trash the bearings. You have 10 bolts and a gasket so it's not extreme. Check your vent tubes also. Around here mud daubers love to plug that stuff up.

[vangremlin]

You have 10 bolts and a gasket so it's not extreme.

I didn't think it was possible to remove the cover from the front diff unless you dropped the front axle assembly out of the car.  There just isn't a whole lot of room there!

[eagleman]

Yeah if you got the front diff cover off without dropping the front axle assembly please tell us how you did it. When I changed the fluid in my 86 wagon I used a 12 volt vacuum pump and some step down vacuum hoses. Only way I found to do it.

[JayRamb]

I have a vacuum suction cool thingy, and I sucked/vacuumed out the fluid and I replaced it!

[amchornet]

I think there are only 5 bolts and you can loosen the front axle enough to get the cover off,

[macdude443]

Best way is to drop it and remove the cover completely.  This way you can fully inspect the gears and clean out any sludge.

I put the front on ramps, disconnect and tie up CV axles.  Remove driveshaft at front yoke (the shaft will sit neatly on the exhaust out of the way).  There are 5 bolts total.  Two going down into the diff from the drivers side motor mount (hardest to get to)  I used a few extensions to get a socket down through the manifolds to the bolts, 5/8" I believe.  Two more bolts below near the yoke and one bolt on the passenger side.  Lower it with a jack, being careful not to stress the vent line which is secured near the vapor canister by a sheet metal screw.  It's maybe 90 pounds.

I suppose you could leave the one bolt on the passenger side installed but loosened to act as a hinge.  That would keep it lined up and make it easier.  Disconnect axles will have a vacuum line or two near the passenger side you'll want to watch out for.

[mo.eagles]

You guys are right, I deserve this beating . My diff is on the work bench so I didn't even THINK about it in the car . When mine goes back in it will have a drain plug . IDK if it will be in the cover or bottom of diff housing yet .

[vangremlin]

No beating required.  Just wanted to clarify for those undertaking this job that it is a somewhat involved project. 

[amcfool1]

hi, changing front diff fluid in an Eagle has always been, and always will be, a PITA! Here is what i did. first of all, if the car has been sitting for 10+ years, you DEFINITELY need to change the fluid. Just from condensation, no movement, air, etc, is is probably very contaminated. This is true of ALL your fluids, brake fluid, oil, power steering, etc. I recommend you flush/change them ALL. But this post is about the front diff, so here goes. I'm in the middle of an 84 Eagle resto., had the front axle out, pulled the cover, and a bit of old fluid (probably from 1984!) came out, along with an ungodly amount of brown goop, dirty and chunky. Remarkably, diff is still OK. Anyway, I cleaned it all out. Sorry, the best (only?) way to do this is to drop the front diff out, take cover off, drain, clean, refill, reseal with new gasket, torque to spec, and reinstall, basically a weekend project if you have a friend helping and you supply the pizza and beer! Now, how to make this easier in the future? You are on the right track with wanting a bottom drain plug. Heres what I did. I purchased a Dana 30 diff cover from www.yourcovers.com. PML. Not cheap, but real good USA made quality. It has a bottom drain plug. But.. will not fit the Eagle as is, it;s too tall. I had it machined down about 1/2" , mostly the fins, now it fits but,, no access to the front fill plugs, so I had a hole drilled and tapped (NPT) on the PASSENGER side, to use as a fill hole. All is good now.! BTW< change your rear diff fluid as well. this is a lot easier.good luck. gz

[carnuck]

I'm swapping out my front diff, but I'll have a drain plug in the new one, figure out how much it takes to fill after draining, and make the breather into a fill tube too. I thought about adding a dipstick that can be put in when not driving to check it.