front differential lube

flyfisher · 03-03-2013, 11:15 AM

Sportsmobile recommends changing the front axle lube every 20,000 miles. In the 55,000 miles I've put on my Van, I've put about 100 miles with the front hubs locked in, maybe 100 miles. As long as the lube level is where it's supposed to be, is it really necessary to change the front axle lube?

thanks..

Tom

Zeta · 03-03-2013, 11:54 AM

I changed mine at 50k, after much use, and it looked new.

Z

**daveb** · 03-03-2013, 12:05 PM

Maybe they over recommend this just for insurance sake. On the first run I changed it at 1000 mi because it was new. I normally replace the fluid about every 40K but I do use my 4x4 quite often. Also, I'm in and out of water on a constant basis. If you are driving through a stream, a warm diff can absorb water according to the experts (even if the vents are high). You also have to think about metals. Anyway when I asked SMB the same question they said no, if you don't use the front axle, you don't have to replace it as often.

BTW I broke in my diffs according to the recommended methods.

**BroncoHauler** · 03-03-2013, 12:35 PM

My unofficial, sometimes I follow it sometimes I don't rule, is that I change the front diff fluid, rear diff fluid, transfer case fluid, transmission fluid at 30,000ish miles regardless of how they're used. For me, if I have different fluid change periodicities I know I'd let one go far too long.

Herb

carringb · 03-03-2013, 01:01 PM

Another consideration is condensation. The rear diff gets hot enough condensation cooks off. Unless you drive at highway speeds for a good distance in 4x4, the front diff will never get warm enough to start cooking off the condensation that has been building up. Dry or warm climates probably not a big deal. Cool and damp like the PNW this can be an issue.

cellularSTEVE · 03-03-2013, 11:01 PM

I changed my last week. It was relatively easy to do and low-cost. So you may just consider to do it anyways.

steve

MadScience · 03-03-2013, 11:17 PM

Side-track: I was under a land cruiser the other week, and noticed that they had extended the diff vents to hoses that vented fairly high up in order to keep from sucking water into the diffs during fordings.

I don't think I've seen that done on a van.

geoffff · 03-06-2013, 10:15 AM

Quote:

Originally Posted by carringb

Another consideration is condensation. The rear diff gets hot enough condensation cooks off. Unless you drive at highway speeds for a good distance in 4x4, the front diff will never get warm enough to start cooking off the condensation that has been building up. Dry or warm climates probably not a big deal. Cool and damp like the PNW this can be an issue.

Highway speed in 2WD with hubs locked also would do the trick, I presume.

An hour at 70 MPH definitely expanded my front diff fluid -- it came out my breather tube.

-- Geoff

flyfisher · 03-06-2013, 09:36 PM

thanks all, for the tips. I'm sort of OCD about taking care of The Van. In the colder months when I'm not using it much, I always take it out for a 20 or 30 mile ride once a week, just to keep things moving. And once a month I turn the front hubs in for 5 miles or so to slosh the lube around in the front diff. I think the lube will be good for more than 20k miles.

Tom

Roonie · 03-07-2013, 09:52 AM

Quote:

Originally Posted by MadScience

Side-track: I was under a land cruiser the other week, and noticed that they had extended the diff vents to hoses that vented fairly high up in order to keep from sucking water into the diffs during fordings.

I don't think I've seen that done on a van.

I extended my diff vent hose into the engine compartment and made a loop with it pointed down so no water can enter it. With the SMB 4x4 system engaged it can throw oil up the vent tube at highway speeds. This was the only way I could find to minimize this occurance. I also changed my front diff at 30k because it had thrown some oil over time and I wanted to be sure it had enough in there. It was relatively easy to do.... hardest part was getting the bolts loose and the cover off. The oil that came out looked used and I was glad I did it but the 4x4 system is actually used here a lot so it makes sense. Also there was plenty of oil in there. The little that gets spurted up the vent tube looks like a lot but in reality it is minimal.