elm

I don't think anything is as tough as an old mack. Specificly the DMs, but I doubt they'd fair well as far as safety goes. On the other hand, I've seen more than one International get totalled in accidents that I don't think would have done much but maybe crack the hood on one of my Rs. I watched an international 5600 with a 10 yard box hit a moose head on at about 45 miles per hour. Missed my truck by about 10 feet. Smashed the whole cab up pretty good. Whe I asked her if she was OK, she said, "yeah, but what did I hit"

And the front cab mounts just stay the same?

anyone ever convert an old R series to Air ride cab? I've seen a kit or 2 available but would love to get some real-world info first. I'd be installing it on a 1989 R600. its already got hood rollers, an exhaust stack that doesn't mount to the cab, and the radiator supports go to the frame, not the cab, so I believe all that's left is to add the replace the rear cab mount with the proper bracket/air bag. I know you guys like pics.... but for some reason I've never been able to successfully upload a pic to a forum. I have no idea why. (I get error code -200)

Yup, you gotta have spare parts. Specially if your remote like I am. I've got 3 runners and 3 for parts. Oldest is a 74 newest is an 89. Plus there's 1 in the local scrap yard. I find my self yanking something off a parts truck a few times per year. Just yesterday it was a bent air can mount. And almost a differential🥵anyone else out there got one with a Detroit engine in it? All mine are 672 mack engines except 1 has a 6v92 Jimmy. It's a total pain to work on it. It doesn't fit real well.

I should have came here first. Would have saved me alot of time! No worries though. The dump bed comes off easy enough, and the rest.... well, it was a good learning experience. I'm finding not a whole lot of people know much about these old dogs any more. I love them though because I drive almost exclusively off road, and you just can't kill them. And no electronics. You can work on them. In fact, besides a book for the 672ci engine, I never even had a shop manual. And I've got 5 trucks. Never needed a book before. Well... at least I thought I didn't lol

Wow. I'm surprised I've never known this after driving these trucks for almost 20 years. I should probably go check my other trucks. I bet they've all got to much oil in them because I've always checked and add if needed to both top and bottom housings. Lesson learned. At least it's an easy fix. I just found out the hard way. Thanks for all the help!

Interesting..... so how does the oil get back up top after it splashes down? Cus my lower housing (the pumpkin) was Way way over full, and the top was way low. That's normal? Maybe I removed the dump box and pulled the whole thing apart for no reason. I live in a remote town and have literally no mechanics to ask localy so I just jumped in head first.

Well, besides the wheel seal, I don't see an obvious leak. Before I pulled the top case off, I drained about 4 gallons out of the lower housing. (The pumpkin) about twice what it should hold. And the top rear housing (the one on the large aluminum access cover) was so low I could jiat barley touch the oil with the tip of my finger. This can't be right. I don't see how fixing the wheel seal will fix the main problem of oil leaking from top to bottom. I don't think it matters in this case, but I'm working on the rear rear so no lockout mechanism.

hello, new here. My 79 R600 recently developed an oil problem. a few weeks ago, it blew out a rear wheel seal. I pulled it into the shop and found the top gear case (the carrier housing) to be very low on oil. I filled it back up and continued hauling for a few more hours to finish up a project. the next day I checked the diff fluids again, as it leaked a lot out of the bad wheel seal and found the carrier housing was low on oil again (after only a few hours of driving and sitting overnight). the lower case, was over full by quite a bit. I was in the middle of an important job and needed the truck for a few more days, before I could tear it apart, so I ran it a few more days, and each day, the top case was low a quart or two, and the bottom was over filled. It has no other leaks besides the wheal seal. I assumed there was a bad seal in the carrier housing, so I removed it and can't find anything wrong. infect it appears that right about at the level of the fill plug, there's a hole that connects to the other side (passenger side of truck) that is open to the bottom housing. so, I'm not really sure how it wouldn't leak down. The only other thing I found, was that all the bolts that mount the top housing were nice and tight except for the 3 hard to get ones were snug, but not very tight at all. including one of the ones inside the cover. if that bolt were crazy loose, id assume that was my problem, but I just can't imagine losing a quart or 2 of 90w day through a snugged-up bolt. I don't see any obvious cracks, and the vent wasn't plugged. I'm kind of stumped. I hate to put it back together without fixing anything. Its leaking bad enough, I expected to find an obvious problem, but I didn't. Anyone have any ideas? is this common? I've been running Macks for almost 20 years, and this is my first time ever having to tear into a rear end. although I have noticed it does seem like they normally VERY SLOWLY loose oil from the top into the bottom.