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My transfer case is leaking quite a bit. It appears that the fore and aft seals are the culprits. The thing that really strikes me as odd is that my T98 doesn't leak whatsoever, not a drop. On the opposite end of the spectrum, my transfer case leaks like a tipped over can of oil.
Does the transfer case require any special tools to work on it?
Fred,
It requires a socket to fit the nut. The front output and the rear are the same size nut (if memory serves) and the seal is the same. It takes about 2 hours to do the seals. The only hard one is the input.
The reason that your 200 is leaking, but your 98 isn't has alot to do with the cooling of the 98 versus the cooling of the 200. 200's tend to run hot and melt seals. You might want to flush the 200 a bit while you got it apart to get any rust out, and that is rumored to make it cool better.
If you have an impact wrench, then the seal replacement is a breeze. If not then a cheater bar helps as the nuts have to be torqued to 200 (I think).
Seal part nubmers:
National #450308 all 3 are the same.
Hope this helps....and is right.
-B.
The e-brake also helps to hold things still while you loosen and tighten the nuts. Otherwise, be sure to block your wheels so you don't wrench the truck over your legs.
Hey Brian, thanks a lot for the information. Gee, I wonder if anyone has ever tried to adapt a transmission cooler into the NP200 to help it run cooler. Do you think that that would be feasible?Quote:
Originally Posted by Brian.....Sisson
Thanks, Barrman. Yes, wrenching an M715 over your legs would be a very bad thing.Quote:
Originally Posted by Barrman
The proper torque is 140-160 lbs foot.
The cooler idea has been thought about for a long time but no one has come up with a cheap way to pump heavy weight gear oil around the system to do it.
Plus heat is a symptom of a problem...one my t-case suffers from while some of them dont...there is an underlying problem, probably bearing clearances hat need adjustment, maybe combined with slop in the internal gears that, if corrected, would be a much better soluton than to run a cooler...treat the condition(s) that is really causing the heat...my opinion...
brute4c
Fred, I had to buy a 1 5/16ths socket (Craftsman) to take the yokes off, but the problem was that it didn't fit inside the yokes and I couldn't get a grip on the nut. I took it to a friend and he machined .05 inch off the outside of the socket and it worked like a charm. When you put them back, the torque is 140 -160 pounds.
I measure work by how many beers it takes, so my adivce- stop in at the Kum & Go for an 18pk just to be safe.
-G-
YUP, inch 5/16's is the socket and you'll need to put it to the grinder just a tad to get it to fit into the yokes. If you don't have impact access, drop the front driveshaft, take a 1" piece of pipe and bolt that into the yoke so that it bottoms out against the frame when you're losening the rear on. On the rear, you may need to chain the pipe to the bottom of the frame. Doing this will prevent the truck from moving and about the time you've got real good pressure on the breaker bar...running out of room. Pipe in yoke works great!!
I'm gonna guess you guys are using 1/2 inch drive sockets....I used a 3/4 inch drive socket when I did mine, no grinding was needed on the socket...just fyi...
brute4c
I used a 3/4 drive Craftsman socket - required grinding the OD.
I happened across a photo in a completely unrelated topic showing a Tilton brand electric pump used to circulate gear oil through a cooler to keep a diff cool. Probably not a cheap option, but apparently there is something designed for what we need.
On the note of cooling, I got a response from Chuck's Trucks (they use the 200 in their corny rockwelled trucks). According to them they never have heat problems unless the oil is too low. Of course they probably don't spin the same rpms as us for extended trips and I bet those trucks don't see much freeway use.
Chris
I only have trouble with heat when I am above 50 miles an hour for more than an hour in the hotter parts of the year...in the dead of winter, I dont think I have ever seen the gauge get over 150.
The diff pump and other pumps used in industry for heavy oils, can be gotten for a bit of cash...then theres a cooler and lines and whatever you need to run it and hopefully a thermostat so you dont try pumping gear oil when its -20 degrees outside and the stuff couldnt overheat if it wanted too...the whole drivetrain is noticeably held back by the heavy stuff in all the gear boxs and diffs at temps below 0...I run 75W-90 Eaton synthetic lube. Since many have reported that they have run 60 MPH or more for hours at a time, it seems that the expense and work that go into doing a cooler would be better directed to correcting the discrepency in the case that causes it to overheat...less to screw up in the long run and less to haul around...plus it would be stock, if that matters, instead of modified to try to band aid a problem...then also there is the long term viability of using a pump/cooler instead of removing the problem causing the heat...will to tight bearing clearances or other problem(s) in long term use cause problems that will eventualy cause the t-case to need a rebuild or a change to a different case, like a 205 or something...if it is rebuilt correctly, as has been shown by several members, the cooler/pump would be unnecessary...if a 205 or other was used, same story...
Like in Apollo 13....Lets work the problem people!!
brute4c
I wholeheartedly agree Jon. I know in the past though there has been much discussion about not having a dedicated gear oil pump available. But apparently there is one.
I haven't seen any thorough documentation showing what exactly has been done to "correctly" rebuild the transfer case. Since mine is ready to be reassembled, I'd like to see what others have found.
Chris
About a hundred million years ago I posted a very ideal oil pump that was compatible with the temps and oil we have. It was from Grainger and was not to expensive. You would just need a way to drive it. I think it had a 1/4 inch shaft.... It was on the old site way back when. I was bored at work one day and wandered through all the catalogs we carry...
You can get the seals at auto zone
There's a really good step-by step reassembly section in the on-line manuals.