Home Transfer case work.
Moderators: Cal_Gary, T. Highway, Monkey Man, robi
Transfer case work.
I’m needing to replace both the front and rear output seals on my transfer case. From what I can tell it is the original np200 on my 52’ I’m not finding the manual that covers replacing the seals. Does anyone have a lead on what manual it is or even a pdf maybe? Also I’ve never done these on an np200 or anything like it before, am I correct to assume that the bearing retainers need to come out to get the seals out?
Re: Transfer case work.
Cal_Gary
1954 M37 W/W
MVPA Correspondent #28500
1954 M37 W/W
MVPA Correspondent #28500
Re: Transfer case work.
me too, my NP200 case seals, the ones on the rear of the case, are leaky, and I need to do new seals soon. My plan is to drive down to the auto craft shop at Ft. Jackson, near Columbia, SC, where they have lifts and tools and army trained mechanics to offer assistance. I have the TM's, and while I doubt anyone on active duty has current experience with these old trucks, I suspect the shops at the base have lots of general experience with replacing seals. I am going to ask Charles T if he has and will provide the newest seals and Redi-sleeves for me. I hope you comment on your own task, and even take pictures, so I am better prepared to replace my own T case seals. It seems to work well otherwise. I hope to do it without having too lower the T case, but if so, they have equipment for that too there. I have read everything on this forum about replacing seals. Good luck,
HC
HC
Re: Transfer case work.
TM 9-8031-2 (repair and rebuild manual for everything except the engine and transmission) and ORD 9 G-741 (parts catalog) are the manuals you need. Both can be found from various suppliers, but I find that the printed (not scanned on to CD) versions are the clearest and more accurate; I like the comb binding for use on the workbench. Portrayal Press sells them: https://www.portrayalpress.com/searchre ... 37&Submit=
Yes, you can replace the companion flange seals with the NP200 in the truck, and without removing the retainers. Not as convenient, but do-able. Use new production seals (not the OEM leather type), and put Redi-Sleeves or equivalent on the yokes to prevent future oil leaks.
Read through the manual section (Chapter 9) before tearing into the job to get an idea of the procedures, and the special tools you'll need (e.g. a torque wrench, something to hold the yoke when removing or installing the nut, etc.). Plenty of information on this forum about how guys have done this job.
Yes, you can replace the companion flange seals with the NP200 in the truck, and without removing the retainers. Not as convenient, but do-able. Use new production seals (not the OEM leather type), and put Redi-Sleeves or equivalent on the yokes to prevent future oil leaks.
Read through the manual section (Chapter 9) before tearing into the job to get an idea of the procedures, and the special tools you'll need (e.g. a torque wrench, something to hold the yoke when removing or installing the nut, etc.). Plenty of information on this forum about how guys have done this job.
“When a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, IT IS THEIR RIGHT, IT IS THEIR DUTY, TO THROW OFF SUCH GOVERNMENT...” -Declaration of Independence, 1776
Re: Transfer case work.
easy job doing the seals its re setting the pre load that can get tricky... better to file down a thick spacer than to rum multiple thin shims. speedie sleeves will work in a pinch but if the sleeve fails it will eat the seal in seconds. better to weld and turn your yokes or run two thinner seals or just space out the seal if doing it on the cheep.
.............................. use it ...............
Re: Transfer case work.
I've never had a Redi-Sleeve fail, at least not one that was properly installed. Have you had a failure of a correctly-installed Redi-sleeve (Timken) or Speedi-sleeve (SKF)?RMS wrote:easy job doing the seals its re setting the pre load that can get tricky... better to file down a thick spacer than to rum multiple thin shims. speedie sleeves will work in a pinch but if the sleeve fails it will eat the seal in seconds. better to weld and turn your yokes or run two thinner seals or just space out the seal if doing it on the cheep.
“When a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, IT IS THEIR RIGHT, IT IS THEIR DUTY, TO THROW OFF SUCH GOVERNMENT...” -Declaration of Independence, 1776
Re: Transfer case work.
with an upcoming knee replacement, it will probably be fall before I can actually attempt to replace my T case seals. But I have been studying the Power Train TM, both the written instructions, and esp the parts assembly diagrams. My main concern is if it is necessary (advisable, for sure) to re-set the pre-load with shims. On older posts there are pictures of broken shim rings. but if my case was working well before, and accepting the chance that bearing or shim wear is substantial, can I leave them alone, and tighten the big yoke nuts to the 140-160 # spec? And when I pull the old seals out, is there a risk that the bearings will come out too, and give me all sorts of parts on the shop floor? And is there some suggested way to pull old leather seals, Slide hammer/screws, screw driver, or else?
I will probably do this at the post craft shop, where they have army trained mechanics to help, but I doubt any of them have dealt with a NP 200.
I plan to do this with the T case in the truck. But if your collective advice is to put it on a work bench, and do it all per TM, then they have the jacks and such to get it in and out.
As always, thanks. HC
I will probably do this at the post craft shop, where they have army trained mechanics to help, but I doubt any of them have dealt with a NP 200.
I plan to do this with the T case in the truck. But if your collective advice is to put it on a work bench, and do it all per TM, then they have the jacks and such to get it in and out.
As always, thanks. HC
Re: Transfer case work.
Just pulling the seal likely won't cause the outer tapered roller bearing to pop out and fall on the floor.
The TM shows a special tool (41-R-2372-215) to slide in between the shaft OD and the seal ID to pull the seal. I've never seen one of these, and I've been collecting the special tools for years. A Miller corkscrew puller might do the trick. But I think most people use the old sheet metal screw and slide hammer technique, or in extreme cases, tack weld a stud to the seal body.
I always verify the bearing pre-load after re-assembly. Most of the time, the shim pack won't need to be changed, but do you really want to take that chance? And if you do gamble, you're assuming that (a) nothing has changed since the bearings were set up years ago, and (b) the last guy to do the pre-load did it correctly.
It's a lot of work to tear it back apart to change bearings (which aren't cheap) if they get damaged by the wrong pre-load. And if you have to replace the gear with shaft, well...Midwest Military has them available NOS, at $300 a pop.
The TM shows a special tool (41-R-2372-215) to slide in between the shaft OD and the seal ID to pull the seal. I've never seen one of these, and I've been collecting the special tools for years. A Miller corkscrew puller might do the trick. But I think most people use the old sheet metal screw and slide hammer technique, or in extreme cases, tack weld a stud to the seal body.
I always verify the bearing pre-load after re-assembly. Most of the time, the shim pack won't need to be changed, but do you really want to take that chance? And if you do gamble, you're assuming that (a) nothing has changed since the bearings were set up years ago, and (b) the last guy to do the pre-load did it correctly.
It's a lot of work to tear it back apart to change bearings (which aren't cheap) if they get damaged by the wrong pre-load. And if you have to replace the gear with shaft, well...Midwest Military has them available NOS, at $300 a pop.
“When a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, IT IS THEIR RIGHT, IT IS THEIR DUTY, TO THROW OFF SUCH GOVERNMENT...” -Declaration of Independence, 1776
Re: Transfer case work.
Ive never seen a speedie sleeve fail personally, however my buddy Terry worked for BC transit and said it was a common occurrence on the old Detroit powered buses.... granted they saw more miles in a year than most m37s have seen over the last 68 years.
.............................. use it ...............
Re: Transfer case work.
Well, thanks to the sage advice and experience of those who have "been there and done this", this fall I will drop it at the post craft shop, and do it correctly with their help and equipment. hc
Re: Transfer case work.
I never had a bearing fall out when replacing seals, during my Army tenure or afterward, and that number has to be in the hundreds, mostly on M-Series trucks serving on Active Duty, and on my M37 of course. Usually the biggest challenge is getting the big nut off; however, modern impacts usually take them off with ease.
Gary
Gary
Cal_Gary
1954 M37 W/W
MVPA Correspondent #28500
1954 M37 W/W
MVPA Correspondent #28500
Re: Transfer case work.
It isn't a job I would do in frame. That said, it is heavy and unbalanced getting it in and out. If you just pop the seals in and out and do not disturb the bolts that hold it together you won't affect the bearings and preload. You can't easily or correctly install repair sleeves in place. If you do end up taking it apart there are some precision ground hardened spacers the will shatter if you don't have them seated correctly when you torque to set preload. They are unobtainium and you will need to find a donor case or make them if you break them.
Depending on how bad the leak actually is would determine where I would go. If it is a drip or two a day, I'd leave it be. If it is pouring oil then I'd tear into it. The T-case is an expensive "while I'm in here" item.but once opened you might as well go all the way..
One last thing. There are 3 different yoke castings. Make sure they go back in the correct locations.
Another last thing. The operating shaft seals will REALLY be hard to do in place.
Depending on how bad the leak actually is would determine where I would go. If it is a drip or two a day, I'd leave it be. If it is pouring oil then I'd tear into it. The T-case is an expensive "while I'm in here" item.but once opened you might as well go all the way..
One last thing. There are 3 different yoke castings. Make sure they go back in the correct locations.
Another last thing. The operating shaft seals will REALLY be hard to do in place.
"It may be ugly, but at least it is slow!"
Re: Transfer case work.
thanks to all, and I will do just the seals after removal, with the help of my son and the mechanics at the craft shop. Later this fall. HC