Transfer Case Leaks

[WarrenD]

Over the last few weeks, I've been doing a lot of fixing on the M37. I found something interesting and thought I'd pass it along. Apologies in advance is this has been discussed before. During my driveshaft replacement, I decided to tackle the rear output seal in the transfer case. I had been getting a pretty good leak and it seemed that there was always a drop or two of gear lube hanging off the bottom of the t-case drain plug whether I ran the truck or not. I have been looking under other M37's at shows and have seen almost all of them with drops forming at the same location.
I started to get curious as to where the leak actually was as I had packed some absorbent material above the cross member (Depends for MV's) and I still had drops on the drain plug even though the pads were not soaked. I got the seal replaced and during the process, drained the lube (again). It didn't look like the seal was leaking all that badly but as long as I was in there, I replaced it with a neoprene one. Shaft was good, not a mark on it, nor any wear grooves. When I put the drain plug back in, I decided to try a few wraps of teflon tape around the threads. After several days of sitting and some running, no more drops forming at the drain plug. I suspect that these plugs either weren't the greatest or/and over time they have gotten sloppy.
So, if it looks like you have drops from the drain plug on the t-case, a little teflon tape might be all you need!

[hbb]

If they are not leaking they're out of oil! I have chased leaks on older transmissions and transfer cases for years and sooner or later they will leak again. Oil was cheep and repairs expensive and machining tolerances were not what they are today due to different oils and additives.Teflon tape is a good quick fix for the drain plug.Some of the cover bolts at the flanges and side covers can use a sealer on them to help tame it down for awhile, I have had the best luck on those using liquid Teflon sealer,But a common concern is the use of Teflon tape on fuel lines or hydraulic lines,The Teflon can and will come loose and block critical passages and cause serious damage.Some of the best gasket sealer I have used is a product called Honda bond and that is available at Honda dealers, permatex has a similar product that is a gray silicon sealant that also works very well.When you talk to a room full of technicians they will each have his or hers favorite sealing tips and procedures so with that said good job!

hb

[WarrenD]

Thanks for the info, hb. I know these things will leak, and I assure you I'm not obsessed with plugging every little leak but when I can identify a major leak and the fix is easy, it seems like a no brainer. I'm very careful where I use teflon tape and won't use it on parts that have flow (like the fuel and brake lines you mention). In the case of the T-case drain plug, I didn't wrap the entire plug, just toward the outer end leaving a few bare threads at the start. Sometimes I'm smarter than I look!

[hbb]

Warren what I had posted wasn't meant to piss you off but as information and I had no intention of questioning you ability's or mechanical aptitude. I was just in a shop that a journeyman technician was using tape on everything including fuel lines so you learn not to assume anything about anyone. as far as obsessing about the oil leaks I have a client that is doing just that with his vehicles a M37, M274, and British Ferret which leaks like all British vehicles do and i dont seem to have enough oil dry around for it!but as he has told me that these are fine show vehicles that should not be leaking! so as it goes some folks do obsesse about oil leaks.

[WarrenD]

hb,
I didn't take it that way at and I'm not pissed about anything. I know it is hard (impossible) to determine someone's mechanical aptitude (or IQ for that matter) over the internet. I appreciate your reply, thank you for taking the time to post and if I came across as being terse, I apologize, my response was supposed to be more lighthearted and humorous (again, things that come across better if you know me or we were talking). No harm, no foul on this end!

[MSeriesRebuild]

Fellows, it isn't normal to have leaks on any component on the truck. You can build components that don't leak, although you may not be able to stop the dripping the way mentioned here. We have built many cases up from scratch; with everything clean and using premium quality sealing products, it isn't a problem to build up a drip free case that will remain drip free. Most that we build go out with Royal Purple 40 weight synthetic oil in them, contrary to the popular belief of many, that won't leak either if you build it right. We never use teflon tape on anything.

[hbb]

Warren
Your absolutely right, is tis impossible to properly judge ones personality in print! your apology is accepted and extended to you! Our forum is where we receive and share information of mutual interests and I learn different ideas,facts of specifications and general knowledge all of the time from the forum and its guy's like you and I that we get that Information from. Thank you for your input

hb