g741.org

Rebuild or reseal? My t-case.
My t-case it leaking badly and its noisy (but aren’t they all) its not metallic noise its just a loud humm at 50 mph. I cant really afford to rebuild it right now but if that’s what needs to be don then my truck will just have to be “down” for a while. What I want to know is should I reseal it or rebuild it? It is all still tight so I don’t think there is anything wrong with it except the seals are bad. It also never had any water in it; it had good oil in it when I got the truck and it only had 4k miles on it. so what do you think?

Going by your description I voted to reseal it. But...
Assuming your going to pull it to do the job, you might as well give it a full inspection while you have it out, and partially apart.

i plan to "look" it over really well

Which seals are you planning on using, nos or new material?

whats ever i can get .
do you know of a good place to get them?

http://www.midwestmil.com/index.html
I know Midwest has nos ones.

http://cgi.ebay.com/ebaymotors/ws/eBayI ... MEWAX%3AIT

I see this guy on eBay has a transfercase bearing and seal kit. He offers nos or new style seals. Not sure where he is sourcing his seals from.
Hopefully someone else will chime in.

If you plan to use NOS seals, don't bother doing anything, it will be all the same difference as NOS seals are worthless. Most likely you have rust pitting on the shift shafts and all 4 companion flange seal surfaces. Installing the very best new seals will not stop the leaking if it mates with a pitted surface. Never been any water in the case; don't fool yourself, you are talking about a 60 year old case that was once in military service, to think no water has ever been in that case is a myth. It really is not a big deal to remove the 2 rear drive units from the case to inspect it, most likely a fair portion of the leaking is coming from gaskets as well as oil seals. If rust pitting is present as it is in 99.9% of these cases, a rebuild is the only way to address the issue and get a good result.

I'm not casting a vote in your poll. Now that you have enough hard facts to base a wise decision on, you can approach it however you see fit.

The seal # is National 410308, redi-sleeve # is 99212, the shift shaft seal # escapes me at the moment, I can post it on Monday if you need it. All are available locally, no need to order in and pay freight.

Let me rephrase that. am a where that there probably was water in it at some point but it had been sitting under a car port for 14 years before I got it and I meant that there wasn’t water in it in that amount of time. The impute shafts are fine no pitting. You can see that there is no seal left on a few if the seals so I think that’s where the leaking is from. Obtusely I will take it apart and inspect it and replace what is bad but I just don’t want to have to replace everything right now.
and i do thank you for the knowledgeable and objective opinion.
i will take it apart and go threw it before i make my decision.

Those nos seals sure do like to hold moisture.
Great info on those interchange #'s Charles. Will come in handy when I get to my transfercase inspection. Thanks
Good luck on your inspection Bubba! Hope you find all is well.
Keep us posted on what you find.

The NOS seals with that felt preseal is the worst seal one could possibly install. That felt wicks moisture like a magnet, so even if the truck is stored under cover, it will stay wet from humidity, etc. It just sits there and stays wet, this is why rust pitting is a major issue on almost all. The same seal with the felt was used on the transmission output shaft, pitting is always a major issue there also. You could be fortunate if someone was smart and got rid of the NOS seals years ago.

Ok i took it apart and it looks good. There is minimal (I mean you can't even really tell its there and you can't feel it) pitting on a few of the gears teath. So I think ill be just replacing barring and seals and call it good.
i will not be useing nos seals. thanks for the part #'s ill go to my local timkin and see what it will cost me and get it don next week.

One thing you will need to do is set up the pre-load on the 2 output units brgs. This is an important step since its these bearings that cause the noise so common to the NP200. They are tapered brgs. just like in a differential. an like in a diff. if they arent set up right they will sing. You will need an old fashioned bar type torque wrench to measure that preload (it will be in inch lbs -as given in tm) another opt is a torquemeter (a torque wrench w a dial indicator in the handle) they r very expensive, best if you can borrow or rent that type, a click type or electronic type wont work for measuring a preload. If you set it up right it will make for a much quieter case.

Charles are Those #’s are they for the shaft seals? If so what’s the #’s for the small seals for the hi/lo and 2/4 selectors?

oh i go back and re read and see you cant remember them lol if you can pm me the#'s on Monday that would be great! thanks a bunch

MSeriesRebuild wrote:If you plan to use NOS seals, don't bother doing anything, it will be all the same difference as NOS seals are worthless. Most likely you have rust pitting on the shift shafts and all 4 companion flange seal surfaces. Installing the very best new seals will not stop the leaking if it mates with a pitted surface. Never been any water in the case; don't fool yourself, you are talking about a 60 year old case that was once in military service, to think no water has ever been in that case is a myth. It really is not a big deal to remove the 2 rear drive units from the case to inspect it, most likely a fair portion of the leaking is coming from gaskets as well as oil seals. If rust pitting is present as it is in 99.9% of these cases, a rebuild is the only way to address the issue and get a good result.

I'm not casting a vote in your poll. Now that you have enough hard facts to base a wise decision on, you can approach it however you see fit.

The seal # is National 410308, redi-sleeve # is 99212, the shift shaft seal # escapes me at the moment, I can post it on Monday if you need it. All are available locally, no need to order in and pay freight.

The shift shaft seal # is National 470954