transfer case question

[Cav Trooper]

Frank,

Thanks, I thought as much for the races on the shaft and gear. The pitted race question was more rhetorical since I knew the answer but was hoping for a magic solution, something other than just throwing green paper at them..

CT

[Frank Irons]

CT,

I forgot to add that even if the surfaces are smooth there are wear limits for the surfaces involved. TM 8030 is a good reference for sizes and wear limits on these parts.

Frank

[Charles Talbert]

Just looked this up a couple of days ago for someone

The bearing surface diameter on a new input shaft where the needle rollers go should measure, 1.6161" - 1.6164". The wear limit for this area is, 1.6152". If it is smaller, either replace it, or have it professionally built up and ground back to standard specs.

The 2-speed gear bore in a new gear, 1.9331" - 1.9336". Wear limit for this area is, 1.9346".

[Kaiser2boy]

Well, another fine mess!! I decided to pull the transfer case since the park brake looked pretty gunked up and I wanted to replace that seal and clean up the whole case. I pulled the frond shaft seals and replaced them. I need new flanges as I suspected. Then, since I got ahead of myself by just doing the fronts without disassembling and inspecting the rest, I pulled the park brake assembly and the tapered bearing are pitted. I then pulled the whole shaft assembly and the straight needle/roller bearings races are pitted, not bad but how much can be acceptable? Now, I'm in for replacing all the bearings!!!!!!! Well, no one said these were cheap projects. First the tranny, then the brake master cylinder (that part is still not right, too much pedaly free play) then, exhaust, then, the brake and clutch pedal assy bushings, then, the broken door glass from previous owner incorrect installation, then, rear differential pinion seal, new bushings in the steering box and pitman arm. The list goes on. Good thing I'm retired and have the time to work on her, bad thing I'm retired and may have to find a job to pay for the repairs. My wife keeps asking why I need to do this since it was restored when I bought in and I assured her it needed nothing, that was a grand or so ago. She keeps looking at the charge card bill and frowning. I drove these in Germany and Viet Nam and never had to wrench on them, just hop in and drive. Now I wrench and really have gained a repect for the guys whole kept them running back then. I know they were newer but, it looks like they still had to keep up the PM. All in all, I'm having a great time solving problems and getting her ready for the Dayton convention which is only about 30 miles from me. I'm insterested in thoughts on the straight roller bearings, do I have to buy the gear and shaft for for the races or can I buy just the races and bearings?
Well enough, rant, ramble, back to cleaning and wrenching.

How much free play is there between the MC and the push rod? There should be about 3/16ths .
Does your truck have the dust boots on the top of the brake pedal shaft? Too much gap at the MC can cause excess free play and missing rubbers can also make for a longer travel of the brake pedal. Not much but it all adds up. I went through a few monthes of torment with my brakes getting them right . In my case the "new" Tiwan MC was not put together right. But before I hit on the answere I had gone over the brakes again and again and again looking for why they would not work right.

[Cheyenne Dave]

The bearing surface diameter on a new input shaft where the needle rollers go should measure, 1.6161" - 1.6164". The wear limit for this area is, 1.6152". If it is smaller, either replace it, or have it professionally built up and ground back to standard specs.

The 2-speed gear bore in a new gear, 1.9331" - 1.9336". Wear limit for this area is, 1.9346".

That was me Charles, and thanks. Our input shaft turned out to be within spec.

C.D.

[Charles Talbert]

That was me Charles, and thanks. Our input shaft turned out to be within spec.

C.D.

OK; pits that are simply the product of normal wear most times are not the end of the line. Pits that are the result of rust, (water in the case) most often don't have such a happy ending. If you see some minor pitting that is not rust related; seldom is that shaft worn outside of normal wear specs. It's when you see actual flaking off of the hard surface area taking place; that is cause for great concern.

[Kaiser2boy]

Well, like usual nobody has mentioned the one thing that is the more likely cause of seal leakage than the seals themselves. That is grooving or rust pitting on the yoke seal mating surface. Put all the new seals you want on a grooved or pitted yoke sealing surface, and the dripping will keep right on coming. A new seal will not work if mated to a rough surface. Do not use an NOS oil seal; you will hate yourself in the morning as they are no good a will leak no matter what. The best seals we have found are National #410308, used in combination with a National #99212 Redi-Sleeve pressed onto the yoke surface to provide a new surface for the seal lip to mate against. If all is installed correctly, this is as fool proof as it gets in doing a good, no drip, sealing job.

If we are doing a seal replacement only job on a T/case; it is done without removing the case usually. We give the case and surrounding area a good steam jenny bath and go for it. We have good seal pullers that work well generally, however we do find stubborn ones that require a little something extra at times which we just deal with however we can. We use anaerobic sealer on the retainer seal bores, then tap the new seals in using a 3"X5" piece of 3/4" flat bar and a hammer. Using the flat bar makes it easy to press the whole seal squarely and completely flush to the edge of the retainer. Unless there is some extremely unusual circumstance in play, this is easier than pulling the case. That is especially true if you don't have proper equipment to support and handle the case well. It is very top and back side heavy and can easily topple off a jack that does not have the means for bracing and supporting the whole case in a steady state. Trying to use a jack that does not offer means of supporting the case so there is no chance of over balance is not a smart thing to do. This case is not well balanced at all and must have solid support; otherwise your chances of it getting away from you may be greater than you think.

It was mentioned about the gasket/shims for the front bearing retainers. If you do remove the retainers from the case, be sure you clean off old gasket well, measure and use the correct shim pack thickness upon reassembly. The actual pack thickness should be approx .006" thicker than the measurement to allow for compression. Remember the retainers are cast, if a too thin shim pack is used; it will result in the ears on the retainers being broken off when the nuts are tightened.

Hi Charles, is that National seal# 410308 OK to use if the yoke surface is good and does not need a sleeve ?

[Charles Talbert]

Sure; but it is precious few that don't have some issue going on that needs a sleeve; so check it well.

[Kaiser2boy]

Sure; but it is precious few that don't have some issue going on that needs a sleeve; so check it well.

Will do.
The sad part is that it was NOT leaking hardly at all, a few drops after a nice run. Then I cleaned off all the mud dauber build up and mouse nest and now it leakes too much to ignore.
I may have damaged the seal with the pressure washer and wire brush. Maybe the crud was acting as a blood clot.

[Kaiser2boy]

Got the yoke off and the bearing retainer with no problem. After it was cleaned I could see a slight indent where the old seal had worn in.
The old seal is a monstrosity. It is about 3/4 of an inch thick. The new seal is about half that thick. The shaft on the yoke had no pitting at all and was nice and smooth.
I looked at where the new seal would sit in the retainer as comparied to the old one and the seal lip hits very clost to the indentation from the old seal.
Howevr that is if I pressed the seal fully in to the retainer. I did just that, I pressed it fully in and then pressed another seal right on top of it. It did not go all the way in but most of it pressed in and the seal lip on the second seal hits on nice smooth shaft. I reassembled everything and took it for a 10 or 12 mile run. No leaks.
OK now you can scold me for being a Gypsy. I figured it was not a real hard job and if it works great , if not I will worry about it then. So far so good.

[Gordon Maney]

A conventional oil seal is designed to leak enough to lubricate itself. If the seal could truly run dry, stopping all oil, it could not survive.

If, by chance, the inner seal stops too much of the oil on its own, your outer seal may not be able to survive as long as you want.

[Charles Talbert]

Got the yoke off and the bearing retainer with no problem. After it was cleaned I could see a slight indent where the old seal had worn in.
The old seal is a monstrosity. It is about 3/4 of an inch thick. The new seal is about half that thick. The shaft on the yoke had no pitting at all and was nice and smooth.
I looked at where the new seal would sit in the retainer as comparied to the old one and the seal lip hits very clost to the indentation from the old seal.
Howevr that is if I pressed the seal fully in to the retainer. I did just that, I pressed it fully in and then pressed another seal right on top of it. It did not go all the way in but most of it pressed in and the seal lip on the second seal hits on nice smooth shaft. I reassembled everything and took it for a 10 or 12 mile run. No leaks.
OK now you can scolled me for being a Gypsy. I figured it was not a real hard job and if it works great , if not I will worry about it then. So far so good.

I'm sure not going to scold you; but I will tell you that you wasted the money on the 2nd seal, and it may well be the ruin of your job. Let me explain; any oil seal has to have some lubricant to last. If the inner seal you pressed in first does the job, the outer seal will get no lube, build up heat, and as a result will be ruined in a short time span. This will allow debris and water to find its way past the outer seal which will of course become trapped in between the inner and outer seals. Likelyhood of that trapped debris ruining the new inner seal is quite high. I've seen this issue more than once.

As long as the yoke mating surface is good, 1 seal would have done the job better than 2. Seal technology has changed and the thick original seals with that outer felt strip is 99% of the reason most yokes get ruined with rust pits as the felt stays wet causing severe yoke rusting. That is just one more reason NOS type seals are no good. The new seal can be pressed to any depth in the bore to get the seal lip on a good area, and will function just great all by itself.

[Kaiser2boy]

Or maybe the inner seal will leak a bit and let just enough oil pass to lube the outter one.
It is just an experiment.
I was surprised at how simple it was to remove the yoke and retainer. I will keep an eye on it and if it starts leaking I will re do it.
I did apply grease to the shaft and seals prior to sliding it on so there is some lube between the two seals to start with.
Worst case is that in time the outter one will fail and then the inner one some time later and it will start to leak again.
I thought also that the outter one would protect the inner one to some degree like the original one with the felt wiper.
But for right now its staying in there.

[Charles Talbert]

Is the whole lot of M/C's bad?

How much free play is there between the MC and the push rod? There should be about 3/16ths .
Does your truck have the dust boots on the top of the brake pedal shaft? Too much gap at the MC can cause excess free play and missing rubbers can also make for a longer travel of the brake pedal. Not much but it all adds up. I went through a few monthes of torment with my brakes getting them right . In my case the "new" Tiwan MC was not put together right. But before I hit on the answere I had gone over the brakes again and again and again looking for why they would not work right.

Have a truck in the shop right now that came in last week with brake issues. Investigation turned up a new fresh from Taiwan M/C on it, installed by the owner that is displaying the exact same issue you were having with yours a while back. This wrong assembly of these units that I've heard several people speak about is undoubtedly common to the whole lot.

What I am scratching my head over is why the seller keeps pumping out these wrongly assembled M/C's to their customers. I'm sure more than 1 person has called them experiencing issues as I recall you saying that you called them back. I'm glad I don't have a bad batch on the shelf, (our new ones are from a different source) but if I did; I would stop marketing them until I could go through them and correctly assemble. Just to keep on pushing components that you know are bad must have a negative effect with buyers at some point; doesn't it??

[gusbratz]

I agree Charles. I don't understand some people. Must be they are more interested in making money than doing their job right. I just don't understand how they could be that short sighted. Every time they do wrong by a customer they not only lose his business for life but make an enemy out of him and he will tell all the people he knows not to buy from that guy. Maybe that seller only has a few m37 parts and he figures if he can get them sold then cares. He will just get out of dodge so to speak. (That was a good pun by accident) and move on the the Volkswagen crowd or something.