Transfer case slips out of gear..

[Jason Mills]

I am appreciating both opinions. I know I have a limited amount of true experience.. so other opinions help me to understand what I may be slightly aware of but not fully conscious of .

Today I had some time to think while driving, and came up with the reason I was spinning the bearings dry. It has to do with my belief that such a procedure is necessary to check used bearings for 'roughness' once they have been cleaned, to determine if they are ok for re-use.

so that was what I was doing spinning dry bearings which happened to be new. What I was unable to express, until reading both of your posts is that there was/is a place in the rotation of the bearing that is both a sharp noise as well as sharp or pulse like feeling. now that I am wring it, it seems kinda silly, but I was unsure before.. my mind was saying " It's brand new".. as well as "this seems different than the other one"

I am not sure how to take a cage off the bearings, is it possible to do that with out ruining anything? anyway, I will be ordering a new bearing, and if I spend $30 foolishly, that is better in my mind than skimping, and causing a problem because of it.

[Frank Irons]

Jason,

No you can't remove the cage, well you can, but don't do it. When you establish the preload on your idler shaft assembly it should be obvious that the bearings are performing smoothly. If the assembly feels rough you have a problem do to bearing quality (which I have never experienced) or assembly procedures. Are you using a service manual for your rebuild? I wish I could be there while you are doing this, describing procedures and advice on the internet is difficult. But as Charles suggests, while everything apart is the time to make sure things are right

[Jason Mills]

Jason,

No you can't remove the cage, well you can, but don't do it. When you establish the preload on your idler shaft assembly it should be obvious that the bearings are performing smoothly.

I have spent 20-30 minutes adjusting the number of shims to get a smooth, yet end-play free set up on the idler bearings. It was in doing this that I discovered that the idler gear would kind of make a 'ringing' sound even when there was no preload involved.. so I took the top bearing out and spun the gear on the shaft with just the lower bearing and race.. and it did make the typical noise but with out the rough sound.

I then used an old bearing in place of the noisy one and as I remember it, it still made noise.. so I assumed it was the race. In putting a new race in, I have now come to decide the new bearing makes the clacking noise.. Now with the new race, it runs smooth with the old bearing, and noisy with the new one... all with out any pre-load shims or spacer, or nut on the idler gear shaft.

It seemed to me that .055 worth of shims was too loose. about .050 was about right, and .046 was too tight. I wanted a greater selection of shims, than what came in the rebuild kit and so asked the seller if more shims were necessary, and he replied that it was uncommon to need more than what was in the kit, when rebuilding the NP 200.

Yes I am using the service manual, as well as the military manual for the M37. I am enjoying this learning process. it is at time frustrating, but overall it is much more enjoyable than frustrating. Also I do hope and intend to get it right, even if it takes an extra month to finish the job. I don't seem to be in a hurry, so that is likely good for a positive outcome.

I am sorry to be taking so much time on this particular subject. It seems that I am more able to write and describe what I was seeing/experiencing now than I was aware of when I first started asking questions about this race/bearing issue. I am grateful to you both Frank, and Charles for your willingness to bear with my learning curve, and blundering attempts at being descriptive.

Jason

[Gordon Maney]

I have spent 20-30 minutes adjusting the number of shims to get a smooth, yet end-play free set up on the idler bearings. It was in doing this that I discovered that the idler gear would kind of make a 'ringing' sound even when there was no preload involved.. so I took the top bearing out and spun the gear on the shaft with just the lower bearing and race.. and it did make the typical noise but with out the rough sound.

I then used an old bearing in place of the noisy one and as I remember it, it still made noise.. so I assumed it was the race. In putting a new race in, I have now come to decide the new bearing makes the clacking noise.. Now with the new race, it runs smooth with the old bearing, and noisy with the new one... all with out any pre-load shims or spacer, or nut on the idler gear shaft.

It seemed to me that .055 worth of shims was too loose. about .050 was about right, and .046 was too tight. I wanted a greater selection of shims, than what came in the rebuild kit and so asked the seller if more shims were necessary, and he replied that it was uncommon to need more than what was in the kit, when rebuilding the NP 200.

Yes I am using the service manual, as well as the military manual for the M37. I am enjoying this learning process. it is at time frustrating, but overall it is much more enjoyable than frustrating. Also I do hope and intend to get it right, even if it takes an extra month to finish the job. I don't seem to be in a hurry, so that is likely good for a positive outcome.

I am sorry to be taking so much time on this particular subject. It seems that I am more able to write and describe what I was seeing/experiencing now than I was aware of when I first started asking questions about this race/bearing issue. I am grateful to you both Frank, and Charles for your willingness to bear with my learning curve, and blundering attempts at being descriptive.

Jason

Stop apologizing.... there is no call for it.

[Charles Talbert]

Shim pack

When you are seeking a free rolling, no end play set up, many times the furnished shims are not sufficient for getting the set up JUST right. We have our own shim punch that we had custom built several years back because of this. We keep shim stock of various thicknesses on hand so we can simply punch our own as needed, saves much frustration and enables us to get the set up just right.

Do you have the special tooling necessary to do this set up with the idler gear/shaft assembly outside of the case? This makes precision much easier and faster.

[Jason Mills]

When you are seeking a free rolling, no end play set up, many times the furnished shims are not sufficient for getting the set up JUST right. We have our own shim punch that we had custom built several years back because of this. We keep shim stock of various thicknesses on hand so we can simply punch our own as needed, saves much frustration and enables us to get the set up just right.

Do you have the special tooling necessary to do this set up with the idler gear/shaft assembly outside of the case? This makes precision much easier and faster.

I am quite sure I do not. Presently I have been adjusting the idler gear/shaft preload with idler shaft being held by a vice vertically, and the idler gear and bearing adjustments being made by trial and error. As I am writing this I am wondering if you have made something that allows you to measure the distance between bearings and then figure out the necessary shim thickness via math, rather than through my method...

what is the range of variance that is sometimes found as you set these components up? The factory service manual suggested .030 as a starting point. I went up to .055 to find play in the bearings, and then started removing shims. It will probably change when I put the next bearing in, I would assume. Also I need to measure all my shims, but I know most of them are .015 in thickness.

[Frank Irons]

Jason,

This is the tool you need to adjust your bearings. The tool simulates the transfer case wall when you tighten the idler shaft nut to 150 ft. lbs. The long handle is needed to hold the shaft still while tightening the nut. This allows you to work on the idler outside the case, which much easier as Charles stated. You didn't mention torquing the nut on the shaft in the vise and this must be done. Without a spacer tool like this it would be impossible to this in the vise. I usually start with a thick shim pack, assemble the bearings, torque the nut and measure how much movement I have with a dial indicator. This will give you starting point for removing the right amount of shims. Remove some shim and reassemble, retorque, measure until you get the fit and feel you want. If you have access to a surface grinder you can grind your thick shims down in .0001 increments. It also helps, as Charles stated, to have some thin shims in your initial stack up; a .003, .004, and a couple of .005 work well.

Frank

[Desoto61]

The spacer isn't hard to replicate, as Frank stated it's basically just a spacer so you can simulate the unit being installed in the case. I just had a piece of pipe big enough to fit over the idler shaft cut to roughly the thickness of the case.

I was fine without the bar attached but you could weld one on easily. Like Frank said, this one is probably more important than the idler install tool since getting this set up correctly is very important, but both make the job easier.

[Gordon Maney]

The spacer isn't hard to replicate, as Frank stated it's basically just a spacer so you can simulate the unit being installed in the case. I just had a piece of pipe big enough to fit over the idler shaft cut to roughly the thickness of the case.

I was fine without the bar attached but you could weld one on easily. Like Frank said, this one is probably more important than the idler install tool since getting this set up correctly is very important, but both make the job easier.

Nice photo!

[Charles Talbert]

Simulating case thickness and torqueing the nut is imperative, once you have the shim pack correct, then you must have the correct installation tool to get the shaft back through the shim pack as it passes through the bearings, spacer, and shims going into the case. Otherwise you will never get it through the shims without losing and destroying some in the process. We made ours so it threads onto the shaft stub and fits tight up against the shaft leaving no crack for the shims to fall into, makes the job easy.

The standard shim thicknesses are.015", .0125", .005", and .004". We cut some also from .001", makes a just right adjustment way easier.

[Desoto61]

Nice photo!

Thanks, I documented the heck out of that build both for my information and to help others. That photo and just about every other one I took during my rebuild are here for reference.

I did have the re-installation tool, someone loaned me their home made version, though it didn't work as well as advertised, but that might have just been due to that specific version.

I did find one available from a web site somewhere for the NP205. Someone purchased one but I think had issues making it work with the NP200.

[Jason Mills]

The spacer isn't hard to replicate, as Frank stated it's basically just a spacer so you can simulate the unit being installed in the case. I just had a piece of pipe big enough to fit over the idler shaft cut to roughly the thickness of the case.

I was fine without the bar attached but you could weld one on easily. Like Frank said, this one is probably more important than the idler install tool since getting this set up correctly is very important, but both make the job easier.

I'm a little bit deflated here. Concerned that this rebuild may turn out to be over my head..

I have been working under the assumption/hope that an old bearing can be used as a spacer to check for bearing adjustment. With that being said, I have to ask why is torquing the nut to 150 Lb-FT. imperative to checking the idler shaft bearing shim? The shims are not of the crush type.. so is there a difference between 50 Lb-Ft and 150, from the perspective of bearing adjustment?

so my less experienced mind says once the play is gone, and the bearings roll freely, the adjustment is as it should be. I do not mean to be implying that I am disagreeing or being disrespectful. I guess I am asking to understand the why behind the need.

in any case, My new plan is to take apart the old "spacer" bearing and weld a bar to the inner cone. Does that sound like it would work?

[Charles Talbert]

I'm a little bit deflated here. Concerned that this rebuild may turn out to be over my head..

I have been working under the assumption/hope that an old bearing can be used as a spacer to check for bearing adjustment. With that being said, I have to ask why is torquing the nut to 150 Lb-FT. imperative to checking the idler shaft bearing shim? The shims are not of the crush type.. so is there a difference between 50 Lb-Ft and 150, from the perspective of bearing adjustment?

so my less experienced mind says once the play is gone, and the bearings roll freely, the adjustment is as it should be. I do not mean to be implying that I am disagreeing or being disrespectful. I guess I am asking to understand the why behind the need.

in any case, My new plan is to take apart the old "spacer" bearing and weld a bar to the inner cone. Does that sound like it would work?

You need more knowledge it seems. The set up spacer must be the exact thickness of the case or your set up done outside the case is worthless. You MUST torque the assembly to get the set up correct, assuming a set up with the assembly loose is also worthless. It is when the proper torque is present that the free rolling, no end play must be checked. If you achieve that set up with the shaft nut loose like you were saying, when you install the assembly in the case and torque the nut, the assembly will be off the charts out of spec.

Really doesn't matter whether you disagree, the fact is your thinking and assumptions are for sure taking you down the wrong road. You have not mentioned it, but the 2 gear drive units must be set up to similar specs, also using shims, but these bearings have a definite preload and are not free rolling. You will get a disasterous result quickly if these specs are not set up correctly.

This is about all I know to say. I'm assuming since you are into this that your desire is to finish it yourself. We offer rebuild service if you need help, you can contact us via the contact us link on the website below.

[Frank Irons]

Jason,

You will be torquing the idler shaft nut to 140 to 160 ft lbs when it is in the case, that is why you need to do it in your setup. Do an experiment, tighten the nut to 50 ft lbs and set up your shim pack. After you get bearings all set up and are satisfied with the feel and clearance tighten the nut to 150 ft lbs and see if anything changes.

Frank

[Jason Mills]

Jason,

You will be torquing the idler shaft nut to 140 to 160 ft lbs when it is in the case, that is why you need to do it in your setup. Do an experiment, tighten the nut to 50 ft lbs and set up your shim pack. After you get bearings all set up and are satisfied with the feel and clearance tighten the nut to 150 ft lbs and see if anything changes.

Frank

Great suggestion, then I can learn first hand.