Another (challenging) WH (green) Suburban 3 Pc Transmission Overhaul

[oliver2-44 9,848]

As if I didn't have enough Suburban parts for my 2 project tractors, awhile back this one found my shed and decided to stay. 

It has a better hood  and I hopped, "maybe..." a better transmission that the first one I overhauled with the noisy pitted gears.

But I knew going in that the transmission would roll about 1/2 rotation and thenone or both rear wheels would lock up.  It has had at least one brush coat of red pant, then the "Greennnnn" paint

 

So its hot outside and  I have a nice AC in my shop, good time to work on a lot of things, why not another transmission.

The solid pan seat and a transmission casting number of  M21-9 indicate this is possible an early Suburban

I polished the rusted dash plate to get Serial number 27632

 

I disassembled the transmission backwards because I didn't have a thin enough wrench to get behind and unlock this unusual drive pulley to get it off.

Once I had just the side plate I took it to my old country mechanic friend, and of course he had a large thin homemade flame cut wrench hanging on a nail just waiting. 

. 

It had the normal watery chocolate oil, not good, but not too bad.

Now we get to the meat of the original problem and my current dry assembly problem. The Differential

As I said the tractor would roll about 1/2 rotation and the rear wheels would lock up.

Someone has been in here before, as this transmission case with M21-9 (late 1959)  originally would have has a one piece differential and this has a 2 piece where the gear bolts onto the hub.

Also, (I didn't take a pic) but the axles have been flipped and the ends redrilled to put the spur gears on the other end and allow a new section of axle to ride in the axle bushing.

 

Yep, here was the problem, one of the diff bolt nuts came loose and was locked up in the diff spur gears. The nut was very chewed up and part of the bolt was nowhere to be found, ground up I guess.

Besides the one broken bolt the other 3 bolts had also loosened some.  I suspect they drove this thing a while with it making noise!

As part of the chewing, the diff gear wore into the side plate ...just a little.  (you can see the metal shiny spots where I ran a flat file over the side plate to smooth it.

(Also the file marks on the end of that axle tube are by me cleaning it up a little.

But amazingly the gears had a few nicks, but no real damage a file couldn't clean up.

 

Now on to the reassembly challenge! 

(This is where I use my lifeline and call @stevasaurus, @Racinbob, @pfrederi @Achto  @WHX??  and all other 3 piece transmission guru's)

I've installed all new bearings in the side plates and bushings in the axle hub and axle shaft bushings.

I'm been doing a test assembly, honing the axle bushings so the axle is just a little loose in just the bushing and side plate, but snug but free enough to rotate when the diff and side plates are assembled to the case.

Three honing/test assembly cycles and the axles shafts turn nicely but not loose when assembled in the 3 piece case.

BUT

The differential gear is rubbing on the cast case on the back lower bottom side. When the diff is rotated the gear drags intermittently, sometimes tight in the 6-9 oclock part of the casing.  

In that area you can see where I had taken an emery wheel to gouges in the casing where the diff gear had contacted it when the bolts were loose. 

 

(pic below) Here's the upper side of the casing and you can see the diff gear has about 1/16 - maybe 3/32 clearance ( I could not get a 1/8 welding rod in there. )

There's not much room in this casing!

 

I've had the diff and side plates assembled and apart several times checking things.

Here with the right side plate bolted on ( no gasket)  (input shaft side down)  I verified the diff hub had clearance and would not hit/bind when the left side plate was put on.  

 

Notice the 1/8"+ clearance (under the right end of the ruler)  indicating the right side plate is "sprung" a little

See the screw driver showing the left side plate is sprung a little as well.  It would seem that when I bolt this front down it would be pulling the diff "away" from the fear of the diff where its dragging!

You can not press the plate down easily with one finger, but you can push it down with the palm of you hand with a little effort.

Checking the squareness of the right side plate stub that the differential bushing rides on. Its off a tiny bit, but not a lot considering how these side plates flex with the pipe axles hanging out there.

Checking the squareness of the left side plate stub that the differential bushing rides on. Its also off a tiny bit, but in the opposite direction when compared to the other side.

 

So this is where I'm at. 

Are the sprung side plates and the slightly off diff hubs kicking the diff gear into the casing ?

 

One other though I've had,.... with the PO redrilling the axles, could the two ends in the diff be hitting each other, kicking the gear into the casing? (I've hesitated to drive the roll pins out of diff pinions to get in there to see this) . 

But when the diff is out of the case and just one axle in a side plate you can grasp the upper axle and turn it nice and freely and wiggle side in all directions a little. But I cant move the axle up/down  (in/out) of the diff but maybe a tiny bit?

 

Dino, you recently make the comment that a WH a Sunstrand transmission wasn't a Corvette, and these 3 piece transmissions are crude compared to that.  What am I missing!

  

All I wanted was a nice simple 3 piece transmission rebuild to use in place of the pitted noisy one. 

I started a few weeks ago with a nice clean organized work are.  Now I've had this thing apart enough times that everything is a mess and my gray hair is a little whiter!!

Before final assembly I will start over and give everything another paint thinner bath and a nice clean towel work reassembly area 

 

So @DeepH2O While I might have been helping you with some transmission questions,  I get stumped too.

 

 

Edited July 2, 2022 by oliver2-44

[stevasaurus 22,857]

Jim, I think this is going to take a few of us to figure this out.  I'll start...somebody has been in there before.  Your differential shows that by having the bolted on bull gear...that is also a different differential housing to go with that bull gear..  One of the things I have found in these 3 piece trannys. is the axle tubes are not necessarily plumb on those side plates.  Do you have the means to take those axle tubes and plumb them up??  Grind the tube out of there and re-weld them square??  With what you have told us...that is what I think needs to happen.  Like you are showing, it does not take much.    @Racinbob  I'd like to see what Bob thinks.  

[oliver2-44 9,848]

In some ways those diff hub tubes are out such a little bit wonder if i could get them much squarer with any welding deflection. But I agree it, with the small clearances in that case it doesn't take much to  throw things off.

I had checked the longer outer axle tubes and they didn't seem off much, but with the weld it the way it's hard to really get a square on them.  i'm going to try to come up with a better way to check them. maybe use a piece of tool steel as a spacer over the welds, then at the ends also.  

[Racinbob 11,205]

Personally I don't see anything out of the ordinary. Virtually every 3 piece transmission I've had apart I see evidence where the gears have battled the case at some point. Seeing where the diff gear has ground on the rear of the case is common. Unless it's hitting the case now I wouldn't worry about it. I don't think it's possible for something to deflect the diff into the case once it's assembled. A very common problem is what Steve is referring to. The axle tubed aren't aligned perfectly straight. Referring to the 400 I rebuilt. I had put all new bearings and bushings in it. Thanks to Steve the axles were new. I could put it together with the case bolts loose and things were as smooth as a babys butt. Once I snugged things up nothing would turn. After opening it back up at least a gazillion times trying to determine what was binding I finally settled on the axle tubes were just a fuzz off parallel. I picked up a piece of 1" round stock long enough to go completely through both tubes and assembled things with that in place of the diff and axles. Side plates loose, turns freely. Side plates tight, won't turn. This totally eliminated the possibility of is being anything else. I wouldn't try to reweld things. You might be able to gently persuade them straighter but that could also end up with a disaster. I simple honed the bushings (brake cylinder hone) until I freed it up. It doesn't take much. It's been several years now and things are still fine. I'd suggest on the final assembly that you use thread sealant on the case bolts. That iron just doesn't seal well. 

[oliver2-44 9,848]

Well I had a little shop time last night. As much as I didn't want to my gut told me I need to drive those roll pins out of the differential and disassemble it.  Thankfully it all looked good. I'll get some pictures today. 

Then I worked on a better way to check the axle tubes and inside stubs for the differential. I held a piece of tool steel against the axle tube just above the belt and a piece of tool steel at the top of the axle tube. Then held an aluminum speed square against which ever piece of tool steel it hit first.  With this method I need a third or fourth hand to use some feeler gages to measure the gap between the speed square and tune.  My wife will be around today and I will try to induct/enlist her in her first transmission work. Pictures later today.  

[oliver2-44 9,848]

This is my setup. I bolted the side covers in place and used tool steel to bridge over bearings to get a better square reading on the axle tubes. 

This is the right side cover. The end of the axle tube is bent 0.025 forward and 0.030/0.035 this down. I double check the direction as I would have thought it would be bent the opposite directions. 

This is the left-input shaft cover. The end of the axle tube is bent 0.044 this to the rest and 0.025 the up. This is the direction I would expect them to bend from normal hard use. 

 

Im going to the farm next week and plan to pick up a piece of short heavy channel iron. I think I can use pipe clamps to straighten the axle tubes a little.  But not sure the axle tubes are causing my problem. 

I could only check the differential tubes on the inside of the case in one direction. Both were square in the front to back direction. 

I set the differential in place. Just pushing straight forward I measured 0.007 which would be the clearance between the diff bushing and the side plate diff tube

This 0.007 in the right direction would be enough for the diff to clear. 

 

However I could rock the diff 0.042 . All of the checking is with the diff on its side, not flat in its normal direction. 

Im thinking of putting both side plates on with just the diff/no axles. Have a small rope wrapped several times around the diff (like a recoil starter). And bring the rope out the shifter tube. Give it a pull and see if the diff hits in the normal operating direction

  Any other suggestions are welcome. @stevasaurus @Racinbob


 

[stevasaurus 22,857]

I think usually, it is a bad bearing under the large part of the mushroom gear that causes the contact with the case and bull gear.  It is also possible that bad outer bushings, or inner bushings could cause the contact.  Having a new bearing in there should fix that...if that was the issue.  New axle bushings should help also.

    I have a couple of other ideas you might try before trying to bend those axles.  1.  The wall of the casing is about 1/4".  You might try grinding where the problem is a little bit...giving it more room.  2.  That bull gear is the same on both sides.  Turn it over, or rotate it 90 to 180 degrees, and see if that helps.  3.  Grind a touch off the end of the bull gear points where it is close.  The gear will still work with the mushroom gear...thinking it is just a very little bit.  @Racinbob  What do you think??

[Racinbob 11,205]

I hate to be a spoiler here but, again, what I'd do is hone the axle bushings until the axles will turn, put her back together and let it settle in by using it. If you remember from our conversations Steve, I searched for weeks trying to find something to blame for the binding. Once I decided that it was definitely the axle tubes I thought about trying to tweak them but chickened out. It was just too risky. They were like that for 60 some years and spun fine before I took it apart so they should after I put it back together. The axle tube not being square to the side plate is not as important as the axles tubes being lined up with each other. There's other things that can cause the misalignment in the two side plates such as a little slop in the mounting holes, the cast case, etc. Let's face it, these transmissions are, for lack of a better word, crude. But they are also tough. If there is nothing obviously rubbing or a bearing not seated properly I would hone the axle bushing so the axle will turn and let the Wheel Horse Gods do the rest. It may have been frustration but that's what I finally did. The axles were tighter than I liked at first but now they are just right. I think the axles seated themselves in the bushing where they wanted to be ignoring the multitude of other inaccuracies trying to throw them into a bind. Don't get me wrong. I love the ingenious work here but I've been there, done that. But I think it finally came down to throw it back together and use it or toss in in the Kankakee River. 

[Lane Ranger 10,992]

You really can’t do too much honing on the new axle or differential bronze bushings for your axles to turn smoothly.   I have a rebuilt transmission on an rj I am redoing for my brother that turns fine in the case and on the tractor when lifted on Jack stands .  But it is tight when lowered to the ground.   I am not going to take back apart and redone.  
 

 

My answer is put it back on Jack stands and run the motor in first gear so the transmission can wear it’s own way try the bronze bearings.  I did not do a lot of checking on squareness for the axle tubes on the side plates but they look pretty good.   
 

I may have a good suburban brake side plate Oliver 2-44.   You could have for Twenty plus shipping.  I am out east right now but will take some pics when I get home.  I still have about four containers of rj/suburban three piece transmission parts!

 

 

I did but a non-numbered three piece rj transmission that was rebuilt while I was at the Big Wheel Horse Collectors Club Show in Gettysburg two weeks ago .  I have already repainted it.  Might have to use on another rj I have for redo! 

[oliver2-44 9,848]

@Racinbob I’ve honed the axles and with just the diff in the case it turn nicely but the diff gear drags on the case. It’s almost like I need to drill the holes in the right side plate 1/32 maybe even just 1/64th larger to slide that side forward to give the diff gear clearance. 
I will probable grind the case a little as Steve has suggested. But I want to try my rope winding test first. I’m really thinking on this transmission the bent axle tubes have nothing to do with the diff hitting the case

[Racinbob 11,205]

3 hours ago, oliver2-44 said:

@Racinbob I’ve honed the axles and with just the diff in the case it turn nicely but the diff gear drags on the case. It’s almost like I need to drill the holes in the right side plate 1/32 maybe even just 1/64th larger to slide that side forward to give the diff gear clearance. 
I will probable grind the case a little as Steve has suggested. But I want to try my rope winding test first. I’m really thinking on this transmission the bent axle tubes have nothing to do with the diff hitting the case

 

Ohhhhh! Dummy me. I must have missed something here because I didn't realize it was still dragging the case. I thought it only had the marks at the back of the case and your issue was axle binding. My first thought was to do as Steve mentioned. I'll go back through this thread again and see if I can come up with more. 

[stevasaurus 22,857]

The thing I am wondering, that differential is not stock, it was changed from the old one.  There is a reason it was changed.  I suspect the damage to the case was done with the old differential.  I do not see any damage to the bull gear on this differential.  Unless Jim sees some scraping on the new bull gear, the pictures do not show it.  Curious.  

   Bob, glad you figured out what we were talking about.    Still want to hear what you have to say.  

[oliver2-44 9,848]

The current differential does not have any scrape marks which I’ve also wondered about.  Sunday evening I did some checking of how much the diff teeth varied and came up with 0.011 max. I wrapped a layer of blue tape around the teeth to help the dial indicator span the gear teeth. There is a section that runs 8 to 11 this high and this is what hits. I’m going to unbolt the gear and rotate it 90,180,270 with the bolt holes and see if I find a sweet spot.  It would be nice if the problem was I didn’t matchmark the diff housing and gear back at disassembly. 

 

I’m helping my Mom for a few days, so hopefully I’ll get back to this mid-week. 

Edited July 12, 2022 by oliver2-44

[Racinbob 11,205]

15 hours ago, stevasaurus said:

The thing I am wondering, that differential is not stock, it was changed from the old one.  There is a reason it was changed.  I suspect the damage to the case was done with the old differential.  I do not see any damage to the bull gear on this differential.  Unless Jim sees some scraping on the new bull gear, the pictures do not show it.  Curious.  

   Bob, glad you figured out what we were talking about.    Still want to hear what you have to say.  

 

I'm at a bit of a loss here. My 400 has scrape marks too but I don't recall seeing anything on the diff gear. Since it wasn't scraping anymore I ended up assuming that, at some point, something broke and a piece got drug up by the diff and scrapped the case. I just can't see any way the state of the axle bushings could cause it. Apparently something broke because it had to be working at some point in the past and caused the problem of it rotating about 1/2 turn either direction. I wish I had a case sitting around that I could play with and try some things. All I can do is keep up with this thread and ponder. Maybe something will hit me. 

[Lane Ranger 10,992]

These two photos make me think you are on to something about the “matching” of the two differential pieces!

 

 

A slight offset would potentially make the gear teeth scrape the center casting housing if impeded by debris , a metal scrape etc.  

[buckrancher 2,694]

its only as good as the guy who dialed the diff. casting in at the factory before machining  it

[stevasaurus 22,857]

One thing, the differential bull gear is the same part as on the 2 piece, 3 speed and 4 speed differentials.  If you have a #5025 laying around, you could swap bull gears.  Jim, don't forget to try turning that bull gear over also.  

[oliver2-44 9,848]

14 hours ago, stevasaurus said:

One thing, the differential bull gear is the same part as on the 2 piece, 3 speed and 4 speed differentials.  If you have a #5025 laying around, you could swap bull gears.  Jim, don't forget to try turning that bull gear over also.  

[oliver2-44 9,848]

 

Well @stevasaurus I rotated the diff gear and snaked that housing over it 4 times with no success.  Then just like you said 

On 7/12/2022 at 5:00 PM, stevasaurus said:

  Jim, don't forget to try turning that bull gear over also.  

.  I flipped the gear and snaked that housing over and  Boom Shaka a Laka it was like there was never a problem    It fit with the tight clearance those things have and rotated nicely.  What was different about it that way I can't tell you, but i was ready to button it up.  So that's what I did. Here it is all together and dressed out. Rotates smoothly and shifts to all gears.  Thanks for every ones suggestions.  @Racinbob Another 5010 3 piece transmission lives on  

 

 

Just for comfort before painting and tractor assembly, I'll run it with my electric motor setup to put a little  time on it 

 

Edited July 17, 2022 by oliver2-44

[stevasaurus 22,857]

I'm glad that something did the trick for that transmission Jim.  That trick has to be remembered.