71 Bronco 14 - differential click / ratchet

[sfjohnson722 26]

Greetings all, first post to this forum.

I am in the process of getting my father's 1971 Bronco 14 (1 0421 6) up and running. After pulling the hydrogear for reworking, I noticed some lash between the rear wheels when on jackstands. I found one of the hubs to be badly worn, but also noticed there seems to be a clicking or ratcheting when turning one side at a time (whether the parking brake is on or off). The opposite wheel does turn in the opposite direction - it just does so with a click / ratchet feel. I was expecting something smoother like with an automobile differential. Is this normal? Should I plan to split the case, and if so what should I be looking for?

Thanks in advance for any information!

Edited October 24, 2017 by sfjohnson722

[stevasaurus 22,872]

Hi, and welcome to Red Square. 

It is going to be really hard to give you good advise with out hearing the click.  Maybe, you could do a short :30 video so we could hear it.  These differentials and the bull gear meshing with the mushroom gear isn't sloppy, but it is not like a car differential.  If you have one of the bearings with some wear going on, that would do it.  If you have any seals leaking, that could be the worn bearing. Since it was your father's, you might have some knowledge as to how good it was taken care of.  If you think it has had good care, I would be inclined to just keep an eye on it and see if it gets louder or worse.  Here is the truth...the only real way to know is to open it up and take a look.  If you can, try pushing it around (not on the blocks) and see if the noise is still there.  Does it click just once per revolution or more?  I would try a bunch of tests before I opened it and also before I decided not to open it.  

[Racinbob 11,234]

Just throwing this out to think about it. I vaguely remember a conversation at a dealer in the 70's. A guy had brought a Raider in because of a clicking in the transmission. The dealer said there was a common problem with the 10 pinion differentials that would cause a clicking noise. It caught my attention because my Dad had a Raider 12 with a 10 pinion. Of course that was a 6 speed but I believe the hydro Bronco has a 10 pinion as well.

[KC9KAS 4,741]

@sfjohnson722  to  and 

[sfjohnson722 26]

My wife insisted I get the video tonight and not keep you all waiting! Thank you for the ideas already.

 

I don't entirely know the history, or at least one that makes complete sense. I don't think that it was too badly abused, except that dad mentioned he pulled some sumac stumps out with it in the 80's (and I would have expected him to ease into the pull and not snapped the chain tight being a heavy equipment operator and semi-driver). He then went on to mow 1.5 acres and blow snow in Buffalo for another 25 years after that with it until 2009. I've never noticed any locking up of the wheels while turning or anything funny like that (the hydrogear does seem to be slow at first in reverse then speed up - hence why I pulled it and it will be delivered to Jim's Tractors tomorrow for an overhaul). Once thing I found odd is that the hydrogear is marked as a Sunstrand 90-2071, not the 90-2046 I had expected as per tractordata. Also there were some remnants of a paper (?) gasket, as well as what I am guessing is black RTV between the hydrogear and transaxle. I asked dad, but he claims the hydrogear was never pulled, and any major work done by a Wheel Horse / Toro dealer that seemed knowledgeable. So while I think it has been used / worked hard, I wouldn't say it was abused too badly. Dad bought this new in '72.

 

When rolling both wheels together forward, or both wheels together backwards, there is just typical gear lash noise - no clicks or any noticeable hang ups. It's only when turning one side or the other that it makes this clicking/ratcheting. Note in this video there is no fluid in the trans axle having just drained it, so I won't work it too much.

 

Here's the video:

IMG_2757.MOV

 

I couldn't tell if the axle seals were leaking since the whole transaxle was covered in ATF from a leaking hose. Looking at the filter screen, there are a few metal shavings but nothing large indicating something obviously grenaded (but again with the RTV gasket and mismatch hydrogear #, I'm wondering if it was pulled and filter screen cleaned at that time).

 

Maybe this is typical; again just was not what I was expecting compared to an automobile diff.

 

@racinbob- I did see on parts tree that the 10 pinon has been replaced with an 11, at least for the 1972 1 0422.

Edited October 25, 2017 by sfjohnson722
moving video to forum rather than external link

[sfjohnson722 26]

The 1st picture is circa 2007 - I'm the masked man in the back doing the dirty work while dad gets the fun job of hauling the brush away. The next two are the start of the restoration shots! It has sat for the last 8 years, and I had to limp it out of the garage and into my trailer. After redoing the battery and starter cables, letting it sit for 48 hours with oil in the cylinder and turning the engine over with a breaker bar, the 'ol Kohler fired up on the 2nd crank with a shot of ether (first crank I forgot to choke and throttle - I was too excited - doh!). The wagon is original, and it has a replacement mowing deck. The original snowblower was sent to scrap unfortunately, but I sourced a 48" long-frame plow this summer which will be better here in PA since it's mostly slush anyway. I am slowly repainting pieces as they come off (I'd removed most of the sheet metal for diagnosis runs around the yard in the 2nd pic). Once things are mostly sorted with the hydro/trans, I'm planning on fresh Firestone bar & tri-rib rubber. I have so many fond memories mowing with this as a kid, and I am probably almost as (maybe more?) excited to get it back to being a workhorse as an adult and hopefully run it another 46 years! (I have a feeling it will outlast me)

Edited October 25, 2017 by sfjohnson722

[meadowfield 2,595]

sounds like it has a 10 pinion limited slip, they can click as the steel ring slips over the teeth.

[stevasaurus 22,872]

That click is not what I expected to hear.  As long as you almost have the trans off the frame anyway, I would open it up and at least change out the seals.  Before you drop the trans...take out those seat bolts and shine a light down one of those holes.  See if you can count how many bolts are holding the differential together.  A 10 pinion Limited Slip differential will have 5 bolts...an 8 pinion differential will have 4.  Here is a video of what a 10 pinion differential looks like inside...

 

 

 

I think someone has been in there before.  You should have the 90-2046, and I have yet to see Wheel Horse use any ATV cement on their gaskets.  Not a big deal...just another reason to open it up and take a look.  Make sure you have the shallow side (input shaft side) down when you open it up.  These trans are not hard to work on...hardly any gears in there...and we can set you up with the numbers for gaskets, seals and bearings (if needed).  I think you will find a copy of the trans manual for Sundstrand Automatics in the "Manual section".  Let us know. 

[sfjohnson722 26]

Well crud... I didn't need another project this weekend, but looking at how hard it was to spin the two shafts in this video, compared to *relative* ease on mine, I agree it's worth digging into it. I see now that perhaps my assumption that minimal shavings on the screen meant minimal internal damage is flawed. It looks like something could have broken inside the differential with minimal metal escaping. Thanks so much for the video @stevasaurus; I will keep you posted once I get a moment to dig in.

Edited October 24, 2017 by sfjohnson722

[stevasaurus 22,872]

I agree with your analysis.  That click just does not sound like it is normal.  Once you take the brake side off, you will be able to pull out the differential without taking any other gears out.  Use the deep side case half as a holder for the differential.  This is important...take pictures for you and us to see.  We can walk you through this. 

You are right about the ease of turning the axle...starting to think you have a broken spring...which means that you may be missing some teeth on either pinions or axle gears or both.  It is funny that you can still turn the axles.  See if you can count the bolts like I said above.  I do not know if you have a 10 pinion differential...I am not familiar with the transmission number that you have either.  Part of why I would like to see many pictures.    it will help others sooner or later.

 

BTW...if you do have the 10 pinion differential...the bolts go in from the top and the nuts would be on the bottom....opposite from what the videos says.  My Mistake on that point. 

[sfjohnson722 26]

I pulled and cracked the transaxle this evening. It was tough to get open, but with a spreader / clamp between the seat bolts and a rubber mallet, it spread open. I mentioned before one of the hubs (the right one) was very sloppy and chewed out at the woodruff key so that is scrap. Turns out the left side was frozen on - penetrating fluid, love taps, and then it snapped in two quite spectacularly using a gear puller. So now two scrap hubs. Once the dust settled and I found myself unscathed I proceeded on. It was a bit tricky to get the bolts out of the differential with the one side (left, input side) still in the case, but I managed it (once I had it apart, I realized I could have removed the inner circlip and slid the axle out in the opposite direction). Enough expose, on the results. I am hitting size limits, so I will link to Google for space considerations. * edit - now that I'm a supporter , I will try putting them inline for future reference *

 

This thing has an 11-tooth pinion with 5 bolts holding the two halves together (partstree lists an 11-tooth pinion as the currently available replacement for the '72 1-0422 model anyway). Nothing seemed to have grenaded within the differential itself. The 11-tooth pinion gears had some mild wear, but I think they look ok. The spring had some grooves, and with the 11-tooth pinion fits VERY tight into the outer two halves of the differential. Having this apart in my hand now, I am rather surprised that I could spin the differential so easily with the hub in the video I posed above - I do not think I would spin it with the spring in just holding the shafts, like what is show in Stevasaurus's video. I loosely reassembled the differential without the spring, and could easily turn the (now open) diff by hand without the ratcheting / clicking.

 

So my current hypothesis is that the ratcheting / clicking of my video above is the small pinion gears rolling across the groves of the spring. Is the wear on the spring sufficient to warrant replacement?

 

Moving on to other things I noticed... All of the front / middle shaft needle bearings seemed ok, as did the large ball bearing on the output shaft. Both sides output shaft has scoring / pitting where they ride on outboard needle bearings just inside the axle seals. At the inside end of the shafts, there was some play but I think this is expected to allow the spring / pinion contraption to float. The inside of the case showed no marks of damage. As I mentioned before, only mild shavings on the filter screen.

 

The numbers I could find stamped onto the parts are as follows:

- 8046 on the right / brake / filter side of the case

- 8047 on the left / input side of the case.

- 80*0 (guessing 8050) on the right / brake / filter side of differential

- 8051 on the left / input side of the differential

* note all these numbers look to be Raider 12, GT-14, etc according to partstree *

 

Gear counts from input to out are:

- 90-2017 hydrogear output: ??? didn't count before I shipped it out

- first shaft is 33-tooth which meshes with the hydrogear output; other end is a 22-tooth

- the middle shaft meshes with the 1st shaft with a 44-tooth gear; other end (which meshes with the bull gear) is 11-tooth

- the bull gear is 43-tooth

- the 10 small pinion gears are all 11-tooth

- and finally the gear which slides onto to the output shaft retained by the circlip is 25-tooth outside and 17-tooth inside (and the output shaft is 17 tooth)

 

Other random notes:

- differential nuts are on the right / brake / filter side (opposite input)

- no roll pins between the two halves of the outer two halves of the differential

- the seat bolts are blind, but i could see the differential and count bolts through the ATF filler pipe

 

Stuff to replace:

- spring (maybe?)

- gasket between hydrogear and transaxle

- gasket between two halves of transaxle

- two hubs

- two output shafts (both sides)

- output shaft needle bearings (maybe? because of the shaft wear not necessarily how they feel)

- output shaft seals

- couple of wheel screws (or I could potentially just clean up the threads)

 

Any thoughts? Am I missing anything? Any other 'while you're in there parts, perhaps other / all the bearing?

 

 

ID tag on hydrogear:

 

Filings on outboard side of filter screen:

 

Filings on inboard side of filter screen:

 

Enlisting the help of a hound's nose as a final diagnosis before getting to it:

 

Right brake filter side before pulling:

 

Left / input side before pulling:

 

Don't work harder, use more tools (this was a good idea):

 

First shot with the case open:

 

Second look with the case open from a different angle:

 

Going after the stuck hub - don't work harder, use more tools (this was a bad idea):

 

2-ton OTC hub puller + Dewalt 20v 1/2" high-torque impact = snapped hub between two bolt holes:

 

First look into the differential, left / input side:

 

 

First look into the differential, right / brake / filter side:

 

First look at the front and middle gear shafts:

 

Second look at the front and middle gear shafts:

 

Grooves on spring, #1:

 

Grooves on spring, #2:

 

Grooves on spring, #3:

 

First look at pinions:

 

Differential plate with the pinons out (right / brake / filter side):

 

Shaft wear, right / brake / filter side:

 

Shaft wear, left / input side:

 

Video of differential WITHOUT spring:

IMG_2847.MOV

 

Video of shaft / differential play:

IMG_2830.MOV

 

Video of differential (left / input side):

IMG_2813.MOV

 

Video of differential (right / brake / filter side):

IMG_2814.MOV

Edited October 25, 2017 by sfjohnson722
adding inline photos rather than linked

[AMC RULES 37,134]

http://www.wheelhorseforum.com/store/category/1-redsquare-support/

[Sarge 3,463]

I'd have to say that wear on the tension ring to the diff gears may just be the click . Are the thrust washers between the axle gear and case end plate missing ? Seems like a lot of extra slop there and possibly those case end plates are worn out of spec to the axle diameter ? I've been into one of those once before repairing the axle key way cuts - had to weld on up and re-grind it to fit the key tightly , did not have nearly the extra play that your diff has in comparison . That ring I suspect is made from spring steel or at least bearing quality steel - should have to compress it to remove/install at least a little to remove it's intended pre-load to the diff gears . If the face of that ring is worn I'd suspect the mating face of the gear teeth is worn as well . From the looks of those parts either that thing has been ran low on oil or had a very hard service life...a lot of wear showing .

 

Sarge

[stevasaurus 22,872]

Excellent wright up and pictures Shawn.  We need to find or fix those axles.  I would replace that spring if we can find one...and I would replace those outer axle bearings.  Finding a set of hubs should not be expensive or hard to find in your area.  Use our classified section to look for and ask for parts.  Our vendor section also has some of the things you will need. 

 

[sfjohnson722 26]

Thank you all for your help so far. I just became a supporter, so the above posts now include the photos for reference in the future.

 

I checked a couple other things this morning and wanted to report my findings.

 

The thrust washers were present, and measure ~1.134" ID, slightly oval by maybe .003". The two halves of the differential shell (what I'd call a carrier perhaps) are loose on the axles and measure ~1.158" ID and seem quite round. The assembly order on the axle (mostly for my own reference) outboard to inboard is: shell / carrier, thrust washer, gear, the circlip.

 

The spring is indeed stiff, and I needed to compress it with channelocks to get it out. When it is in place, it seems to make contact with some but not all of the pinion gears. That is to say if you flipped it over, 1-2 of the 5 gears per side would fall out. Attempting to recombine the differential shells with all 10 pinion gears and the spring in place was challenging, and when I close this up for good will require some encouragement.

 

And I just had an ah-ha moment typing this. I incorrectly had incorrectly assumed a "10 pinion differential"  had 10-teeth on the pinion gears, and why I was surprised they were 11-tooth. But now I get that it really means there are 10 pinions gears in total (vs the 8 pinion differential) - not referring to the number of teeth. Doh!

 

Outboard side of the differential shell / carrier (left on left and right on right):

 

Inboard side of the differential shell / carrier (again, left on left and right on right):

 

More to come... Again thanks for all the help so far. And also to @stevasaurus and @Sarge (and all the other military folks on here), thank you for your service!

 

[stevasaurus 22,872]

When you go to put the differential back together, the manual will talk about the longer and shorter axle and the hubs are the same way...notice the axle shell is longer on one of the hubs then the other.    Love all the pictures Shawn.