Allis chalmers 1969 HD4 crawler loader help

H4 turns when you pull the hand clutch FIRST and use brake 2nd 
It is not a hydraulic applied clutch like the 653 / 655 
there is a adjustment for both brake application and for the clutch throw .
 VEER right or walk right slowly - big difference as machines seldom move in a straight line for long distances . Fwd/Rev is controlled by lever on left side on tank which sends hydraulics to clutch pack to control neutral and or Fwd / Rev direction.
 As it uses a hydraulic torque converter and a forward and reverse shuttle clutch to drive a 3 speed transmission - the power then is routed through the ring and pinion to a stub axle that indexes into drive plate in steering clutch unit - which is also the brake bend hub with band around outside . 
 Clutch can be a multi disc or single disc with auburn pressure plate 
This feeds through it's hub to a single reduction spur and bull gear - bull gear is supported by 2 timken bearing on axle shaft - known point of wear is outboard axle bearing which will move and eat into case requiring removal of case and machining the case for new bearing housing . 
 Access to steering clutch area is through plate which is under the side fuel and hydraulic tanks .

Edited by Coke-in-MN - 04 Jan 2021 at 11:18am

Thank you very much coke for the reply, I have read may of your reply’s to question and it’s staggering the amount information you have. Again I apologize ahead of time if it seems like I do not understand some of how power flow happens. I do feel like I have a light grasp of shuttle clutch,steering clutch and brake operation but do not think after a few weeks of looking at owner’s/parts/service manuals that I can say ya I understand this machine. When going forward machine will very quickly turn right with no operation of brakes or steering clutches. I would say it is almost doing donuts. Assuming I wanted to turn left I would pull left steering clutch handle and apply brake but the machine just stops then. At this time I would say it cannot turn left. Also not sure if can remove steering clutch with removing tracks or can it be done with track left on ?

I think the only side getting power is L/H. That being said I’m trying to figure out how I can maybe see if there is power going to R/H steering clutch. Do not want to start tearing down to do steering clutches not know what real problem is. Am wondering will I be able to run machine with hydraulic tank off If that isn’t stupid idea so I can see what is actually happening when forward shuttle applied. Was thinking if I remove seat might be able to see what’s going on in there thru brake adjustment hole that I think I see in the manual. Would I be wrong to think that I will see the shuttle clutch drum rotate when forward clutch applied? I thought if I could tell if power is being sent to steering clutch then I could narrow down what side the failure is on transmission side or steering clutch side if that makes sense.

Ya likely try and free it up and see if I can get a better understanding by see what the left side is doing that the right side isn’t. Hoping those brake adjust ports are actually a thing. More than once I’ve had thing apart and then been like wish would have checked ............. while it was running. Still wondering if tracks have to come off to take steering clutches out. There is a decent amount of videos out there for JohnDeere steering clutches, no such luck with these.

are you anywhere close to columbia mo

Each section is a separate operating part - steering clutches are their own section and a   flange in there drives the top gear of the single reduction drive . 
Attaching the ring and pinion to clutch section is a small axle shaft that index into clutch hub and is kept from moving by a round clip that indexes into that shaft . 
 If you have drive only on one side then power is not reaching the track - Next question is WHY 
 So opening up the steering clutch area and checking IF anything in that compartment is broken or not working - It might be easier to set machine up on blocking with tracks free of ground to do some checks when applying power or checking drive components. 
 What I have done is using loader raise machine off ground , slide blocking under track about 1/2 distance of track - lower machine so it rocks forward - block under back of machine to tight fit to drawbar area - again use loader to lift front of machine - remove blocks from under track and then block front of machine up so tracks are free from floor .Now service on all parts can commence . 
 No the track can stay on unless there is a problem in single reduction case - and even then that can be services without removal of track or splitting of track as rear sprocket is bolted to drive axle . Drive axle is held on from inside of rear housing with nut on end of axle shaft within a small housing for bearing - cover held on by snap ring and internal shimmed to preload the bearings 

To me something just does not look right in the last picture. the fork that works the through out bearing appears to have the bearing up against the fingers of the clutch. My problem is if i am seeing correctly the non splined part of the axle is inside the clutch pack and the splines located in the bearing may be the splines that should be in the transmission . If this is correct it would indicate the axle has shifted toward the outside because the splines are on the end of the axle on both ends and no smooth axle should be seen between the splines and the clutch pack .  could be wrong and seeing things but just my observation. 

The axle shaft slides into the rear housing and into ring gear housing , this allows access to the clutch pack . Couple different clutches were used - mine had a single plate (like a truck clutch) and fingered pressure plate (Auburn style) others have said they had multi clutch plates more like a HD5 or large machines use.
 If you slide the axle shaft into housing it is a good idea to put a tie wire on it so it can be easily pulled back out of housing or you will be cussing as you try to get it back out .