Allis HD7G Final Drive
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=64371
Printed Date: 26 Jun 2025 at 5:13pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Allis HD7G Final Drive
Posted By: NEJim
Subject: Allis HD7G Final Drive
Date Posted: 01 Feb 2013 at 10:31am
| What could be wrong in the final drive of a HD7G? I know where one is with that problem. Also have any idea of repair cost.. |
Replies:
Posted By: gemdozer
Date Posted: 01 Feb 2013 at 11:39am
| The HD7 final drive have the sprocket shaft,bulgear,top pinion,a intermediare pinion and gear and it could be just a broken bearing probleme and am still have these used parts. |
Posted By: Coke-in-MN
Date Posted: 01 Feb 2013 at 3:47pm
|
Until one looks into the case it is just a guess, what is the problem? Does the track not drive , no power to one side of machine , locked sprocket , noise from case, jumping or partial locking ? How new of a machine -
------------- Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something. "Challenges are what make life interesting; overcoming them is what makes life meaningful." |
Posted By: DMiller
Date Posted: 01 Feb 2013 at 3:58pm
 Wilie at Chartrand also has a few pieces left, his take on them was the bearing lube would get low(unchecked) and then wipe the bull gear or drop teeth from poor contact on the bull gear. Not much else in there to go wrong, I did have a busted drive hub on my left clutch when I tore it down last summer, the hub has four fingers from center to outer rim, these had all cracked and can shear away.
|
Posted By: DMiller
Date Posted: 01 Feb 2013 at 4:02pm
| One item of note, if it is close enough to me it might be of interest for a parts machine for me. I need rails, a few small items and a transmission, would be interested in the whole machine if still will move at all. |
Posted By: DMiller
Date Posted: 01 Feb 2013 at 7:24pm
 This is a final sub assembly I bought for mine as the sprocket had been allowed loose on the shaft too long. The assembly here has no bull gear it slides onto the splined area and is driven by another gear in the final case. This cost $650 and I had to pick it up, to get a bull gear was an additional $400 if needed.
|
Posted By: ctbowles58
Date Posted: 01 Feb 2013 at 8:03pm
|
there is one on southeast MO craigslist for parts. ------------- 190XT 2WD45 WF D15 D14 CA BIG10 302 & 303 bailers 77G rake 80R mower 6 plows and alot more |
Posted By: DMiller
Date Posted: 02 Feb 2013 at 5:52am
| That one has been looked at, was not running, had not run in some time. Gent that took it apart used a gas axe for the most of it, rails would have been a reasonable buy but were dozer pad rails and had sat in the mud for a few years with a lot of corrosion going on to the lower pins/bushings. It was also a earlier version than mine and while parts will interchange many do not play well. |
Posted By: Mactractor
Date Posted: 03 Feb 2013 at 2:25am
|
Most common failure is teeth off bullgear and bull gear pinion, nearly always caused by not maintaining preload on bullgear/sprocket shaft tapered roller bearings, or not replacing the straight roller bearings on intermediate shaft in time. Shock loading from things like running tracks down to the point where sprocket teeth sharpen then spin in chain links will do it. As with all tractors HD5 to HD21, when you have the track rails off them, RESET PRELOAD ON TAPERED ROLLERS IN FINAL DRIVES. That practice miminises failures. If you gonna run a 7G awhile, a sprocket shaft is good to have among your spare parts. They are a little longer than HD6 shafts and probably harder to come by |