Construction and other equipment - Hd7gb torque converter/transmission

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Hd7gb torque converter/transmission

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=201935
Printed Date: 23 Nov 2024 at 3:13am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Hd7gb torque converter/transmission

Posted By: Braswell
Subject: Hd7gb torque converter/transmission
Date Posted: 23 Jun 2024 at 7:06am

Good morning to all from NC…
I’m in somewhat of a diagnostic bind, the engine spun a bearing before I could test the transmission/converter functions. This is the unit that was dumping fuel into the engine and had the unusual fuel timing pin location issue. I got it running and was going to check other systems when the engine bearing let go. I’ve removed the engine and torque converter and doing visual inspections of pumps and torque converter. The inside of the torque converter looks great … I have a question about the stator inside the converter. Is this a one way stator that free wheels in one direction and locks in the other.
I also have questions about the transmission clutch packs. I sure don’t want to pull the transmission unless I’ve got to, obviously… it looks like a monster to remove… there is an inspection cover on the side of the transmission I could remove to look and measure the wear in the friction plates, does anyone have the specs on allowable wear of these friction plates . Any advise is greatly appreciated!!!
Randy

Replies:

Posted By: DMiller
Date Posted: 23 Jun 2024 at 8:20am

Same trans as in the 7G, and no, cannot even see the plate discs unless fully disassemble and No are next to NO parts if anything internally is broken. Biggest failure concern on trans is Filtration and shifting shaft seals, is a Large Suction screen behind the ported plate top right as look at face, is also a screen at bottom left and both should be cleaned while box is empty. Are three seals in each head support on the trans shafts Upper and Lower, the seals are NLA, yet a Hydraulics shop can kind of sort of match to a like kind sizing and make the oil feed to the clutch packs. this is a typical fail for these. The Gb series converter is different than the G series, not certain if has freewheel on stator.

Posted By: Braswell
Date Posted: 23 Jun 2024 at 11:58am

Thanks Mr. Miller for the response!! I’ve disassembled the converter and found there is no locking sprag in the stator.. I have some pictures I would like to post but don’t know how. This torque converter looks to be bullet proof.
You sent me an email a few months back that had all the manuals you found on eBay. I accidentally deleted it. The only manual I didn’t buy was the parts manual and ow I’m thinking I need it for pets breakdowns. Could you please look at your sent email for me
Drbraswell@triad.rr.com and resend that when have time.
Thanks again for all the help!!
Randy

Posted By: Braswell
Date Posted: 23 Jun 2024 at 12:22pm

Peeking through the bottom suction port hole I can see one of the clutch packs and with a long skinny screwdriver move the plates back and forth in that pack. I’m very familiar with other industrial transmissions and it seems to have a lot of play in those disc. I’ll remove those end caps and inspect those sealing rings and air up each pack, might tell me something before I remove the entire housing. I sure don’t want to spend money on the engine if the transmission is weak.

Posted By: DMiller
Date Posted: 23 Jun 2024 at 12:50pm

The trans is the weak spot on these along with the Track Chains, 7" pitch is no longer available from ANY providers US.

The trans style was pretty common in the 70s into the early 90s on a number of machine makes. Rockford Clutch made these against Allis Specs, Rockford equipment in other machines does not interchange. As are so few of these remaining there are extremely limited spares as to used and NOTHING new for these. I went thru my own and reman'd best I could , did fine except could not stop converter leaks as could not get the nerve to pull the engine/converter package to tear into it. The trans will still shift into gear and still pull completely worn, pistons have no limit to travel except if pack blows apart.

The 7G had a different Steering Clutch supply system than the Gb, the latter were a little more readily available but not by much.