Hi Folks,

I found this forum looking for information on my D6 8U.

Recently purchased from an individual with the description of having a final drive issue. If moving forward with both steering clutches engaged you would never know there is a problem,
however if you release the left clutch the right track jerks and movement basically stops. When the person I purchased from delivered it he had to drive in reverse to get it to the location it is parked at now and said that it seemed to pull just fine on both sides in reverse.

I am new to the associated terminology, but hopefully I have given enough description about the issue.

Looking over parts diagrams, if I am looking correctly it looks like the transmission has one set of drive gears, that is there isn't a set for left and another set for right. My thinking is that if the left track is being driving as expected, there would be little chance of the issue being in the transmission. With all the recent rain I have not gotten a chance to do anything to the it yet, there are a few obvious steps I will take before jumping right in to the final drive.

Drain oil and check for glitter or metal debris
Assuming I have access to do so, use my bore scope to look inside the final to inspect for damage

But before I even get this far, maybe something stands out from the description of the issue and someone may have advice ?

From my understanding this machine has 4 gears, without having operated it and verified the issue happens in all 4, but going back to my understanding which may be wrong, each steering clutch takes power off the transmission equally, or am I mistaken about this ?

Thank you,
James

Suggest you find servicmans reference book to study before you start dismanteling things. Usually available on ebay. Problem is after the transmission most likely in the bevel gear/ steering clutch comparment at the rear of the machine. Under the operators seat.Or in final drive case that entails track disconected. You are in for quite a job and some heavy lifting.
best of luck WF

Definitely drain the oil from the right final drive and look for metal particles---each final drive takes power off the bevel gear shafts separately

Thank you for the reply. I have books, the seller just forgot them when he delivered, so I am picking them up later. In the meantime what I have been able to find online was guiding me away from the transmission, I was just looking to confirm this in theory.

Looking at photos on ebay service manuals gives me a much better picture of possibilities.

Fortunately I have 20 years of experience working on 1940s era industrial machinery, just big gearboxes, clutches and valves. Certainly a different type of machine here, but not beyond of my capabilities.

For the sake of discussion could you or someone expand on the thought of not pulling with forward travel but seeming to pull fine in reverse. Would there be a specific reason that would happen from experience or is this just following the symptom to the most likely culprit ?

Thanks for reading and thank you for your time,
James

I have had gears that would function in reverse but not forward---when i pulled the gear out i found that the foreword direction on the gear had rounded the gear teeth so they slipped
but in reverse the teeth were not so worn and worked---had a drawbridge once that would go up fine but kept skipping on the downward travel

Don't get in to big a hurry to start taking things apart. From my reading, you have experience the problem yourself? I am thinking there could be several problems. I am thinking a slipping steering clutch and a track jumping off the rollers. What is the condition of undercarriage?


So when you try it out have someone along side watch what the track is doing.

No dumb questions. Also hard to guesstimate your knowledge, don't want to insult you by starting to basic. But the newbies have thought it was a major problem and it was only there lack of knowledge. With such simple things as using brake as well as just pulling the clutch to make a sharp turn. If you have patient people here can walk you through fixing about anything.

KingLuxor wrote:

Hi Folks,

I found this forum looking for information on my D6 8U.

Recently purchased from an individual with the description of having a final drive issue. If moving forward with both steering clutches engaged you would never know there is a problem,
however if you release the left clutch the right track jerks and movement basically stops. 

Just a wild ass guess here. ...... I am suspecting excessive slop in the (bevel gear) cross shaft bearings.

While this condition can be easily checked  and verified  it can be  difficult and time consuming to repair.

You may be able to compensate for it and get it operational by a simple adjustment of the steering clutches. Try backing off on the free travel adjustments on the steering clutches.

Tom
 

I would suspect a broken cross shaft also known as bevel gear shaft

I saw a 3T with the teeth on the outer clutch disks so wore out when you pulled the other clutch it stopped, new disks and a drum fixed it. D6s have 12 disks and don’t cause as much trouble, D7s have 10 and wear out quicker. 17afarmer