Backhoe JD310 clutch/reverser questions - reverse works, forward only in 1st - tractor split

[gondiggn]

Plain JD310, early 70's backhoe/loader. I bought it a couple years ago and just now getting around to working on it. All hydraulics work, 3cyl. diesel engine runs great. Rear seal is shot, had to split anyway. It runs, shifts and pulls up hills in reverse but will only move in 1st gear forward on level ground. Main clutch is oil soaked from rear seal, I had to strap a tub under it to catch oil while moving it.

Inside the forward clutch assembly, the 3 clutch disks and 3 plates check within a few thousandths of spec, they look like they were just replaced. The clutch piston(R39115) outer ring seal(R39116) is cut almost through, probably from last time it was taken apart and forced back together. Same with the inner ring seal(R39117) it is also cut at 3 places and a 2" sliver of rubber was shaved off and under piston when I took it apart.

My questions are: Where do I access the reverser? If I can go in reverse but not forward(other than 1st on level ground) could the problem still be in the reverser? Even though my forward clutches are like new? Does the reverser clutch disks just act as a brake? Everything I read online with similar forward issues says reverser, reverser... but I am not sure how it operates in conjunction with the forward clutch pack. I know basically what it does but I am confused as to how I can go up hills in reverse but almost nowhere in forward and my forward clutches do not appear to be the issue. So far, I ordered a new main clutch since old one was oil soaked. I ordered parts,service and owners manuals.

Since both seals for the piston in the forward clutch assembly are cut/sheared, wouldn't this cause slippage while in reverse also?
Any thoughts, comments and suggestions would be greatly appreciated. Sorry if I repeat myself, just want to be clear on issues.

 

[beenthere]

:welcome: to TBN
Do you have the service tech manual for the 310?

 

[gondiggn]

yeah, just got it today

 

[Zebrafive]

Forward clutch pack of the reverser will not affect reverse operation even if they have failed.
The outer body (clutch drum) of the forward clutch pack is flywheel driven. The cutch shaft is splined to the inner clutch hub. The clutch plates, when engaged, couple the outer body with the clutch hub and clutch shaft turns.

The outer body of the forward clutch pack is also splined to the planet pinion carrier, so it is also turning. The clutch shaft has a gear on it midway that the planet pinions engage. The planet gears also engage a sun gear, which is free to turn until the reverse brake is applied. The reverse brake restrains the sun gear, which forces the planet gears to rotate the clutch shaft through he gear that is on it the opposite direction that the engine is turning.

Short version, a failed forward clutch will not affect reverse operation as long as the reverse brake is working.

I think you are confusing reverser with reverse brake, which is only one half of the reverser. Which is both a forward clutch pack and reverse brake pack. As you have found the forward clutch pack piston has failed seals

 

[jd110]

Zebrafive has explained it very well. As far as access, you need to split the transmission housing from the clutch housing to work on the reverse brake. I think by replacing the forward clutch seals, you should fix your problem. Be sure to take a close look at the bushing in the clutch housing that the forward clutch rides in. There are sealing rings on the clutch drum that ride in that bushing and sometimes that bushing gets grooves worn in it. Replace the sealing rings as well as the bushing if it has groooves.