4wd Not Engaging on Kubuta L355SS

[grayw0lf]

Since I bought my tractor a few months ago, it has seemed on occasion that he 4wd does not engage easily/fully. After using it quite a bit this weekend, its not engaging at all. My land is way too steep for 2wd.

So, after reading quite a few posts on here I've come up with the following:
1. Raise the wheels off the ground to remove any possible driveline binding & try again.
2. Make sure the PTO is disengaged & play with the clutch a bit.
3. Backup & try again.

More background:
a. The lever does not seem to go all the way down, as it seems it should.
b. There is not the characteristic driveline noise when in 4wd
c. This makes me believe the 4wd is not engaging.

Recent work, thought I do not Think its related.... but it is recent changes, so who knows...
1. I changed the hyd. oil & put in a suction line filter in place of the messed up oil screen setup.
2. I replaced the oil seal at the front left wheel.
Everything ran fine in 2wd & 4wd for a few hours before it started being more problematic to engage 4wd.

Any suggestions would be greatly appreciated.

Thank you!

 

[rbargeron]

Engagement of the L355ss fwd is just by sliding one gear into mesh - real simple - not like a road vehicle. It's very unlikely that anything you did is affecting fwd. To test basic front drive function: (1) raise the front wheels with the loader, (2) shut off the engine, (3) put the trans in a gear (4) engage the fwd lever (5) try to turn the front tires by hand. Turning one should turn the other the opposite way. Have someone hold one wheel down contacting the ground then try to turn the other one - if the fwd is connected it will be locked. If it spins freely something is not engaging. Could be one of the couplings on the front drive shaft is bad, or there's a problem in the front differential, or cracked welds or bends in the fwd lever linkage are preventing the lever from fully sliding the gear into mesh inside case. Let us know what you find. As always, prompt cheerful refund if info is bogus....Dick B

 

[grayw0lf]

I'll have to give that a try, thanks rbargeron.

It'll be Sunday before I get a chance to check it, but I'll update w/ the results.

 

[grayw0lf]

Okay, so I finally got the tractor back home where I can work on it. (Thanks Brand Spankin' New 2001 F-150 w/ only 136,500mi).

I thought I'd have good news to report, but it is mixed. I found out why 4wd wouldn't engage. There was a small piece of metal lodged between the shift fork & the wall of the 4wd housing that was preventing the shift fork from moving all the way over & engaging 4wd. The piece of metal appears to be tooth off of a gear. The gears in sight of the 4wd case all looked good. It could have come off recently, or it could have come off years ago & was flushed to the 4wd case (lowest point, bolting to the bottom of the transmission case) as I recently changed the trans/hyd oil.

Problem now: Its noisy! The 4wd makes the usual noises when engaged.... no problem there. The noise is coming from the rear end... rather far back. It almost sounds like its coming from the PTO area, though the PTO when engaged in neutral makes no odd noises. I hope its my paranoia, but I think its too loud for that. There have always been noises coming the rear when in a high gear, but now its much louder in every gear.

The 4wd case just bolts on, there does not appear to be any sort of alignment to be done. If there is, I couldn't find it in the Kubota shop manual. Maybe I missed it, but I couldn't find anything related specifically the 4wd.

Any suggestions are much appreciated! :banghead:

 

[grayw0lf]

A touch more info. The sound is speed dependent & consistent.

 

[boggen]

piece of a tooth from a gear? that doesn't sound good! it could be a broken gear, to a cracked shaft or both?

looking at...TractorData.com Kubota L355 tractor information ((assuming SS in model number stands for shuttle shift transmission))
made between 1982 - 1987, it is well past warrenty, and really can't blame anything on stuff, from initial manufacturing that might of been left in the machine during putting it together. so ya most likely looking at a something broken / cracking / splitting / worn out some place :/

if you have the knowledge, concrete floor in garage with floor space, and correct tools and machines to split the tractor. ya might give it a go. tractor data stating 2700lbs. i would imagine some heavier duty cherry pickers vs the cheapest cherry pickers might do the trick, if ya need to split the tractor. i would imagine the shop manual goes through steps of how to split the tractor along with putting it back together. if ya got good habbits of keeping track of stuff, "putting bolts/nuts/washers/screws" back in were you take them out, as you pull stuff apart. ya might be able to getter done, more so if ya have a friend that can help out during the actual final stages of splitting the tractor.

here's to ya in hoping it something that doesn't require you splitting tractor or having some local tractor repair place do it for ya.

 

[rbargeron]

........Problem now: Its noisy! The 4wd makes the usual noises when engaged.... no problem there. The noise is coming from the rear end... rather far back. It almost sounds like its coming from the PTO area, though the PTO when engaged in neutral makes no odd noises. I hope its my paranoia, but I think its too loud for that. There have always been noises coming the rear when in a high gear, but now its much louder in every gear........

Can you describe the type noise it makes? Any vibration with it? Worse under load? Can you tell whether it seems to be toward one side or the other (in the final drives)? Do you know about the tubing stethoscope trick? A length of 1/4" or 3/8" tubing can be used as a stethoscope to locate noises. Wrap one end with something to protect your ear and hold the other against the housing in various places. Works better with the tractor not moving - but jacked up and running in gear, with wheels turning. If there's a bad bearing inside you'll hear the roughness through the tube as you get closer to it. (customary safety warnings apply)

Your comment about 4wd noise being normal didn't seem right for the tractors I've had. My L345 and L355ss gearboxes are smooth and quiet in 2wd and 4wd. No alignment tricks needed - clearance in the couplings takes care of it.

Did the metal piece interfering with the 4wd shifter come out? Ok now?

 

[grayw0lf]

Can you describe the type noise it makes? Any vibration with it? Worse under load? Can you tell whether it seems to be toward one side or the other (in the final drives)? Do you know about the tubing stethoscope trick? A length of 1/4" or 3/8" tubing can be used as a stethoscope to locate noises. Wrap one end with something to protect your ear and hold the other against the housing in various places. Works better with the tractor not moving - but jacked up and running in gear, with wheels turning. If there's a bad bearing inside you'll hear the roughness through the tube as you get closer to it. (customary safety warnings apply)

Your comment about 4wd noise being normal didn't seem right for the tractors I've had. My L345 and L355ss gearboxes are smooth and quiet in 2wd and 4wd. No alignment tricks needed - clearance in the couplings takes care of it.

Did the metal piece interfering with the 4wd shifter come out? Ok now?

The metal piece interfereing with the 4wd shifter came out fine. The noise is very speed dependent. I'm not noticing any vibration & can not tell if its one side or the other. Perhaps i do need to put it up on jackstands & give it a listen.

My 4wd has always been a bit noisy (since I bought it last fall).

My best theory is this... When I sealed up the 4wd case, I used RTV silicon & not a paper gasket. I wonder if the 4wd gasket provided about 0.30" clearance & without the gasket, there is less clearance & more pressure on the shaft & therefore, its noisier. The rear has been a touch noisy since I bought it. But now its noisier in 2nd gear Hi than it normally is in 4th gear Hi.

I am starting to wonder about the possibility of a bad bearing.

I think I know the answer to this, but I'm going to ask anyways.... The rear is lubed by the transmission/hyd oil... correct? There isn't something I'm terribly missing somehow?

 

[rbargeron]

The gasket may have made a difference in gear engagement of 0.030" but they are straight-cut spur gears so it should not cause them to run out of clearance. If the noise has been affected there may be some nearby gear or bearing damage that's causing it. Is the oil clean? Grey sludge in it would indicate ground up gear or bearing debris. Usually if a gear has a broken tooth or two the bad area "clicks" every time around. If a bearing is bad the roller balls can fall to the bottom of the case, allowing shafts to deflect under load and gear engagement to become loud. Kinda sounds like what's going on here. On the good side splitting a L355ss is not a huge job and the ball bearings are not expensive.

Everything behind the bellhousing is one oil reservoir - all the way to the back. Holds 7 gallons +/- of hydraulic oil. Did that much come out when you drained it to work on the 4wd case?

 

[grayw0lf]

I hate to admit that it sounds like I have a bigger job on my hands. I got the proper gasket yesterday, it was quite thin & likely not enough to make a difference. I did get about 7gal of hyd oil from it. I had just changed the oil when I put in a suction line filter cartridge. The original screen filter housing was previously badly damaged (when I bought it).

I do have a clicking when in 4wd, like you suggested could be from a missing gear tooth.

I hate to admit that it does sound like a bad bearing somewhere along the way. I need to put it on axle stands & listen w/ a hose upto my ear when in gear. But first, a trip to the beach this weekend!!!