[Br_uce_h]

Hello, I've been searching these boards for a few days and I am impressed by the knowledge and experience of the users. I didn't realize what I had until I saw the enthusiasm of the owners on these boards. I have what I think is a 1986 JD 318 with about 1300 hours on it. It was repowered by the JD dealer before I bought it about 5 years ago. It has been running great until I got it stuck in the mud a couple of months ago. At first after getting it out it was still fine. Now however it jerks when put in gear and will act like a slipping clutch then jerk back into gear. It does this cold or warm, up or down hills as well as on level ground. I changed the hydraulic fluid after the first year I owned it, and again two weeks ago. It does not seem to have made any difference. I found several mentions here about a roll pin, but it appears mine has a clamp and that seems okay. I have never had and still do not have any creep. I have no idea what to check next. Does anyone have any experience with something like this? Also I think I had better try to find a service manual for it, recommendations?

 

[Richards]

Bruce,
You might want to check the drive shaft at the rear u-joint where it slides onto the pump shaft. You may have stripped the splines on either the coupler and/or the pump while trying to extract the tractor from the mud, and under power it's slipping on the splines. You will have to remove the rear pan to get a good look at this.
Just my thought,

Richard:

The Banjo Man.

 

[littlejd]

Bruce
Welcome to WFM!!

Your symptoms sound in the lines of a cracked frame where the differential mounts. Look inside the rear wheels there should be two bolts with a strap just below the brake rods. You'll probably want to pull the rear wheels for better view. Remove those bolts and the strap to check the frame for a crack. If this area is cracked it WILL buck and jerk and there won't be any stopping it until it is fixed.

There are numerous threads here on the same problem just do a search and I'm sure you'll find everything you didn't want to hear about.

HTH

 

[jdcrazy]

Mine was cracked but has been welded, will this fix the problem??

 

[littlejd]

Tom to some degree, if the hydro linkage has play in it you might experience a sluggish hydro going up hills as the linkage will allow it to "not keep up"

If the frame is cracked I would also check the transmission mount as if it has been loose for some time it could crack the case.

 

[Br_uce_h]

Sorry for the delay getting back. I pulled the fender deck and drive shaft to check the pump splines and look for cracks in the frame. The pump splines were fine, but I found three cracks in the frame. One was at the right side rear axle mount, one was near the left front steering stop, the third and worse was at the rear of the steering cylinder. That one looked like it was about to break out completely. I have taken it to a local JD dealer to repair. He tells me it will be three weeks before he even pulls it in to look at it. I'll let you know the outcome when I get it back.

 

[3jd318]

Oh Bruce, Jus get your welder out. some reinforcment at rear axle helps. Been several articles on here about different ways to reinforce.
gp

 

[Jdodad1]

Dealer won't know how to fix it anyways.....
Taking it to a dealer is a big mistake......
He'll try to get you to trade it in on a throw away model.

 

[elankford]

I have seen these threads, and have to wonder how a crack does this. All that I can guess is movement at the crack between a pivot and the hydro. It would then effectively vary the hydro setting as the control lever mount pivot point to hydro control arm length varies. Is that how this does causes the bucking?

 

[david_a_calkins]

ED is right on ,you need to repair the cracks in any case ,if you don,t weld just clean out around the bad area vee the cracks pull the frame tight with a pipe clamp ,remove the gas tank .and battrie .place the ground on the frame and re weld it use 7018 ,or 6010 or 6011 .if you use a stick welder .lots of frames are welded and live to work again ,hope this helps . David

 

[Br_uce_h]

Believe me, I wanted to plug in my welder and have at it. Trouble is after we bought this house I never had the electrician out to upgrade the wiring and install an outlet for my welder. I called him before taking the tractor to the dealer, but he is telling me the same time frame as JD, and we know that contractors can be an optimistic group of people. ;-)

 

[Br_uce_h]

I got my tractor back last night with all the frame cracks welded up. That fixed the problem. It's nice to have my tractor back! Thanks to this forum for the help.