F18D 4WD won't run

[Lee-HT]

Raised all four wheels. Shifted the small stud that is under the seat into 4WD and the rear wheels spin BUT the front wheels won't.

When the tractor arrived a couple of months ago there was a leak at the fitting of the metal hydraulic line to the rear housing. All surfaces had paint and rust. I scraped, whetstoned them and installed two copper washers. No leak. Used the 3point with no problem raising mower. The 3 point has just started to creep up some times and rise normal at others. Hyd/Tran fluid is at full level.

Please tell me this is due to a dirty screen # 194515-24930 low at the rear rear of the differential. Or a dirty Hyd/tran spin off filter #194250-48310.

 

[Norm-HT]

Are you sure the 4wd shifter is a "small stud that is under the seat"?

 

[Lee-HT]

Yes. The dealer thought it was in the middle and below my knees. I sent sent him a copy of the owners manual showing the knob below and to the right side of seat. I also sent a photo of the area he thought was where it was and there is no control there except for the 3 point hitch drop regulator knob. There are other models that do have the 4WD there. The stud connects to a 1/2" bar that then connects to the shaft going down into a control casting that I assume is a valve. With a little research the dealer found another F18 with the same set up. When I shift into 4WD it slows the engine by about 500 rpm but nothing happens to the front wheels.

 

[DAIRYMAN-HT]

Fluid has nothing to do with the 4wd. Is there a plastic or metal shield cover ing the 4wd driveshaft? If so remove it so you can see if the shaft is turning. This will tell you if it is tranny related or front 4wd related.

 

[Lee-HT]

I should have mentioned that the drive shaft to the front wheels does not turn. It is not covered.

Part two was the slow 3 point.

 

[Lee-HT]

Dairyman
The reason I wondered about the front end drive shift being controlled by the hydraulic system in that the control shaft going down into the top of the rear housing is only about 1/4" dia. My thinking was this is only a valve that engages the shaft. When you move the spindle lever in and out of 4WD the engine drops or increases about 500 RPM. Also it is at the very top of the housing and I would think the gears are somewhat lower in the assembly.

Having problems with the 3 point and the crud in the connector made me wonder if I have hydro problems. I have had problems with the FEL control pressure relief valve being corroded. (blew 4 hoses ) I cleaned the black corrosion out of it and it seems to be working.

I'm new to this kind of equipment. I have used a Ford 850 for 35 years and when you move a lever you move a gear or what ever.
Lee

 

[Aaron-HT]

The 4wd shifter is just to the left of the main shifter lever. By your left leg. I'm not sure what you are moving under the seat but it is in no way related to the 4wd. The 4wd on all Yanmars is completely mechanical - no Hyd control.

 

[Lee-HT]

I'm dumber than a rock. I jacked all wheels off the floor and the 4wd is a short lever just above the left floorboard. Someone replaced the knob with a knob inscribed PTO. In my weak defense, the Murray owners manual for the F/FX models showed the 4wd knob under the right side of the seat where the short stem is and the PTO on the left of the seat down low. My PTO lever is up on top of the pan at the left of the seat. The PTO down by the floor board didn't work anything. My one shift is down in front on the right with the other shift up near the top on the right. The 3point is back by the seat.
When I shift the under-seat stem forward this lowers the engine by about 500RPM. I thought this was the 4wd kicking in. I wonder what the stem is for. I won't use it.

I'm going to change the filter and clean the screen and maybe the 3point will stop acting up.

Thank you all.
Is there a way for me to indicate this has been settled on the main page so the posting doesn't still take up space?

 

[Aaron-HT]

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That is where many (most?) of the F series 4wd control levers are located. The FX18 must be different.

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We've got plenty of space <E>:lol:</E>