Jinma 254 4wd

rkevis · Sep 5, 2005

I pushed over a small tree and ended up catching the front right tire on a trailing root.
The tire was unable to turn because of the root ,the left was still turning.
Now I have no four wheel drive .
I jacked up the front and I can turn one tire and the other turns the other way and I can turn them freely with the 4wd engaged and the transmission in gear.

What Happened here?
thanks
Ray

Affordable · Sep 5, 2005

Sounds like the steel balls that drive the 4-wheel drive may have come out,slide back the cover on the 4x4 shaft on the front side,watch out for the balls if they came out they are going to hit the ground,there is a spring.washer,circle clip,and either 6-8 balls not looking at a manual.they fit in the 4x4 coulper.Let me know if you need more help

Tommy
Affordable Tractor Sales

rkevis · Sep 5, 2005

Tommy
Are the balls in the back side of the transfer case,or the front of the differential on the front axel?
thanks
Ray

bruce1966us · Sep 5, 2005

When you turn one wheel the other should turn in the opposite direction. The wheel with less resistance always turns before the other.

greg_g · Sep 5, 2005

( Are the balls in the back side of the transfer case,or the front of the differential on the front axel? )

Two sets of balls Ray - one set on either end of the front drive shaft - located inside the shaft housing, as opposed to being part of either the front diff or transfer case. Relative to your question, that puts one set in front of the transfer case and the other on the back side of the front diff

If it helps, I've uploaded the exploded parts diagram.

//greg//

RonMar · Sep 6, 2005

While rolling one wheel in one direction, the other wheel should roll in the opposite direction. That is a good thing as it says there is most likley nothing wrong with your front axel, at least not with the differential and wheel drive gear assemblies.

Instead of using "U" joints on the ends of the drive shaft like most Autos, Jinma uses ballbearings that ride between grooves in a shaft and grooves in a cup assembly over the end of the shaft, to give the shaft some flexibility. This is similar to the CV joints used in most front wheel drive axels. The front drive shaft has them on both ends. See the pic on this link to John's Jinma site. http://johnstractor.homestead.com/files/TransferCase.jpg

The shaft has grooves on the front end that mate with a cup on the front axel input shaft. The rear of the shaft has a spring loaded cup that fits over the grooved end of the transfer case output shaft. Something could have happened to this assembly to allow it to loose it's marbles.

Loosen the clamps that hold the driveshaft cover tube in place and telescope it together to expose the shaft couplings at front and rear to inspect for damage. As mentioned look for loose ball bearings(there are 6 on each end) in the cover tube. If this is the case, something could have caused the shaft to over extend and drop the balls out into the cover tube or something could be broken with the spring mechanism that holds them in place while the shaft moves. If it came apart under load, there will probably be some damage to shaft grooves or cups. A hint for re-assembly is to use bearing grease to hold the balls in their grooves in the cup while you slide things back together during assembly.

Hopefully this is the problem as it is the easiest to work on. If the drive shaft is in order you should be able to rotate it, with the front wheels in the air and one wheel or the other will rotate. If you stop/block the wheel that rotates, the other wheel should then rotate when the shaft is turned.

If all is well with the shaft and front axel, the problem lies in the engagement pawls and front drive gear located in the transfer case housing. You can inspect the 4WD engagement claw and drive gear assembly fairly easilly by removing the creeper case top cover.

Good Luck.

rkevis · Sep 6, 2005

OK The balls came out ,all 6 -didn't loose a one .
The shaft end is damaged, the c clip and maybe the cup .
I pulled the roll pin in the front but but the piece with the cup will not move on the front shaft so I can't get the drive shaft out .
Any suggestions as to how to remove the drive shaft and who's got parts?
thanks
Ray

greg_g · Sep 7, 2005

( Any suggestions as to how to remove the drive shaft )

Take another look at that diagram I uploaded. That rear spring may be holding you in place up front.

//greg//

RonMar · Sep 7, 2005

I think you need to remove the shaft from the rear end(transfer case end). That end has a cup on it that is held toward the rear(over the transfer case output shaft) with a spring(parts 8 and 17-19 on the above linked/attached diagrams). You should be able to compress the spring and slide that cup forward till it clears the end of the transfer case output shaft. You should then be able to lower the rear of the shaft and pull the whole shaft assembly back out of that front axle cup.

I figured there would be some damage, this type joint dosn't usually just fall apart. When they fail under load, it is usually pretty catostrophic. Either the grooves on the shaft end failed and allowed the shaft to strip past the balls/grooves and drop the rest of the balls into the tube, or the cup cracked/split under load and allowed the shaft to strip past the balls/grooves. The sliding cup on the rear end could have got stuck and didnt hold the shaft under enough pressure to keep the front end firmly seated in the axle cup or there could be comething not right with your front axle mounting that allowed enough for/aft(pitch) movement to hyper extend the shaft past the limit of the rear spring cup 's ability to hold the two together properly.

rdbrumfield · Sep 14, 2005

If the front still spins a tire you have 4 wheel drive. The frontend does not totally lock up so both tires have to spin. When turning the tires when off the ground, when locked in fwd one will go forward and one backward. try taking it out of gear and having someone on the other tire turning it the same as you do. You will see that they will turn free, they are not engaged to the main trans.