Loss of RWD on ME 50HX. Will drive in 4wd

foxy farmer

Feeding cattle about an hr ago and while driving shear grab into pit face I felt a sudden jolt from back axle and I lost drive. After checking wiring I realised that I had drive to front axle when 4wd button was pressed.
Transmission is working fine ie can change speeds. When I Jack rear wheels off the ground and select forward reverse neither wheel will spin. If I spin one wheel by hand the other won't spin in opposite direction.
Am I looking at a failure in the rear diff or the drive shaft to it?
Edit title should be MF 50HX

emaherx

foxy farmer wrote: »

Feeding cattle about an hr ago and while driving shear grab into pit face I felt a sudden jolt from back axle and I lost drive. After checking wiring I realised that I had drive to front axle when 4wd button was pressed.
Transmission is working fine ie can change speeds. When I Jack rear wheels off the ground and select forward reverse neither wheel will spin. If I spin one wheel by hand the other won't spin in opposite direction.
Am I looking at a failure in the rear diff or the drive shaft to it?
Edit title should be MF 50HX

I'd imagine it's the shaft to it. If diff failed I'm sure you would have serious grinding noises.

Shaft is most likely a splined shaft with a sleeve over it held with a split pin. I'm guessing split pin fell off.

Not familiar with the 50 HX but if it's like previous models should be simple enough to remove lift cover and reattach. (Assuming cab allows easy access?)

Does the 50hx have 3 point linkage? Or even just the lift cover with stubs? If it does you will need to be careful removing lift cover there are a few bits to disconnect from side cover first.

foxy farmer

After doing some ripping today it's looking like the shaft is in trouble at back of transmission housing. Opened top and side cover and spliced sleeve and split pin intact. I can twist the shaft and both wheel hubs turn so diff is probably o.k. It'll have to be split by the looks of it. Bit of a dose.

emaherx

foxy farmer wrote: »

After doing some ripping today it's looking like the shaft is in trouble at back of transmission housing. Opened top and side cover and spliced sleeve and split pin intact. I can twist the shaft and both wheel hubs turn so diff is probably o.k. It'll have to be split by the looks of it. Bit of a dose.

Great.......
Well, sounds like diff is ok. I assume when you spin a wheel, shaft inside is spinning?

There are no weird noises from transmission when you drive?
Think your Gearbox is fine too.
I think that in the transfer box one of the shafts has lost a Circlip and slipped out of position. you will probably loose all drive if it slips another bit. But yea think it will be a job for splitting.
Wouldn't recommend driving it too far with just front wheel drive, but I'm sure you know that.

emaherx

Actually forget about that, I think the output shaft from gearbox comes straight through transfer box. So if output shaft is driving the front wheels it should provide power out the back.

There should be 2 couplers in centre housing, have you checked both?


Attached diagram from parts manual of a 390, (But suspect it will be similar)

foxy farmer

Made a few calls yesterday and it turns out that it's a simple job to fix. Like the diagrams above show there's splined couplers on either end of the shaft. Take out split pin on the rearmost slide the coupler up the shaft. There's now clearance to remove the shaft.
The splines on the front coupler have been stripped and the rear coupler is very close to failing.

emaherx

foxy farmer wrote: »

Made a few calls yesterday and it turns out that it's a simple job to fix. Like the diagrams above show there's splined couplers on either end of the shaft. Take out split pin on the rearmost slide the coupler up the shaft. There's now clearance to remove the shaft.
The splines on the front coupler have been stripped and the rear coupler is very close to failing.

How are the splines on output shaft?