420 hydraulic problem below

Looking at the TM for a 300 LGT, I think the 420 is similar, the charge pump draws oil from the bottom of the differential housing and up thru the filter before it gets to the pump.

Change the filter as it has possibly collapsed internally and blocking suction flow. Fill the filter as much as possilbe with oil before installing.

The only other "logical" place of flow restriction would be out of the bottom of the differential housing... May have to take the line off the bottom of the housing to see if oil will flow.

Repost if you find the problem as I have a friend with the same failure mode and his charge pump is okay too!

It would not let me post a reply below.
 
Thanks Roger. I've ordered a new filter. Could not see any obvious problems with the old one. I will take that bottom rubber hose off and make sure there are no restrictions through that.
 
The hose may be collapsing under suction. New is M72035 hose and spring inside is M111759 but would have dealer confirm.

I did not know it was a hose.
 
I had previously replaced that large( maybe 1 inch in diameter) hose that comes out of the bottom of the transmission/hydraulic casing.
 
Did it have a spring inside to prevent collapsing? Did you put a spring inside of the hose you replaced? Did you use the JD part or just an ordinary hose? If ordinary hose, it could collapse internally under suction....
 

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