ALLIS CHALMERS 7040

[TCRANCH23]

I have a 1976 Allis Chalmers 7040 with the power shift transmission. I bought it about a month ago from a guy who had issues with the fuel injection system and he let it sit and didn't mess with it. I got the fuel system issue resolved and I was changing the differential oil filters. I replaced the filters and refilled the system with the 16 gallons of oil the manual calls for. My issue is the oil isn't going down to the two sight glasses and if you look down in the oil fill tube you can see the oil at the top of the oil fill tube. Is there something that could be blocking the oil from running all the way down or did I miss a step in refilling the differential oil? I used the tractor supply equivalent of Allis Chalmers 821 oil.

 

[Harry in Ky]

Most likely the sight glasses are filmed over on the inside and you just can't see the oil through them. Very common problem on those tractors. Has been since they were new. You can unscrew them and clean the inside. They WILL break if you get too hard on them, which is easy to do if they haven't been removed in years.

I used a pair of slip joint pliers, just put the end of the pliers over the glass and against the two ridges. Don't squeeze the glass, just use enough pressure to keep the pliers from jumping over the ridges.

 

[DrAllis]

You are adding oil to the hydraulic system, which is the differential/final drives. There are THREE drain plugs to this compartment along with the two filters under the belly. Make sure you use only AGCO hydraulic filters and be sure to transfer the screen inside the filter on the left(ladder) side. Get an OWNERS manual to be sure you know what you are doing. 16 gallons isn't enough if done correctly. Book says 17 and it takes all of that. You have NOT drained the THREE drain plugs !!!

 

[TCRANCH23]

I did drain all three drain plugs and I am using agco filters. I
have an owners manual and have ordered a service manual. I
cleaned the sight glasses so that is not my issue. For some
reason my oil is stuck on top and will not drain down like it
should.

 

[DrAllis]

(quoted from post at 18:15:04 04/26/23) I did drain all three drain plugs and I am using agco filters. I
have an owners manual and have ordered a service manual. I
cleaned the sight glasses so that is not my issue. For some
reason my oil is stuck on top and will not drain down like it
should.

I cannot fathom what is going on here and I know these tractors like the back of my hand. Is the tractor sitting perfectly level ?? If what you say is true, if you gently remove the top sight glass, oil should be running out of it !! and if oil runs out of the top sight glass, let it keep running until it quits !! You are now at the correct oil fill level. The three drain plugs that were to be removed are close to each other. The owners manual shows their location.

 

[DrAllis]

What have you got figured out ??