Opinions on maroon 7000 with reverse gear rattle

you can change reverse idler without split. if problem on counter shaft the gear is made on the shaft. If you don't want to chance some money and using reverse a lot like on a round baler I would run.
Albert

They had a bad reverse idler gear. That could be what you're hearing? You can fix that without splitting the tractor.

Access the trans by removing the top cover and have a look...

Buy it! It's still is cheaper to fix than buying new.

Could be four things: #1. The top gear has a chipped tooth because someone jammed it in park while still moving.  #2. The idler gear is chewed up from poor engagement over the years due to the gearshift hitting the seat. #3. The bottom gear missed heat treatment when built and is now worn out. I had one like this. #4. Operator constantly grinding it in gear damaging all three gears, like a round baler tractor ?? All are a big deal to fix except for the idler gear itself.

And maybe drain the oil from the transmission cavity. The drain plug is behind the fuel tank. About 2 gallons lost.

looks to be in good shape, but with black chassis decals makes me think it's been repainted. At that point I begin to question the accuracy of any hour meter. 
If it's in good shape, and priced right, hours aren't as big a deal as people make them out to be. Due to it's age, things will likely need attention regardless of said hours. 

Kevin in WA wrote: There were a few maroon belly 7000s made in early 78, Norm Swinfords book says 393,  I know of one maroon belly  from the factory with the large decals, i'm guessing its one of those. Being there were a few hundred of 7020s and 7045s built in late 77, that may explain the switch to the large decal before on the 7000 before the mechanical changes were ready for production on the black 7000 in 78.

The heavy axle was an option.

Maroon tractors were also available with 8 bolt hubs, I have seen 3 of these.

I still question it being a 1978 build. Maybe a mix or a replaced rear end. Allis was selling all its excess Accousta I cabs in the Fall of 1977. Dad bought a new one at a consignment auction that had 6 of them from Allis Chalmers and he mounted it on his 190XT that he also bought in 1977. Anyhow it happens that the cab Dad bought specifically says on the cab tag that it was built for the 7000 tractor and meets California roll over protection regs.

Edited by Lonn - 19 Apr 2020 at 10:00pm

According to Tractor Data, model year 1978, started with serial number 6373, with the change over occurring at serial number 8000.

To change that reverse idler gear, you need someone with small hands. There isn't much room !!!

I've done the reverse idle gear in mine.  I believe it is a softer metal (not heat treated maybe?) than the other two gears, because mine had about half of the tooth width ground off and the other two gears didn't have any signs of wear.  One thing to note about it, the bushing needs to be honed to size for the idler shaft.  You need to take off the transmission top cover and the rear end cover to undo the retaining plate inside the rear end, if my memory serves me correctly.  Then slide the shaft back, take out the gear, pull the shaft the rest of the way out, take the new gear and shaft to a machine shop to be honed (you don't want to use a brake cylinder hone or the like, as that can leave abrasives in the brass, I believe the machine shops will basically ream it to spec based on the shaft diameter, but I wasn't there when they did it).  Reverse the procedure and you have it back together.  I think the spec is in the service manual for sizing the gear.  If you get to that point, shoot me a message and I will scan that page to you.