Opinions of a D6 4R and 5R

I plowed with one in the Spring of 57 for a month.

As Pete says they don't have the snort of a 9U but never the less they are a nice comfortable tractor.

Pulled a 5 bottom whereas with the 9U we pulled 6 bottom.

Later on, Green Giant found that ganging the plows a 9U could pull 9 bottoms as easy as as one 6 bottom.

Depending on the s/n's your comparing there is not that much difference between the 4R and 9U. Early versions are about 10 hp apart, full load rpm is the same at 1400 rpm. Weight is within a couple hundred pounds.
A lot of similarities except engine between the two. Governor is a little snappier on the D4600. Production numbers are much smaller than the 8/9U's.
GP you really should look at some facts before spouting off an evaluation.

I love the 3 cylinder tractors and then the 4600 engine it has a note all of its own. I don't have a u series but have used other people's and I will have the 5r any day! I guess if they were all perfect they would still be making them.

The horsepower is the real difference from a R to a U series D6.The same track, transmission,and clutches.Yes OM I understand the transmission gears are different because of different RPM's.Blind folded sitting on the seat the throttle lever is the only thing I can think to give a chance tell a difference,as the air cleaner is in front of engine.

The dozer blade and the speed of its control is going be what separates one of the R or U series D6 from another,so as much difference within each series as from a R to a U.The 3 cylinder D6 is a different animal with balance and steering control levers that are not hydraulic assisted.

A R series master clutch takes more maintenance than U.The U's are enclosed so much less dust to deal with. I was told to oil the linkage daily on a R,then you have to wash all the mud off ever 3 or 4 days depending how much dust you are in.Have had a clutch that would not release because of dirt binding the linkage,not a good felling to not be able to stop the thing. Never had to do this with a U series dry clutch.This would not stop me from having a R series D6.

Cut my teeth on an early R with a LaPlante blade on it! I was always told it had later model Crank, Piston & Liners in it so it had a little more snort! It was pretty popular in the PA oil patch for quite a long time. It seemed to have good power for pioneering roads and moving drill rigs. Till I drove a newer 9U! What a tractor that was! If I had a chance to get a decent one like that "old girl", I'd do it!

as an owner of both a 5r, and 3 9u's, there is very little difference between them. the 5r is the same gauge as the 8u, the 4r is the same gauge as the 9u, seems backwards but that's what it is. in my experience, pretty much everything from the flywheel back is interchangeable, i took an early 9u transmission and used it as parts in my 5r, all the shafts were the same, but there were a couple of different gears internally, i think 75% of them were same part numbers. i did this before i had parts books so i was really just fumbling in the dark. the dry clutches between the early 9u and 4r/5r are identical in operation and adjustment. the 4r and 5r have a fully enclosed dry clutch, there are two rubber seals that seal the flywheel housing to the transmission case that i found disintegrate when they get oil soaked if you have a leaking front seal on the tranny input shaft.

the d4600 is a sweet running engine, yes it has less horsepower (10) then the early d318, but it runs quieter. the pony's are almost interchangeable, you would have to change the rear timing cover, the mag, the exhaust manifold to swap the pony from a 9u to 4r/5r machine. some other small differences are the carb adjustments, and maybe the air filter.

the mags between a 4r/5r pony and a d318 are not interchangeable. the u series use a wico mag, while the 5r/4rs use an eiseman. the wico won't work on the 4r/5r as the impulse coupler doesn't catch due to the orientation of the mag mounting. i have original CAT servicemans reference books and an operations manuasl that cover the 4r/5r and the 8u/9u series tractors all in the same book showing that they are very similar. you can take a hardnose from a 9u/8u and install it on a 4r/5r as they are the same attachment group in the attachment book i have. the 6a or 6s blades are also interchangeable if you are swapping between an 8u/5r and a 9u/4r machine due to the track gauge.

my 5r is my favorite, i'm not sure if that is sentimental, or because you don't have the aircleaner in your face and just have a nice lever for the engine speed control in front of you. i think the visibility is slightly better on my 5r then on my 9u's.

i have a bates hydraulic blade with rear mount beegee pump on my 5r, not as nice as a front mount hydraulic system, but still very functional. the cat hydraulic and 6s/6a hydraulic or cable blades are nicer to use and easier to finish grade with then the bates system. the bates blade itself is much easier to adjust the tilt and angle then the cat is. trade-offs. LOL

here's two pics of my 5r sn 5r189 through extensive hours of research, i have not found any 5r's that are known to be around that have a smaller serial number. i bought it from the original owner who purchased it brand new from union tractor in Lethbridge Alberta in 1942 [attachment=34224]Hauling cats Oct 2010 008.jpg[/attachment][attachment=34225]Hauling cats Oct 2010 007.jpg[/attachment]


and a pic before and after of one 9u that i fixed up and sold. serial number of the tub and tracks was 9u4620sp and the engine came out of 9u6222


[attachment=34226]aug 2 2014 057.jpg[/attachment][attachment=34227]June 8 2015 019.jpg[/attachment][attachment=34228]June 8 2015 018.jpg[/attachment][attachment=34229]June 8 2015 017.jpg[/attachment][attachment=34230]June 8 2015 016.jpg[/attachment][attachment=34231]June 8 2015 015.jpg[/attachment][attachment=34232]June 8 2015 014.jpg[/attachment]

4620sp had a front ccu 6a cable blade and hardnose, when i swapped the engine over i installed the hydraulic hardnose , c-frame, fuel tank and fenders from 6222, and the canopy from 9u26206