CAT D7F

[Troxtell1986]

I just bought this dozer and after countless hours of searching cannot find any info on it. Could someone please tell me what year and engine is in it by the VIN number. 94N4599

I was told this is a really low hour machine. It was a barn find that had been sitting for years with trees growing through it. I put a starter and batteries on it and it unbelievably started right up.

The old man I bought it from said he has known the machine since new. It was bought for a under ground cable job for the company he worked for and he then later bought the machine from them and added the blade. I know some of these are known for weak transmission. Is this one i should be concerned with?

 

[Dave Neubert]

The F I think was the first to use the 6 cylinder but still used the 4 cylinder transmission and they were hard on transmissions. I believe it had a lot to do with the difference in RPMs

 

[Kyfarm]

that thing is awesome! more pictures please.
did someone run weld all kinds of up and down the pusher bars?

I bet that cable spooler (if that's what it is) on the back is a pretty rare attachment.

What are you gonna use if for?

 

[Troxtell1986]

that thing is awesome! more pictures please.
did someone run weld all kinds of up and down the pusher bars?

I bet that cable spooler (if that's what it is) on the back is a pretty rare attachment.

What are you gonna use if for?

Ill get some more pictures later and yes, those are welds. I guess to help with wear??? The attachment on the back was for burying cable. Before he added the blade it had a spool holder on the front and the cable ran over some rollers on top of the cab and it would bury the cable as you drove.

Ill probably attempt to dig a pond with it on our small farm and just play around with it. I really just bought it because i thought it was in good shape and priced right.

 

[Nige]

A few bits of information that might help you to fill in some of the blanks. I'm sure it is not the full story but at least it is a start.

The 94N (and 92E built in Japan) D7F was introduced in late-1969 to replace the D7E. It was fitted with the 4.75" bore D333 engine that is the predecessor to the 3306. Tractors up to 94N5191 (if original) will have the same engine S/N the as the tractor S/N. Tractors up to 94N5191 were fitted with the "early type" of D7E low-speed, high torque transmission.
The D7E planetary transmission operated at quite low rotational speeds (around 1200 input RPM) and could carry high torque loads.
In comparison the engine in the early D7F tractors was running at somewhere close to 2000 RPM.
As a result, these transmissions were considered not as reliable or cheap to run as the later D7F's (94N5192-up) that were fitted with the 2P-series high-speed, low-torque transmission that is identical to a D6C transmission.

When the D7F drivetrain was modified at S/N 94N5192, the D6C transmission was fitted, and the reduction gearing on the rear of the transmission housing was changed to allow the transmission to run at much higher input speeds more in keeping with the RPM the engine was turning out. At the same time the engine was changed from the D333 to a 3306PC model (3N engine S/N prefix).
Despite the 2P transmission being smaller than the early type D7E transmission fitted ex-factory to machines up to 94N5191 it is a far more reliable and cheaper-to-maintain transmission because it rotates at higher speeds with lower torque loads more in tune with the engine RPM.
There was also another transmission update at 94N5660 but I have no specific details regarding exactly what it was.
See illustration below. This is what the latest "high speed" version of the D7F transmission looks like.

 

[John C.]

Serial number given is a 1972 vintage I had one of that vintage in a fleet I maintained in the eighties. Third gear was locked out on the transmission linkage. Machine had a 3306PC. We never had transmission problems. Machine worked very well for years.