I ran across this D-7 Cat locally today. It has a 4 cylinder D339 engine and a power shift transmission. The dozer is tight and in very good shape. It has been on light farm duty since the early 80's. This machine is a little bit bigger than what I have been looking for, but the price and being local has made it an option. I only need it for heavy pushing and I have a lot of it to do. I have been told they have put 2 different power shift transmissions in the D-7's and I'm assuming this would be an early one. Would this be a good machine, heavy pushing and slopes? Thanks.
Is it an E or F model? There is another post in the 'dozer' form titled D7F. Good read on those machines. Get the folks here a serial # and they will give some advice regarding your machine.
I was unable to find what I think to be a good serial number, but what I did find on a tag on the bottom of the dash was 1841255 with the letter E under it On the hydraulic tank there was a tag that had a 43H48A1 and the very back of the tractor left hand side there was stamped numbers 48A12562. By calling a friend at a CAT dealership he went into the legacy numbers and determined that it was a 68-69 with a 4 cylinder D339 and a powershift transmission part number 2S7900. That is all I have to go on.
The 48a is D7E with d339 and the D7F is 6 cylinder 3306 motor
D7 I do not know about the number, but it has a 4 cylinder in it.
Your machine serial number is 48A12562. That is a D7E and a fairly late one with a D339 high horsepower at 180 hp. The last one was around serial number 48A13718 or thereabouts. I think the D7F replaced them in 1970, which was a 6 cylinder machine. The 48A means that it was equipped with powershift transmission from the factory. The equivalent of it in a military tractor is a 75E serial number. Your worry about an early and late powershift transmission was with the D7F, not the D7E. Hector, the first D7F's had D333C's in them which later became the 3306. The higher revving 6 cylinder caused problems with the same transmissions they used from the slower revving D7E in the first D7F's. They changed that transmission to the smaller D6C transmission at about serial number 94N5192 and cured the problem. The 47A was a direct drive D7E.
I've had a couple of D7E's and been around several more. They are very good machines. But they are 40+ years old and could be worn into a complete pile of junk. If you find one in the right stage in its life it will make a good machine for you.
I always felt the Cat D7E series was a well built reliable classic machine . If it's the later high horse model that would be even better . Just about the perfect size dozer for most work . Big enough to move some dirt & take out trees and such . And yet not to heavy for muddy conditions & soft ground , and moving from job to job . Parts are still available . Depends on the condition of the machine your looking at and price they are asking for it . On Machinery Trader it's pretty common to see a well maintained 7E in the 25 to 35 thousand range. They seem to hold there value good .
have a D7e series E 48A1547 piston went through block wonder what best route would b to repower rest of machine great shape
Plenty of OEM or aftermarket parts available still. Get hold of a block and go from there..?
If it is a E you are good if its a F run away from it the Fs were plagued with trans problems they went from a to a 6 cyl. but kept the same trans and it would not hold up
Would you be interested in a package of D7e's? Both run very good. One has a newer trans. One is complete but broke a tooth in left final. The other is really nice. New seat, guards, and a newer trans., all steering pins and more. We pulled it apart to do some final seals and we see it needs dead shafts. so it is on blocks. I'm thinking i might sell both. Both have very nice undercarriages. They would come with 4 blades. 2 straight with tilt, 1 twin tilt angle blade and a rake. Might be more than you are looking for. In upper Michigan. Phone text/call is best 906-395-7015 if anyone is interested
I did a trans rebuild on a 7F, this is enlightening... I knew at the time they were a weak spot, but this explains a lot!
I wonder why though. The torque on the transmission would be less at higher rpm's. Was it lubrication problems, at higher speeds the transmission could not get adequate lubrication to all the bearings and gears now running much faster? Was it shifting stress? People shifting the transmission speeds and directions at now much higher engine RPM's then the maximum 1200rpm in the D7E?
Torque converter?
Higher engine speed equals higher shock load when shifting to change directions. Among other things.
I heard that the much higher engine speeds of the 7F's was the culprit. To solve the problem I heard they actually put the D6C or D transmission in the 7F in later models & the problem was solved. Anyone else hear that?
From an old post....