D2 U series & J series compatiability

[mcarp]

OK this might be a stupid question but thats never stoped me before. If you have acouple D2's that are the same year what are the main differences between the 3j,5j,4u&5u.I know there are many in the engine and pony motor but what about the undercarrige ,the rollers, sprocket, chains ? or the final drive, steering gears,brake drums. are there parts you can swap from one to the other to make it work? I know I think too much.

[oldparker]

The 3J and 4U tractors are the 40" narrow gauge or (standard) gauge tractors and the 5J and 5U are the 50" wide gauge tractors. Very few parts interchange between the "J" series and the "U" series. Most everything will interchange between the narrow and the wide "J" tractors with the exception of some of the undercarriage and final drive parts. Same for the "U" series narrow and wide. It is necessary to have both "U" and "J" series parts books to compare parts and their numbers to determine interchangeability.

[B4D2]

No such thing as stupid questions, but there certainly can be some ridiculous answers. First off, you will never be able to "...have acouple D2's that are the same year what are the main differences between the 3j,5j,4u&5u." 3J and 5J D2's are basically the same machine mechanically with different track spacing (Gauge). They are identical as far as motor and tranmissions are concerned. 3J is a 40" gauge and 5J is a 50" gauge. Both use the D3400 motor. The 4U and 5U are identical again as far as motor and transmission, and again, the only difference is the gauge (again 40" or 50") They use the D311 motor. There is a difference between the early 4U and 5U's VS the "late model" D2s in that the transmission was stretched to allow for a split coupling that facilitates clutch changes without splitting the tractor. There were also sheet metal modification to accomodate the stretched machine. Several parts from late model U's to early model U's will interchange, several will not. You really need to specify what parts you would like to cross reference. The D3400 and the D311 are two completely different motors. You should purchase parts books for the machines you own, whether they be a J or a U model.

[mcarp]

Thank you oldparker and B4D2 the info helped me get my mind right for awhile anyway.

[Rd6 plower]

Hello there, My dad and me have a couple of D2's as well u and j series. A "39" "45" j series and 2 "52" u's one with a 2s cat blade set up , my favorite and one tail seat. Well back to the subject I know the bell housings are the same, the pony blocks not only on the D2's but also the same on the D4's t's j's and u's and finally the pony clutch is the same for the d2 d4 and d6 up to the u series. That's pretty much all other details I can offer.

[Billy-]

You will find that the transmissions, brakes, finals and steering clutch between the 3J and 5J will mostly interchange between early 4U and 5U series.

[mcarp]

cool ,thanks rd6 that will come in handy for the pony that does need some help. do you happen to have the piston size on the D3400 & D311?

[mcarp]

thanks Billy, the D2 Im working on is a 5U 2642 ser.no. year 1949 would say that an early one by the number but not sure. The one im going to look at tomorrow all I know is its a D2 , the guy said it was made in 1949 but didnt have the ser. no. so not sure. Basicly just getting some info so I tell if its worth getting for parts.Ive priced some stuff at the bone yards and there very proud of what they have to offer. do you know where the ser. no. changes are?

[Billy-]

A early D2 4U or 5U is one before serial 4U6373 and 5U13237. After those serials the D2 had a major redesign.

What changes do you want to know?

Cheers
Billy

[ccjersey]

cool ,thanks rd6 that will come in handy for the pony that does need some help. do you happen to have the piston size on the D3400 & D311?

They are different if that's what you mean.
D3400 is 3 3/4" bore
D311 is 4" bore.