My understanding is they interchange, I've just fitted D4D bottom rollers to my old RD4 without any drama's.
Mike
All the D4's and RD-4's use 6.75" pitch track links, from the very start of RD-4 production. However, there are at least 6 different track link P/No's.
Basically, the variations between the 6 different links, are in track link height and wear limits, and in track shoe bolt diameter.
With each progressively-improved track link, the link height increased, the hardening depth increased, and the bolt diameter increased.
In order of P/No sequence, the links P/No's and specifications are;
P/No .......... Height ...... Bolt Dia. ..... Hardening depth to Rc 45 ...... Replacement height limit
6B4645 ...... 3.53" .......... 1/2" ...................... .000" ................................. 3.15"
4K7039 ...... 3.66" .......... 1/2" ...................... .130" ................................. 3.25"
4K6647 ...... 3.66" ......... 9/16" ..................... .130" ................................. 3.25"
5K9423 ...... 3.66" .......... 1/2" ...................... .260" ................................. 3.25"
5K9457 ...... 3.66" ......... 9/16" ..................... .260" ................................. 3.25"
7K1825 ...... 3.75" ......... 9/16" ..................... .260" ................................. 3.40"
Information is from the CTS handbook dated January 1970.
Note: the link P/No's are consecutive for RH and LH links.
Our channel highlights machines from the earliest Holt and Best track-type tractors, equipment from the start of Caterpillar in 1925, up to units built in the mid-1960s.
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