I just picked up a nice pair of D3 chains, they are 6 1/4 inch pitch, will they work on a D4D,D4C or what is the differance? They are 36 pad the same as mine. thanks for any help you can give.

The D2/D3 is 6.12 in. pitch.
The D4 is 6.75

Thanks Old Magnet for the fast reply, my wife bought these chains at an auction saturday I could"nt be there. I got them home today and after closer measuring they are 6.125 pitch and the Cat number is 6S8344X. The rails are good shape and the bushings have not been turned. I could not measure the rails on my D4D as it is still in Ohio and I have not been able to spare the time to go get it yet. If anyone needs this pair of chains I might be able to deliver them closer.

I'm with Old Magnet in thinking the D3 rails are the same as the D2 at 6.125 inches (6 1/8"). You might want to remeasure your link distances

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Could be you have some slack in the pins and bushings??? Best to measure distance between center of 5 pins----divide by 4 for number of links involved.

The IH TD-8 (I am thinking) ran a link real close to the D2 and D3 (I believe it was 6 1/4")----but not quite the same. We had a discussion on the old bulletin board covering that some time ago----will see what I can find on it.

There have been some people use the D3 rails on the D2s (with no mention of changing sprockets)

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and use the D3 bottom rollers by installing a filler bar to make up for the smaller diameter D3 roller size.

Delta Dirt

I stand to be corrected

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Looked back over to the ACME site and pulled up the thread referencing the IH rails. The IH rails that I was thinking of actually measured 6" (going the other way )

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and fits the IH TD-7 and TD-8.

I had picked a set of these up from a neighbor selling them for scrap a couple of years ago

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they actually came off of a IH 1460 combine (I-Trac brand---made in Itlay).

Hopefully

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someone else can help clarify what you've got. Still might want to remeasure----if they definitely came off of a Caterpillar.

Delta Dirt

D4D83J - Your 6S8344X link is the LH link of the 6S8343/6S8344 RH/LH pair that make up a D3 track chain.
These are the later style D3 chains, that use a 9/16" track shoe bolt, as compared to the earlier D3 link that used a 1/2" pad bolt.

The new rail height on these links is 3.31", and 100% worn is 3.00" height.
You'd need to stretch the chain out tight, and measure internal wear to get an accurate idea of condition.
Bushings that look good externally, can have serious internal wear, that means either a turn is now due .. or even worse .. overdue.
Measurement over 4 links (5 pins) is 24.54" new .. 100% worn is 25.02".

The links are indeed 6.125" pitch, and they will not fit your D4 .. however they will be attractive to someone with a D3 or a D2 that needs an undercarriage rebuild.
The D3 undercarriage can be adapted to the D2 with a modest amount of work, mainly on fabricating and installing spacers for track rollers.

Thanks Oz. Sounds like great information, cuts right to the chase does"nt it. The reason I came up with the 6-1/4 measurement was because it was dark and I was trying to hold the flashlight and the tape at the same time. In the daylight they measured 6 1/8, I think I"ll go with the daylight figure. It will take a few days to take some more measurements. Maybe I can make someone a good deal on these for a D2 or D3.

This is the secret here.

You'd need to stretch the chain out tight, and measure internal wear to get an accurate idea of condition

How you plan on doing this with them off the tractor?

Kelly

Oh by the way, that guy that lives just east and north of State Hi-way yard that has the big metal building for shop… is a old friend of mine…do you know him? I live in G Junction.

With reference to using the D3 rails on a D2, a Cat engineer who collects antique Cats recently told me that if the D2 sprocket is worn, you can "get by" with D3 rails, even though they are higher than the D2 rails are. I just pass this on, but I have no personal experience with trying D3 rails on a D2.

Are you guys from Colorado going to Fred Lowery's?

GWH

GWH,
I will be there, I have already called Ken. I don’t know about D4D83J.

I am going to bring Ron R., one of H-E Lowdermilk’s lowboy drivers as well. Ronny has a story to tell Fred about one of the trucks Fred bought at there sale….the one the D9G track rolled…it took me about 10 years to get the whole story on that deal, but Ron knows it all…..it was his truck. Fred has heard the story but not first hand. We’ll see you there.
Kelly