Ironhead ‘72 IH…early or late ‘72?

[NP72Iron]

Hey all,
Working on building up the tranny on my ‘72 XLCH and when looking for the countershaft low gear bushing, the parts catalog lists 2, one for 54-early 72 and one for late 72 on.
How do I know if mine is an early or late 72 model?
#42 in the photo.


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[bustert]

both have the same id
the diff is in length
35787-52 is 5/8
35787-72 is 1/2

[NP72Iron]

Thanks for your reply [mention]bustert [/mention]. I don’t have one to measure for my current motor, so I don’t know which length I need.


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[needspeed]

In another thread you say that you don't have a c shaft 1st gear and don't know if it should have a speedometer gear attached to it.

Does your '72 right side countershaft boss look like the pics in post 1 here:
http://xlforum.net/forums/showpost.p...70&postcount=1

Or the pics at post 6 here? (probably not)
http://xlforum.net/forums/showthread.php?t=1257259

Chances are better than good that your '72 came with the trans driven speedo gear. If your case looks like the early one, then it did, and you have a choice. You can run the gear with the attached speedo drive or run a later gear without the speedo drive gear and no speedometer.

As to the bushings. Early gear use 35787-52. Late gear use 35787-72

[rocketnorton]

i have a 1cs gear w/speedo gear, if ya want/need
cant see where you are
it's new a/m

im not using speedo drive in mine
if youre not gonna either, id suggest a reinforcing ring on cs bearing boss

also have used drive and new cable

[NP72Iron]

Originally Posted by needspeed

In another thread you say that you don't have a c shaft 1st gear and don't know if it should have a speedometer gear attached to it.

Does your '72 right side countershaft boss look like the pics in post 1 here:
http://xlforum.net/forums/showpost.p...70&postcount=1

Or the pics at post 6 here? (probably not)
http://xlforum.net/forums/showthread.php?t=1257259

Chances are better than good that your '72 came with the trans driven speedo gear. If your case looks like the early one, then it did, and you have a choice. You can run the gear with the attached speedo drive or run a later gear without the speedo drive gear and no speedometer.

As to the bushings. Early gear use 35787-52. Late gear use 35787-72

Looks to be the second one, right?


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[brucstoudt]

nope.the early one with a reinforcing ring rocketnorton mentioned.kind of looks like the r/s case broke before the ring was installed?

[needspeed]

Well you sure can learn alot from a picture. And now you know what gear you need. Brucstoudt is right. Your case came with a speedometer drive gear and the boss that holds the bearing cracked and has been repaired.

This means you can't use the speedo drive gear. You need the later C shaft 1st gear #35760-73. It should come with the bushing installed.

The OEM mainshaft bearing race has been replaced. That's not a bad thing. Just saying.

[NP72Iron]

Thanks for all the replies guys. You all are what makes this forum so great!


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[DR DICK]

see #45 in your pic.
on the gear there is a recess that washer fits into.


depth of that recess is appx 1/16" for the early gear. uses the -52 bush. uses one of #45 washer.



depth of recess is appx 1/8" for late gear. uses the -72 bush. if you have this gear you use two #45 washer stacked up.