Author Topic: Questions about Muncie parts and casting number question  (Read 367 times)

Bryan302

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Questions about Muncie parts and casting number question
« on: June 20, 2016, 04:10:47 AM »
I'm in the process of gathering parts to build a 1968 3925660 M20 for an upcoming project.  I would like to replace the plastic speedo gear and retainer clip (as other members have done, talked about in other threads) with the steel 8 tooth gear as used in the 1967 010 trans.  Would I be correct with the 8T steel gear, part #3708145 to replace the plastic gear?  I also understand that 6261794 and 3924097 are replacement numbers for the same part, are these numbers correct also?  I will be using the black 23T driven gear, 3860346, for 3.73.

Are the main shafts the same between 67, (intended for the steel gear), and the 68-69 main shaft intended for the plastic gear.  Is this a direct conversion?  My main concern is that the steel gear will end up in the right spot to mesh with the driven gear, being that it doesn't have the spring clip to hold the gear in the right spot.

Since the 1968 3925660 case uses the 3884685 side cover, Does the 1968 3925660 also use the 3851326 front bearing retainer, or the 3915020?  Which front bearing retainer is correct for 1968?

Thanks,
Bryan
Bryan S.
1968 RS Z/28, 12E, PNT R2, TR 749
1969 Z/28 X33, 05A, PNT 52 52, TR 719, endura bumper

ko-lek-tor

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Re: Questions about Muncie parts and casting number question
« Reply #1 on: June 20, 2016, 11:14:03 AM »
James to strangers, Bentley to friends
1969 SS/RS 396 coupe Hugger Orange X22 712 bought in 79
1969 SS 350 coupe LeMans Blue 713 bought in 79
1969 307 4spd. coupe Daytona Yellow 711 bought in 85

Bryan302

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Re: Questions about Muncie parts and casting number question
« Reply #2 on: June 26, 2016, 04:04:19 AM »
thanks ko-lek-tor.

so, several members were saying in other threads that they would recommend changing the plastic gear because of the spring clip breaking.  I really didn't want to spend up to $120.00 for the NOS steel gear until I had a good idea of which one was best to replace the plastic gear.  I've heard of at least three different part numbers for an 8T gear.

Since this steel gear was last used in 1967 and pressed on, and the spring clip held the plastic gear in place in 1968-9.  What lines the steel gear up with the driven gear since it does not have the spring clip to locate it on the shaft?  Anyone?
Bryan S.
1968 RS Z/28, 12E, PNT R2, TR 749
1969 Z/28 X33, 05A, PNT 52 52, TR 719, endura bumper