Author Topic: Countershaft Disassembly  (Read 2723 times)

dwhite

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Countershaft Disassembly
« on: February 27, 2016, 09:57:49 AM »
I'm working on my transmission and I need to pull the countershaft drive gear off of the countershaft.  According to the figure (pg 135 in TM 9-170A) in the TM they use a heavy duty (huge) two-jaw gear puller.  I did a quick look on the internet, but couldn't find anything that looked similar to the puller in the TM.  Has anyone successfully used another method to disassemble the countershaft drive gear?  Dale
MVPA 17456
1952 M37
1970 M35A2C
1943 Diamond-T M3A1 under restoration

yd328

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Re: Countershaft Disassembly
« Reply #1 on: February 27, 2016, 04:37:30 PM »
 I've only seen that type of puller in a slide hammer set as a axle puller. I'm going to take my gear set to work and see what the truck guys have for pullers. I have a bolt grip puller set but it will only take up to a 3/8" bolt. 

Gary

yd328

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Re: Countershaft Disassembly
« Reply #2 on: March 04, 2016, 06:16:48 PM »
Here is a puller that I used to get the gear off. It is a OTC 10 ton push/puller. I would say get the 17ton if you have that option. It was a fight most of the way off.  Since that gear was chipped already and I was operating alone I used a bfh, gave it some love taps to move it along. Every half turn of the wrench required some hits to move it.

Gary

dwhite

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Re: Countershaft Disassembly
« Reply #3 on: March 05, 2016, 04:20:25 PM »
I made a jig that's bolted on to the drive gear and put the whole assembly on a 20-ton press.  No luck; drive gear won't budge.  Evidently they must have used a heavy press fit.  The main problem I have is that at one time the gears were not seated properly and there isn't quite enough room for the retaining ring to fit in at the end of the shaft.  Considering the heavy press fit, I'm wondering if the retaining ring actually serves any purpose.  If it's not needed, I think I leave it off and put the countershaft assembly back in the transmission.  Thoughts?

Dale
MVPA 17456
1952 M37
1970 M35A2C
1943 Diamond-T M3A1 under restoration

yd328

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Re: Countershaft Disassembly
« Reply #4 on: March 06, 2016, 07:30:33 AM »
My gear was damaged and the shaft is pitted where it rides in the bearing so both are getting replaced. The TM says to finish with a press once you separate the gear enough to get a fixture behind the gear.
I agree that ring probably doesn't do much as far as retention of the gear set, mine was on tight too(snap ring). I think that ring probably helps hold the washer that goes between the gear and bearing centered in place. I'll look at it closer today.

Gary

yd328

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Re: Countershaft Disassembly
« Reply #5 on: March 06, 2016, 12:25:51 PM »
Quote
I think that ring probably helps hold the washer that goes between the gear and bearing centered in place. I'll look at it closer today.
Forget that, I found the washer that was in there is the wrong one. So the snap ring does not support the bearing washer as I thought. Heres a picture.


I put mine back together with a new shaft and gear. It went together much easier than coming apart. I did put the countershaft in the freezer for a couple of days. I'm not sure how helpful that was, but it went together a lot easier.  So, if I did end up with a burr between the gears or had to reseat them, I would take them back apart to correct it so you can put the snap ring in. Hope this isn't confusing and helps.

Gary

dwhite

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Re: Countershaft Disassembly
« Reply #6 on: March 06, 2016, 04:19:55 PM »
Thanks for the follow up.  I did manage to find a tru-arc heavy duty snap ring that was about 0.015 thinner than the original retaining ring, which just barely fit in the groove.  At this point I think I'll recheck the clearances and if I don't run into problems I'll go with what I have.  After trying to get the drive gear off with a 20-ton press, I'm uneasy that I'll tear something up.  Cooling shafts in the freezer always helps when assembling interference fits.

Dale
MVPA 17456
1952 M37
1970 M35A2C
1943 Diamond-T M3A1 under restoration

Smadge

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Re: Countershaft Disassembly
« Reply #7 on: January 09, 2019, 06:58:36 PM »
If all the gears look good is there a reason to take the countershaft apart during a rebuild?
1941 M2A1 Autocar (restoring)
MVPA# 36810E

yd328

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Re: Countershaft Disassembly
« Reply #8 on: January 10, 2019, 08:07:29 AM »
As long as the gears are good you should be ok as long as there is no other damage to the shaft. I only pulled mine due to chipped teeth on that gear.

Gary

Smadge

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Re: Countershaft Disassembly
« Reply #9 on: January 10, 2019, 09:19:34 AM »
Thanks Gary!
1941 M2A1 Autocar (restoring)
MVPA# 36810E