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Discussion Starter · #1 ·
Looking for some advice. Trying to replace the input bearing on an M21. Removed the cover and nut and tried to pry outward on opposite sides of the snap ring. Outer race is loose from the case but tight on the shaft. Put pressure prying out and tapped the shaft inward with dead blow hammer. Maybe got a 16th or an inch or less. The bearing is way too tight on the shaft. Trans is in great shape, maybe 1000 miles on the trans.

Talked with several people and they never had one that did not come off with some prying pressure and tapping. One recommended heat on the shat but that seems excessive and might weaken the metal.

Do not really want to pull the whole assembly out the back just for the front bearing - would still have to get it off anyway.

Any ideas?

Mike
 

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Posi-loc makes a puller that will grip the snap ring groove if you can find one -tool rental place ?
Cost $150(?) 10 years ago but works great !
 

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Discussion Starter · #5 ·
Thanks - A friend has a brass block for me to try. Was a little afraid of breaking that snap ring with all the pressure and banging but will try that.

On the 1000 miles - I got the trans from a friend - swapped my M20 for theM21. He said it was a fresh rebuild. Last year I noticed a noise when I had the trans in neutral and the clutch out. You could tell it was a soft rotating noise - right under the shifter. Clutch in and sound goes away. So its not the TO bearing. I have had two TO bearings the last couple of years cause I had the motor out and just changed it while apart.

The idea was to pull out the input bearing to see if it bad. Replace anyway with it out - then I will know. Took side cover off and insides look great - no syncro wear and gears all look good.

Mike
 

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How about renting a two piece knife edge bearing puller from O'rielly or Autozone? There is normaly no charge,they just take your credit card info and if the tool comes back OK $0.Even if you can't get the puller edge behind the bearing it should be able to get a bite in the snap ring groove of the bearing.My Snap-On puller has a threaded hole in each half of it,you should be able to rig something up with threaded rod and a crossbar on the upper end of the shaft. I'd be more concerned about doing some internal damage to the trans if the new front bearing is tight going back on.A lot easier to install the bearing when the input shaft is out,either way make sure when installing it you don't tap the outer race,use the inner. I'm not an expert on Muncie 4 speeds, but I sure got a lot of good tips from Paul's book on Muncies from 5 speeds.com
 

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Discussion Starter · #7 ·
Puller is a good idea. We found an old puller in the tool box - 3 finger but was about 2 inches too short to the front of the shaft. Your idea would work - will try that if the tapping with a hammer doesn't work.

I did talk to Paul on the phone at 5speed. Have his DVD. You are right about easier if the shafts are out.

Note - I am doing this with my 81 year old Father (retired Chevy mechanic). Bonding thing. He is Sooooo upset that it would not come off. Said he has done a hundred of these and never had one that tight. Was nice to see him get 'interested'.

Got a great story from him on the early 50's automatic trans with cones instead of clutch plates - pre-powerglide days. Cool stuff.

Thanks for the ideas so far....

Mike
 

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Usually a noisy neutral rotating noise is a worn input shaft gear and the countergear drive teeth. These two gears are also referred to as the headset.

To confirm if your headset gears are worn, your transmission will be quiet while cruising in 4th gear. Changing the front bearing will not help with your neutral whirring noise if the headset is worn.
 

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I have used snap rings stacked one behind another and tap the input shaft like above, good luck!
 

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I have used snap rings stacked one behind another and tap the input shaft like above, good luck!
I'm surprised no one has mentioned this method yet!!!!!!!!!!!!!!!!!!
This is the EASIEST trick, and it works!!!!! :thumbsup:
 
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I'm surprised no one has mentioned this method yet!!!!!!!!!!!!!!!!!!
This is the EASIEST trick, and it works!!!!! :thumbsup:
Sometimes people don't have a stack of 308 snap rings lying around. ( the 308's fit over the bearing nicely.)

I sent him a bunch of rings...
 

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