Help finding Input Shaft Bearing for 3 speed

[dznucks]

I have a three speed transmission that I believe is a Muncie. I just replaced my clutch assembly, pilot bushing, and input shaft bearing. I took the old input shaft bearing to a reputable, local tranny shop to ensure that I got the right bearing. They gave me a N307LOE bearing. I noticed the bearing was just a bit shorter (~.040") than the original and the guy at the shop told me that wouldn't make any difference.

Now the tranny has been popping out of third gear and i can feel some play in the transmission while driving. I am assuming that this .040" width difference is causing the problem.

The original bearing has the following dimensions.....ID 1.378" (35mm), OD 3.152" (80mm), and a width of .709" (18mm). The new bearing has the same ID and OD, but the width is .669".

Can someone tell me how to find the correct bearing?

[68gmsee]

Look for a bearing shop or store in your area.

I had a similar problem with a bearing years ago and a mechanic told me to go to a local bearing shop. They got the number and measurements off the original and matched it perfectly.

Hopefully you kept the original bearing so a bearing shop can get the number off of it and get the right one for you.

[dznucks]

I actaully have a spare tranny thats identical, so i have two of these bearing made by different manufacturers and with different part numbers.

I'll give that a try.

thanks

[dznucks]

The stampings on the transmission are M5P05A. Based on what i have read online about decoding this, I have a Muncie M20 out of a '65 vehicle.

Can someone confirm this?

[dznucks]

I think i have made out the bearing numbers.

Can someone cross reference a New Departure Bearing? NDH 43307AD

[LandonL]

I have one for a Muncie SM318 that I didn't use, two actually. Is yours a SM318, 3spd? I have a picture of mine.





You may also find it at rockauto, I just check and they have one. Not sure of dimensions.

You sure the shifting rod to the gear selector isn't loose?

[dznucks]

No, my transmission doesnt look exactly like that. The main body is a little longer, but the tail shaft is smooth like yours, no bosses or tranny mount locations.

I have shifted the transmission by hand, from underneath, and it shifts smooth and solid. I'm pretty sure the problem is the bearing.

[LandonL]

Ah well, best of luck to you!

[Zeke]

I did a search and there is a Timken company in Smyrna, 3300 Highlands Pkwy SE Ste 295 · Smyrna.

I have replace lots of bearings in parts that only came as assemblies at parts stores. Can't beat $5 for a bearing vs $40 for the whole part.

As said before take your old bearing if you have it or the part number and they can match it up. Also was there a shim in the front housing? Many times a shim is used to get the end play right.

Also check the detent cam in the side cover, might be worn or spring weak.

[dznucks]

I am going to try Applied, down south of the airport. I have heard they can match any bearing.

There was not a shim in either of the transmissions. i thought about finding a metric washer or something to shim the play between the bearing and the small c-clip. But that wont help the play between the inner side of the bearing and the input shaft. The larger C-clip keeps the bearing from going into the transmission. Since this new bearing is .040" shorter in that dimension, theres .040" play inside of the tranny.

[dznucks]

I did find this on a buick forum. I may give 5speeds.com a call.


http://70.86.163.37/showthread.php?p=1570558

[raycow]

If you have the HD Muncie 3 speed, the GM designation for that is SM330. It has a 7 bolt side cover and is often confused with the much more common Saginaw (SM326) which it superficially resembles. As you have found out for yourself, its parts do NOT interchange with the Saginaw.

The .040" shim between the thinner bearing and the gear should be a workable fix, but I am surprised that your bearing house can't interchange the NDH number.

Ray

[dznucks]

I actaully have two of the Muncie's and a Saginaw in the shop.

The two muncies were built several years apart and use the exact same bearing. That's why I find it hard to believe its not easier to find the right bearing for this tranny.

[dwcsr]

Try rockauto.com
https://www.rockauto.com/dbphp/x,car...6_Bearing.html

[dznucks]

Thanks dwcsr. those are the only bearings i am finding and they aren't the right ones.

I spoke to Applied Technologies (Atl Bearing shop) today and they said the bearing i am looking for is obsolete. The only thing that I can do is shim the N307LOE bearing that I have in it now.

Surely I am not the first person to run into this issue.

[LandonL]

Did you get rid of the old one?

[dznucks]

Did you get rid of the old one?

no, i have both the old ones. i am starting to think that replacing the bearing was a waste of time and money. I just thought i would replace it while i had it out.....the tranny came from a board member and i wasnt positive of the bearing condition.

I may put the best bearing back in or use some shims (arbor shims) to shim the new bearing back out.

[LandonL]

I would vote put the best one back in, and if you still have the problem, you'll know it's not necessarily the shaft bearing and you can debug from there.

[vectorit]

Hit up these guys.

http://www.anaheimgear.com/

They had parts for my stuff.

[dznucks]

Hit up these guys.

http://www.anaheimgear.com/

I sent them an email. Pat, at Anaheim, knows about this bearing and he has a source for replacement bearing. He didnt share the source or part number. He wants $40 each, but the shipping to the opposite coast is going to make it cheaper to go with the new N307LOE I already have and use arbor shims to shim the extra gap.

I have ordered some .020" arbor shims from grainger. I am going to try to use two of these arbor shims to take up most of the .042" gap.

http://www.grainger.com/Grainger/Arbor-Shim-5GB24