[spb350]

I bought this M20 from a guy I knew pretty good and he said it was a fresh rebuild, so I popped the cover off and it looked real good from what I could see. Installed it and I have driven about 200 miles and it was shifting good but was making a noise when the clutch pedal was out and the tranny in nuetral, clutch in no noise. So I pulled it out today and pulled the input bearing retainer off, here are some pics. Obviously there is some problems. The drain plug was not real bad but the other magnet in the bottom looks heavier (no chunks). Something is way off or was run for a while before I got it. About 1/3 of the shaft appears to be crumbling

What causes this issue?

Is the input shaft toast?

What parts would it be wise to replace?

How do the gears and syncros look?

Is the Input Bearing Retainer shot?

Thanks

[spb350]

pics of the patient

[Sun Tuned]

Input bearing retainer is toast.
Pic 4 at bottom left corner looks not good.
Clutch pedal out and in neutral sound.... Is it real steady knocking noise?

Last one I worked on that did that had a chipped tooth (actually a missing tooth) on the cluster gear.

Look it over very closely.

[spb350]

a few more

[spb350]

Originally Posted by Sun Tuned

Input bearing retainer is toast.
Pic 4 at bottom left corner looks not good.
Clutch pedal out and in neutral sound.... Is it real steady knocking noise?

Last one I worked on that did that had a chipped tooth (actually a missing tooth) on the cluster gear.

Look it over very closely.

There is no knocking sound at all and it was shifting very good when cold and a little tougher when hot, its more like a bearing going bad, a growling noise.

[pfilean]

With the clutch pedal out and in neutral everything inside is turning except the output shaft and maybe some of the reverse stuff. So probably either the input shaft bearing or the cluster gear needles or both. That input area makes me wonder if at some time someone blew a clutch plate and scattered stuff around but never cleaned out the debris when the clutch was replaced. Take it apart and clean it up and see what you need to buy.

[spb350]

I pulled out the bearing today and the back of the bearing has wear marks. Are these caused by the shim/spacer spinning?

[chrisp]

It appears that the front bearing nut was not properly adjusted & caused all of the damage / wear.

[spb350]

Originally Posted by chrisp

It appears that the front bearing nut was not properly adjusted & caused all of the damage / wear.

Was it too loose or to tight?. Getting it off was not difficult but it was not real loose either. I don't want it to happen again whats the best way to properly adjust it? Thanks

[spb350]

I got the new bearing today and it is quite a bit thicker then the old one. It is going to sit in the case 1/8 of an inch deeper and will be hitting the main input gear I think? There is supposed to be a space between the gear, the bearing and the slinger right?

[Lemans64]

Should be able to get the old bearing the same size, new bearing is probably sealed?? I made a shim on mine so I could use the sealed bearing. Some places sell shims for this application, just can't remember where. I made mine out a piece of aluminum. 4mm is the size I believe, .160" ?? mine went between the snap ring and case to space the bearing out far enough so not to hit gears.

[spb350]

Originally Posted by Lemans64

Should be able to get the old bearing the same size, new bearing is probably sealed?? I made a shim on mine so I could use the sealed bearing. Some places sell shims for this application, just can't remember where. I made mine out a piece of aluminum. 4mm is the size I believe, .160" ?? mine went between the snap ring and case to space the bearing out far enough so not to hit gears.

Did you make a new thicker gasket for the retainer? I'm thinking I just need a thinner bearing.

[Lemans64]

No I used 2 gaskets, one on each side of aluminum shim. Can send pictures if wanted, but not till sunday as work gets in the way tomorrow and will have to drag spare trans out to get pics. Yup did it to 2 transmission. m20 in car and 21 spare. Have old bearing number if wanted. Should be able to get non sealed old bearing if wanted.

[spb350]

Originally Posted by Lemans64

No I used 2 gaskets, one on each side of aluminum shim. Can send pictures if wanted, but not till sunday as work gets in the way tomorrow and will have to drag spare trans out to get pics. Yup did it to 2 transmission. m20 in car and 21 spare. Have old bearing number if wanted. Should be able to get non sealed old bearing if wanted.

Thanks for the offer but I think it will just be easier to get a correct size.

[Lemans64]

found the listing. http://www.thegearbox.org/catalog/it...82/4902873.htm

[spb350]

Does anybody sell a heavy duty thin bearing?

[spb350]

I called the Gear Box and have the above bearing kit coming. The heavy duty bearing just seems like the way to go.