Should I replace this input shaft bearing?

[flagoworld]

On this getrag 240, is this enough play that I should replace the input shaft bearing or will the pilot bearing hold it steady enough?

 

 

Edited February 25, 2021 by flagoworld

[Son of Marty]

If it is smooth when you rotate it I would run it, remember the end of the shaft your holding is supported by the pilot bearing and it won't be able to move like that at all.

[flagoworld]

Just now, Son of Marty said:

If it is smooth when you rotate it I would run it, remember the end of the shaft your holding is supported by the pilot bearing and it won't be able to move like that at all.

 

Thanks, that's what I was thinking too. Seems to be buttery smooth in all gears...

 

And... Leak free ? .. My 4 speed leaks like a sieve. Hopefully in the next few months I can get this thing installed.

[Einspritz]

Here's the deal; that shaft has a lot of play from what I can see. It might be best to measure it to be sure. It rides in the front bearing AND it has another roller bearing that is internal which holds the gear shaft. There are shims between that and the guide sleeve for 4th gear.

 

So, while the shaft may be supported by the pilot bearing, the play at the other end may or may not affect those shims.

 

In my last transmission I rebuilt (100K miles), it did, and tore those up, which I found fragments in my fluid and damaged 4th gear to the extent that I had to use my "NOS secret stash only use in emergency mega buks I don't know when or where I acquired them" spare gear set. After confirming with a borescope.

 

BTW, it too, shifted "Buttery Smooth" and wasn't noisy.

 

In the end, make a jig and measure it. IIRC the end play should be in the Blue Manual.

 

the good news is that you already have it out of the car.

[flagoworld]

45 minutes ago, Einspritz said:

Here's the deal; that shaft has a lot of play from what I can see. It might be best to measure it to be sure. It rides in the front bearing AND it has another roller bearing that is internal which holds the gear shaft. There are shims between that and the guide sleeve for 4th gear.

 

So, while the shaft may be supported by the pilot bearing, the play at the other end may or may not affect those shims.

 

In my last transmission I rebuilt (100K miles), it did, and tore those up, which I found fragments in my fluid and damaged 4th gear to the extent that I had to use my "NOS secret stash only use in emergency mega buks I don't know when or where I acquired them" spare gear set. After confirming with a borescope.

 

BTW, it too, shifted "Buttery Smooth" and wasn't noisy.

 

In the end, make a jig and measure it. IIRC the end play should be in the Blue Manual.

 

the good news is that you already have it out of the car.

 

Tell me more... The play is something like 3mm at the end of of the shaft as you can see. I thought it seemed like a lot too. But I want to know more about the exact procedure for measuring and fixing, etc.

[TobyB]

Nah, that's pretty good.

 

I mean, yes, of course the 'service maxiumum' is 1.8mm, you MUST replace zer bearing

at twice ze cost of whole E46.

 

If you want to convince yourself, measure how far it travels in- plane (in- out).

 

Bet you a broken license plate light bezel it's well less than a mm.

And less then a few tenths radially.

 

That shaft can float a LOT before it does any damage.

 

Sadly, the countershaft bearing that meshes to the input shaft is the

weasel in the henhouse- and there's no way to measure what it's up to.

I mean, you could bore a couple of holes in the case, preload it, and 

then take measurements under load.

 

But seriously.

 

It's a 4 speed.  It shifts.  Has a 2nd gear synchro?  Doesn't leak.  Stays in gear.

Is quiet?

 

RUN IT!

 

t

the diff weighs more than the 4- speed.

[flagoworld]

19 minutes ago, TobyB said:

Nah, that's pretty good.

 

I mean, yes, of course the 'service maxiumum' is 1.8mm, you MUST replace zer bearing

at twice ze cost of whole E46.

 

If you want to convince yourself, measure how far it travels in- plane (in- out).

 

Bet you a broken license plate light bezel it's well less than a mm.

And less then a few tenths radially.

 

That shaft can float a LOT before it does any damage.

 

Sadly, the countershaft bearing that meshes to the input shaft is the

weasel in the henhouse- and there's no way to measure what it's up to.

I mean, you could bore a couple of holes in the case, preload it, and 

then take measurements under load.

 

But seriously.

 

It's a 4 speed.  It shifts.  Has a 2nd gear synchro?  Doesn't leak.  Stays in gear.

Is quiet?

 

RUN IT!

 

t

the diff weighs more than the 4- speed.

 

It’s a 5 speed though

[Mike G]

54 minutes ago, flagoworld said:

 

It’s a 5 speed though

only until the 2nd gear synchro goes out

[TobyB]

240, 242, whatever it takes!

 

I'd not worry.

 

 

t

won't live that long 

[flagoworld]

On 2/25/2021 at 4:22 PM, Einspritz said:

Here's the deal; that shaft has a lot of play from what I can see. It might be best to measure it to be sure. It rides in the front bearing AND it has another roller bearing that is internal which holds the gear shaft. There are shims between that and the guide sleeve for 4th gear.

 

So, while the shaft may be supported by the pilot bearing, the play at the other end may or may not affect those shims.

 

In my last transmission I rebuilt (100K miles), it did, and tore those up, which I found fragments in my fluid and damaged 4th gear to the extent that I had to use my "NOS secret stash only use in emergency mega buks I don't know when or where I acquired them" spare gear set. After confirming with a borescope.

 

BTW, it too, shifted "Buttery Smooth" and wasn't noisy.

 

In the end, make a jig and measure it. IIRC the end play should be in the Blue Manual.

 

the good news is that you already have it out of the car.

Would love to hear more details about what I can do to tighten things up.

 

 

9 hours ago, TobyB said:

240, 242, whatever it takes!

 

I'd not worry.

 

 

t

won't live that long 

 The trans wont live that long???

[Einspritz]

The only way that I know to "tighten things up" is to have a rebuild by someone who will take the time to actually measure and shim the transmission properly. You know, using the Factory Specs.

 

Perhaps seek out "the OLD guys" preferably those who were factory trained "back in the day". I was mentored by a Factory trained (at the actual factory) mechanic in all things '70s-80s BMW, but could never get the transmissions "right". So, guess who got to remove them again (my free labor, not the shops) when they failed after a short time? ditto for differentials.

 

BTDT to great expense.

 

Now I take an obsessive view on just WHO is to rebuild, and the "Warranty". But guess who gets to take it out again, and box it up and ship it Again?

 

So, how much is your time and lost enjoyment worth if you have to remove it again?

 

Since I usually drive as my heritage genetic predisposition, I'd rather not have to always wonder when my transmissions are going to go out.

 

Unless you "Money Shift" it... as the input shaft bearing is only good to 6500 rpm on those transmissions.

 

 

[tech71]

On 2/25/2021 at 3:19 PM, flagoworld said:

Seems to be buttery smooth in all gears...

 

On 2/25/2021 at 9:44 PM, TobyB said:

That shaft can float a LOT before it does any damage.

New pilot bearing and run it!

It's a 240 after all, they can still be had for less than the price of your first born child.

Edited February 28, 2021 by tech71

[flagoworld]

15 minutes ago, Einspritz said:

The only way that I know to "tighten things up" is to have a rebuild by someone who will take the time to actually measure and shim the transmission properly. You know, using the Factory Specs.

 

Perhaps seek out "the OLD guys" preferably those who were factory trained "back in the day". I was mentored by a Factory trained (at the actual factory) mechanic in all things '70s-80s BMW, but could never get the transmissions "right". So, guess who got to remove them again (my free labor, not the shops) when they failed after a short time? ditto for differentials.

 

BTDT to great expense.

 

Now I take an obsessive view on just WHO is to rebuild, and the "Warranty". But guess who gets to take it out again, and box it up and ship it Again?

 

So, how much is your time and lost enjoyment worth if you have to remove it again?

 

Since I usually drive as my heritage genetic predisposition, I'd rather not have to always wonder when my transmissions are going to go out.

 

Unless you "Money Shift" it... as the input shaft bearing is only good to 6500 rpm on those transmissions.

 

 

 

Would love for someone to share that procedure with me so I can give it a go... Unless its some kind of secret knowledge now. ?

[Einspritz]

Blue manual for your transmission.

 

Although I consider it an "art".

 

Pay particular attention to any special tools.

[TobyB]

Perspective:

 

this is a 4- cylinder gearbox that's hell to get apart, prissy to shim, and takes a significant amount of 

tooling to get apart and get back together.

 

It worked fine.

 

The input shaft wiggles a bit.  That movement is determined mostly by the end float between the input

and output shafts, and the pilot bearing that marries the two across the 3-4th gear hub.

The end float's cumulative across both input and output shafts, so it's not an indictment of the input bearing, per se.

 

The input ball bearing is hell- for- stout for the small amount of torque the M10 puts out.

Plus, it's captive in the pilots on BOTH ends.  It ain't goin' nowheres.  If it has measurable

motion IN PLANE, then it might be worth it, but wiggle at the end?

 

Dah.

 

Run it.

 

The countershaft bearings are far smaller than the input, and they take at least as much loading.

THOSE are usually what leads to a gearbox teardown- and then, once it's open, it's pound- foolish

not to just do all of them.

But it's also real money- synchros alone are up around $600 for all 5, and painfully, there are 

bad ones in the supply chain (including BMW).

 

My theory on why some input shafts are as-new and some are pretty floppy:

engine alignment.  If it's dead- nuts, the box never wears at all on the input

side, and stays tight until the countershaft falls out the bottom.

If the engine alignment isn't within 0.01mm, then the transmission wears 

to match the alignment, and then is a bit loose for the rest of its life.

If it's WAY out, it wears all to hell, and doesn't last too long.

It's surprisingly hard to get bellhousings landed on the block exactly precisely.

 

Eh, whaddevah,

 

that's just me.

 

t