Lottery Trans Odd Noise

[Clatter]

OK,
This is a long shot, but maybe one of you has some ideas..

Because my last trans died, I went to the Pick 'n Pull and played the lottery.
'Lucked' into a late 3:88 shift-rib, cleaned it up, filled it with some cheap GL4 i had lying around,
stabbed it into my beetle, and took it out for a spin.

Lucky me! It seems like it all works really well,
Shifts easy, quiet on coast and accel, no clunky shifts or odd noises!
WhooHoo!!
After it's maiden voyage on the highway, getting good and hot,
dumped the cheap oil and loaded it up with some Swepco 201.
A few tiny little feathery flakes on the drain plug, but no pieces or parts.

Now, a couple of months sitting later, I got my fairly-hot 1914 done and installed,
go driving around town, and all is well.
Now that the motor is getting broken in, it gets run hard on the highway..

Above 75 or 80-90MPH, decel sounds bad.
Like grinding gravel rocks..
Since the car has a urethane nose cone, padded strap kit, Kafer bar, urethane coupler, and Hurst shifter,
It made me think that there was a shifter/linkage rattle.
Would make sense that the vibrations would set off some kind of gravelly rattling, right?

But,
Dag,
It also sounds like a bearing kind of going,
But it's not a squealing like a bearing, more of a grindy rattle like a shifter..

Hard to describe,
And just goes away at like 70 or 65 or under.

Does anyone have any ideas about how to diagnose what this might be?
Is there some trick to check?
Holding my hand on the shifter doesn't make the sound go away.

What would be a possible worst-case scenario here?

Dag, this thing just works too well in all other ways.

Sorry, long dumb post, but any input is welcome.

[Dougy Dee]

The flakes could be from the Mainshaft sliding in the MS bearing or case allowing 4th gear teeth to machine the case.

[Clatter]

I think I found something this might be..

Was digging around here, and found that I might have made a mistake when I switched out the nose-cone.

Can't find the dang post anywhere to quote it,
But,
There's a plastic roller cage on the pinion shaft bearing in the gear carrier, right?
And it sticks forward..
And if you switch from a 3-bolt late nosecone to a two-bolt to make it fit your car,
You'll close up a gap, and the plastic bearing cage will contact the nosecone.

The solution can be one of those thin bearing retainer plate thingys,
Or clearance your nose cone.

So, my question...
This could make noise on decel at speed, right?
The pinion shaft is forced forward some (front of car) when the throttle is lifted?

[Clatter]

You could just put a pre`73 nosecone on it, but there are issues - the late mainshaft bearing isn't really compatible with the 2-bolt nosecones. Personally I use an aftermarket conversion mount instead. Late chassis have a stud on the LH framehorn for the ground strap (the other end goes to a sidecover stud/nut or bolt); you can weld one onto your chassis or simply use one of the rear mount-to-carrier bolts - it's not a good idea to try and put the ground strap in the early stock location with these urethane mounts. Also, the steel tubes should be a snug fit in the bores of the mount. If they aren't, enlarge their diameter with metallic ductwork tape.

http://vwparts.aircooled.net/Late-3-Bol ... -21-bl.htm

The plastic ball seperator on the bearing hits the earlier nosecones. I have seen cases where the bearing was turned over and then the seperator is on 4th gear side and the nosecone can't hit it then.

You can use a thrust plate and the cage/seperator will clear. Or you can clearance the nose cone..mill, burr bit, etc.

[Bruce2]

If you have a grinding noise and you think it's due to the nose cone not clearing the plastic cage, that means the plastic cage has been ripped out. When this happens, the balls go to one side creating a misalignment of the mainshaft.
If you take it out right away, you can probably get away with putting another plastic cage in the bearing. Then clearance the nose cone to clear it.
The last time I installed an early nose cone with the late bearing, I clearanced the plastic cage instead of the nose cone.

[Clatter]

Couple of years later...
Got a chance to open this one up.
Didn't drive it much.

A late shift-rib SSC with an early nose cone just slapped on.
Indeed the plastic cage was chewed up,
But it looks like i caught it in time?




This trans shifted perfectly and was super quiet.
Think it's OK to run?
The main-shaft race moves about .020 in the gear carrier..



Would the plate dealie give me a shot at running the thing?


It says you have to machine the nose cone?
Is this also the case when running an early cone on a later trans?


Seems like you'd get your clearance by just gluing it on,
The bearing would be supported,
And Bob's your uncle, right?


Nose cone is pre-clearanced!


Anyhow,
Wondering how the trans masters would approach this situation..

Thanks for your time and wisdom,
Steve

[Bruce2]

Is the nose cone in your last pic a two bolt or 3? If it is a 2 bolt, it is the relatively rare Type 181 nose cone. This nose cone is designed to work with the late bearings but still uses the early 2 bolt rubber mount.

Clean up that nose cone then you need to reface it. Just outboard of where it is clearanced for the cage, is where it is normally in contact with the outer race of the top ball bearing. If you look at it, the bearing has pounded a groove in the nose cone. Even though you're going to install the steel plate, if there's nothing on the nose cone side of the plate to support it, it will bend. You should sand the gasket surface of the nose cone down until the groove is gone. Start with 60 grit on a flat plate or piece of glass.

Beware, in step 6 of the instructions with the plate, use 11 ftlbs, not 14. That is a big mistake.

The noise you reported may be partly due to your engine's hp. Since you have more than stock, the axial force that occurs on the top main shaft is more than stock. The clutch gear (aka shift hub) is a press fit on it's splines. When you're applying full power in 3rd gear, the 3rd idler gear on the main shaft pushes against the clutch gear. The extra axial thrust of your bigger engine will actually move the clutch gear on the shaft, pushing it towards 4th gear. When this happens, you no longer have any axial play for 4th gear. There is a thrust washer between 4th gear and the top bearing that gets chewed up in this situation. The cure is to machine a slight spot face on the 4th gear side of the clutch gear, then use the thicker 091 circlip. The 091 clip is 2.5mm thick instead of 1.5mm, so it doesn't bend.