3rd-4th spacer or spring?

[Bruce2]

Is there any advantage of the solid spacer vs. the spring on the pinion shaft of the late gearboxes?

The US Gear made 3.44s don't have the groove for 3rd gear circlip, so you have to use the solid spacer and bellville washer to provide the load between the gears. My problem is that I don't do early gearboxes, so I don't have any spare spacers. Plus, the clip and spring are so much faster to build. I'm wondering why US Gear was directed to not put the groove in. Anyone know?

One thing's for sure, I'm going to have a bunch of pinions modifed with the groove.

[Marc]

...I'm wondering why US Gear was directed to not put the groove in. Anyone know?...

Maybe whoever spec'ed 'em shared Gene Berg's feelings about a solid sleeve being better than any stock spring-loaded setup:
http://www.geneberg.com/cat.php?cPath=12_373_2909

[Pablo2]

I would agree with machining the groove back in. Ridiculous that it's left out. On a late pinion (3.88), I use the inner circlip, set the 4th gear on for measurement purposes, and machine a spacer to fit snugly between 4th and the circlip. If using a stock early spacer, this usually requires a couple shims. The spacer should barely be able to be turned when 4th is pressed down hard.

The outer circlip groove is then cut a tad deeper (this groove is ridiculously shallow), and a small, thin shim goes between 4th and the outer circlip.

4th gear is of course flipped and fit with a thrust washer as per previous threads, so the entire stack is captive.

No Bellevilles or spring washers, ever ..

[dangerous]

You have to remember that VW made changes to save money and time as a priority,
but also made 'upgrades' that may give longer service life,
but not necessarily better for higher power applications, and continued trouble free gear positioning.

Fine tooth gears and circlips, are a classic money and time saving exercise,
and splines are one such thing that is actually better for both cost and performance.

If you prefer to use the factory fine tooth gears and sprung spacer,
then, yes, you will need a circlip on 3rd gear.

When you buy the aftermarket "nut" style pinion,
they should supply the nut
and aftermarket solid spacer,
or at least tell you that it is needed.

The factory early spacer is not wide enough to rest against 3rd gear
so it must use the original early concave washer/s.
I use two, and do away with the shims that VW adds at this location.

So if the pinion has a nut on the end, it does not need the 3rd gear
circlip, if a sold spacer is used.

VW used a circlip on the end to save the cost of making a nut and lock washer,
and thread on the pinion,
and so it needs some spring load to stay in position.
Therefore the location of 3rd also needs a circlip,
because under power, the helix of the gear would just compress the spring.

On these circlip style pinions,
The 3rd gear circlip also should be used when using a solid spacer because the 'end' circlip does not have enough capacity
to handle the load transferred to it from the axial load of 3rd gear.

If the pinion end has a circlip,
then over time the use of a solid spacer eventually becomes loose.
...unless a lot of Loctite is used,(yuck), or the engine has no torque.

This is a problem even on the early trans,
so for the old trans I use the original spacer and 2 concaves,
but on higher torque applications, the aftermarket thick wall spacer instead,
because the thing VW spacer wears and loses length.

On circlip pinions, the 3rd
gear end of the solid spacer needs a wider platform,
and early concave washers
are too large in the bore for the late shaft
so I modify concaves from the main shaft end
to fit over the pinion, and set up the length to provide a solid distance.

This is how I set up the aftermarket pinions with the nut on the end.
For the nut type I see no point
in using the sprung spacer unless you are helping to cushion the use, of the fine tooth gears

I think the spring spacer is a good cushion, for the fine tooth gears,
and keeps tension on the circlip on the end to keep it engaged (with its taper matching the tapered groove),
but if the pinion does not have a circlip on the end, then no spring is needed.

[Bruce2]

Thanks for the detailed reply, Dave!

My customer demands the quietest gearbox possible, so that means I use fine tooth gears.

I found one incompatibility with the last one. I wanted to use late 002 type Beetle gears on the 3.44 pinion shaft. Some late 3rds have a reduced web between the splines and the gear teeth such that you cannot use the stock spacer and concave washer. The flat area where the circlip bears against the gear isn't large enough in dia to support the concave washer.

Here's a pic of an early fine tooth 3rd and a late one with the step in it:

http://images.thesamba.com/vw/gallery/pix/1366651.jpg

[Bruce2]

VW used a circlip on the end to save the cost of making a nut and lock washer,
and thread on the pinion, and so it needs some spring load to stay in position.
Therefore the location of 3rd also needs a circlip, because under power, the helix of the gear would just compress the spring.

The helix angle causes third gear to be pushed towards the pinion, so it can't compress the spring. 4th gear could, but it rests against the solid step in the shaft.
On decel, the gears push towards the front of the car. Is that what you meant?

For the nut type I see no point in using the sprung spacer unless you are helping to cushion the use, of the fine tooth gears

Why do you think the fine tooth gears need a "cushion"?

The last 3.44 gearbox I built is now popping out of 2nd gear. It was driven locally for about 300km and worked well. Then one day it popped out of 2nd on decel. Since that first incident, it pops out every time with ease.
This trans was built with the stock spacer, spring washer and shim. I can see that if there was a lot of travel in the spring washer, the 2nd gear idler and 3rd gear could move axially towards the front of the car, causing it to lose engagement with the slider. But the amount of spring travel I left it with couldn't have been more than .1 or .2mm, so I don't see how it could be the cause.

Then I read this in the blue Bentley:
"The quiet running of the rear axle will be adversely affected if the clutch gear and 3rd gear are tightly seated without backlash. This is the case when the concave washer is adjusted too tightly. If the maximum spring deflections is exceeded, the 2nd gear will tend to jump out of engagement."

Is this warning from VW BS? It seems like everyone sets them up tight, and how can being in a stable position cause it to pop out of gear?

[paul_f]

I have a late 3.88 pinion that I am building for my 2.3 type 4 split bus with 113 coarse 1.23 and 0.89.

I was able to find a shim and a circlip so I have no play in 3rd.

I haven't cut the snap ring groove deeper, so should I just use the stock spring spacer?

I don't think I can do the thrust mod as I am not using a close 4th - the washer partially covers the teeth of the gear.

[img]//images.tapatalk-cdn.com/15/08/09 ... 0a89e0.jpg[/img]

[nshaddox]

Then I read this in the blue Bentley:
"The quiet running of the rear axle will be adversely affected if the clutch gear and 3rd gear are tightly seated without backlash. This is the case when the concave washer is adjusted too tightly. If the maximum spring deflections is exceeded, the 2nd gear will tend to jump out of engagement."

Is this warning from VW BS? It seems like everyone sets them up tight, and how can being in a stable position cause it to pop out of gear?

I think that the bentley warning is 2 separate statements. 1) if too tight, quiet running is adversely affected. 2) if too loose, 2nd gear will tend to jump out of engagement.

Therefore, after 300k miles on the box in question, I would guess that the maximum spring deflection is now worn past where it needs to be for 2nd gear to jump out on decel.

[Dougy Dee]

nshadox: Uhhh...300km is roughly equivalent to 186 miles.

[Bruce2]

Then I read this in the blue Bentley:
"The quiet running of the rear axle will be adversely affected if the clutch gear and 3rd gear are tightly seated without backlash. This is the case when the concave washer is adjusted too tightly. If the maximum spring deflections is exceeded, the 2nd gear will tend to jump out of engagement."

Is this warning from VW BS? It seems like everyone sets them up tight, and how can being in a stable position cause it to pop out of gear?

I think that the bentley warning is 2 separate statements. 1) if too tight, quiet running is adversely affected. 2) if too loose, 2nd gear will tend to jump out of engagement.

After re-reading it, I think you're right. I can see that if there's too much axial play, the trans will pop out of gear. But how can being tight cause noise?

Therefore, after 300k miles on the box in question, I would guess that the maximum spring deflection is now worn past where it needs to be for 2nd gear to jump out on decel.

Dougy was right. This gearbox had only a couple of weeks of driving, about 300km.
The real reason it was popping out of second was due to the 3.44 pinion shaft not having a groove for 3rd gear. The whole gear stack relies on the nut on the end. In my case that nut backed off a couple of turns, allowing all the parts on the stack to move forward. In other words, 2nd gear idler shifted away from the 1-2 slider.

[nshaddox]

oh, i definitely misread the 300km as 300k km. my bad. interesting though, if the nut had just backed off, can you just simply tighten it back up and lock it in place somehow to correct?

I believe the reasoning behind the noise for lack of lash is given elsewhere in the bentley. seem to recall something about resonance frequencies. Maybe someone can do a FEA and dispel those concerns. ha. I'll look through the bible . . . I mean bentley . . . tonight to see if I can find it again.

[Casting Timmy]

An interesting thing I saw lately was Weddle with a new heavy duty spring listed for 113/022/091. Is it just the 091 spring or did they design a spring with the 091 force but works for either application?

[Bruce2]

Here's the upgraded spring Tim is talking about:


Am I reading it right that this spring comes in an 091 gearbox? And if so, does it also come in a 76 and later Type 1 'box?

[Casting Timmy]

I asked Weddle about this and they said it was a new VW part and not their design. I might order one next time and see what's different about it.