Date:         Wed, 25 Nov 1998 01:37:58 EST
Reply-To:     Jwilli941@AOL.COM
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Todd Hill <Jwilli941@AOL.COM>
Subject:      Re: Bearing load on reverse driven transaxles
Comments: To: vanagon@vanagon.com
Content-type: text/plain; charset=US-ASCII

  jjvantol@USWEST.NET writes:

(Just please remember that this is all quoted out of context)

<<  Well, actually, with the helical gears that isn't true. There's
a  significant amount of longitudinal loading on those bearings,
which is why they usually use double tapered roller bearings...>>

The only place a double tapered roller bearing is used in
the Vanagon gearbox is the pinion shaft.  The mainshaft
is supported in the front by a ball bearing with an inner
race designed to accept a very small amount of longitudinal
load.   The halves of the gearsets that are free spinning
ride on caged needle bearings as well.  They do float back
and forth very slightly when not under load but once the
slider locks in the torque is transferred axially through the
main or pinion shafts.   If the torque was transmitted
longitudinally (Man!  What a word!)  then you'd be blowing
the gears down the shafts and out the ends of the gearbox.

 <<The helical ring and pinion gears may not work so well in
reverse, as the load bearing surface would be the opposite side.>>

The Split window Busses up to '67 ran a Beetle transaxle with
the differential on the opposite side.  The pinion head drove the
coast side of the ring gear due to the reduction gear box design-
2 spur gears which reverse the direction of axle rotation.  If the
VW engineers where concerned with driving the coast side of
the ring gear then they would have had 3 gears in the redux
boxes.  Now, the Type 1s ran a helical cut ring and pinion set
but not a true Hypoid like the later Busses, Vanagons, and
Audis.  This means that the pinion head intersected the ring
gear at... say the 3 o'clock position when viewed from the
side.  With a true Hypoid the cut of the ring and pinion is much
more 'swirled' and the pinion intersects the ring gear more like
5 o'clock.  Frankly, I don't know how that would effect a ring
gear that was driven on the coast side like the early Bus.

 <<May not be a problem, or it may be. I just remember that if
you run a Corvair transmission backwards, it isn't supposed to
last long at all.  >>

Perhaps that was marketing to sell reverse camshafts and
so forth??  ;)

-Todd Hill
 VolksWerks Transaxles
 Olympia, WA