Bus transmission questions

[HeyWatchThis]

So I've read through the pinned transmission post a few times and I'm sure I'll go through it again, but I'm not 100% tracking on what works with what.

I have a 1968 Baja with the original swing axle transmission (suspension) and a later 1600dp engine. I was thinking for next winter I could maybe build or rebuild a 1914-1956cc motor and swap over to a bus transmission, but I would like to make sure I'm looking at/for the correct thing before I get much past daydreaming here.

Also, what is the story with reduction boxes? It seems like a great idea to get the back end a little higher without camber issues, as well as reducing the gearing for larger tires, but maybe there are limitations? or availability or maintenance issues?

[jsturtlebuggy]

Do you already have the inner pivot points on your torsion housing for IRS trailing arms. I know you said it is a 1968 swing axle, just asking as something you will have to do if they are not their.
A IRS setup allow more wheel travel then a swing axle.
If you decide to use a Bus swing axle with reduction boxes to eliminate the hop you need to do some modifications and fabrications to make it work.
_________________
Joseph
Fair Oaks/Orangevale, CA
Elrod Motorsports
Motion Tire Motorsports
Having fun with Dune Buggies since 1970
Into Volkswagens since 1960

[Mal evolent]

1968 swing axles are wider than earlier years, split window bus guys like them to eliminate the reduction boxes and lower their rides. Don't fling them if you change your trans.

The bus gearboxes in question are IRS transmissions. you have to pound big dents in your frame horns to use them in a sedan. It's a CV flange clearance issue. I would reinforce the frame horns with thick straps if I did that

Reduction boxes are swingaxle only. you can widen and raise the rear end, or lay them down horizontal which widens the rear end and lengthens the wheelbase.

there have been attempts to modify reduction boxes for IRS. I believe the effort / success ratio is right up there with perpetual motion.
_________________
73 Beetle Baja, Ghia front brakes, Type 3 rear brakes, 2220 ( 94 X 80 ), Weber Progressive, Bosch SVDA, '97 Mustang seats

Baja Bugs for Volkswagen Virgins: Index

[HeyWatchThis]

There are not currently any pivot points for IRS. Stock early '68 SA.

Am I correctly reading that I will have to convert my rear end over to IRS to use a bus transmission at all? Swing axle bus transmissions will not work?


Next question I guess is how much "better" or stronger is a bus gear box vs. sedan?

My stock tranny is holding up fine so far, but I'd like to put slightly larger tires (30-31" vs. the current 29's) and a bigger motor (1900's is where I'm looking). Just don't want to set myself up for failure.

[Vanapplebomb]

What bus transmission are you taking about? Are you taking a swing axle with gear reductions, or the 68 and newer irs bus transmission?

To use the heavy duty irs bus transmissions you will need to convert to irs. To use the early gear reductions, no need to add pivots for irs, but you will need adapters to use the bug spring plates with the gear reduction boxes.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Mal evolent]

a swing axle bus transmission is a swing axle transmission with the ring gear and carrier flipped. same ratios, different rotation. the ring gear is flipped because the reduction box reverses rotation

when off road VW people talk bus transmissions they refer to the 3 rib 002, the 5 rib 002 and the 6 rib 091 IRS transaxle

the early 3 rib 002 is a stronger case, same gears as the beetle, 5.38 R&P

swiped from: https://www.thesamba.com/vw/forum/viewtopic.php?t=492880

[jsturtlebuggy]

If you are looking at installing a swing axle Bus trans with reduction boxes, there are two ways to install one.
The way it was done at first was to a 1in thick block of steel or aluminum and modify the spring plates to fit. The block looks like a large J as it bolts on the reduction and then bolts the the spring plate with holes you have to drill.
The setup will make the rear of the car hop up when you accelerate because of the reverse rotation of axles.

The method I prefer requires more work to install and requires the reduction boxes to be pressed off and one the axle tube.
This set up does not make the rear of the car hop up. We did this long before there was ever a Johnny Johnson NO HOP KIT.
It uses the stock spring plates.
What has to be done is to disssemble the reduction boxes and remove the axle tubes from the transaxle itself.
Then you press off the reduction boxes off the axle tubes.
Once you press of the reduction boxes, you cut 1in off the end of reduction box where is slips over the axle tube.
Then you going to need to measure the axle tube out diameter and find some steel tubing to slip over the tube. If I remember correctly it was 1-3/4in .095" wall tubing. It going to be about 6in long.
You are going to need to find exhaust flanges (or make your own) that have the bolt pattern of the spring plate where the stock Bug axle tubes attach.
This is going to be used as the pivot point and the mounting of the bus axle tubes.
You are also going to need to fabricate brackets for lower pivot point and on the reductions boxes for a strut that going to attach and forward to the torsion housing.
The stut need to be very strong as it going to need to be handle all the torque of the engine.
Both my Dads and my Baja Bugs used the lower shock mount on the reduction boxes for the stut attachment point.
You will need to fabricate a mount for the forward attachment point for the stut. Welding the mount to the torsion housing and making sure it aligns with the rear attachment point.
I used strut that came off a Volvo. ( This was in the 1970s) The local Pick N Pull and imagination can help you find ones that work. Use grade 8 bolts.
People have tried using Heim joints for this, all it does beat them to death. Better to use rubber or urethane so it will absorb some of the shock loading.
Then you are going to need to fabricate lower shock mounts on the reduction boxes. There are 4 bolt holes 12x1.5mm in reduction box to use.

For picture of what was sold years ago, Look up Johnny Johnson NO HOP kit as this may help you with what need to be done.

Remember installing a Bus trans with reduction boxes will not give you more suspension travel, it will only raise the rear by approx 3in.

Istalling a Bus IRS transaxle requires work too. You have to add the inner pivot points for the trailing arms to the torsion housing. This requires welding and cutting tools.
There are several ways of installing the Bus box in a Bug. Some are describe in above posts. Now the make different gear carriers for installing the trans and use a Bug shift housing (nose cone).
With the IRS setup you can get more suspension travel, and it kind like the sky is the limit.
All it takes is a lot money.
Best of luck with your project.
_________________
Joseph
Fair Oaks/Orangevale, CA
Elrod Motorsports
Motion Tire Motorsports
Having fun with Dune Buggies since 1970
Into Volkswagens since 1960

[HeyWatchThis]

Thank you gentlemen for the information, that's exactly what I needed to know.

- Swingaxle with reduction boxes ---> Adapters for sedan spring plates

- IRS 002 or 091 ---> Modify existing suspension to IRS, then modify for Bus trans axle to fit.

[Multi69s]

On my 69 (with IRS) I first installed an early 002 with 5:38 R&P. I used the 10 degree mount (made my own) so the shifter would go in the tunnel. Then used 15-5/8" axles with Type 2 CVs, and thing stub axles. With this setup, stock motor, and 30" tires, I could just about anywhere. However, freeway RPMs were too high (4,000) at 70mph. On the installation, I did not need to dent the frame horns for CV clearances. However, I did have to cut part of the frame horns inner flanges and re-weld then.

Fast forward, I am now running a 2010 engine, swapped the trans for the 1975 - 002 (4:86 R&P), and went to type 4 CVs for more travel. I now have lower RPMs on the freeway, and of course with a bigger engine, I can hit it a little harder.

Just a side note, since you have a heavy car (Baja), don't go wild on the cam. You need good low to mid to get out of holes etc. When you have to scream the engine, parts start to break.
_________________
69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
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