The ultimate solution for putting a bus IRS gear box into a sedan, 1960-1967 bus, Thing or buggy.
The performance and reliability of the VW engine has continued to improve over the years so that reliability is no longer a problem with our quality parts. The gear boxes, however, have simply not kept abreast. True, we have developed many excellent building procedures and quality products over the years that provide the best longevity possible. However the sedan gear box, due to the design type of the ring, pinion and case, will never supply the reliability that is required to have a consistent super high performance street, off-road or race car.
Our solution to this problem in the off-road race car that we were involved with in late 1969 was to install the IRS bus gear box because it had a highpoid ring and pinion design. This design is the same as used in most all other vehicles and is far stronger than the straight line standard VW sedan ring and pinion. This early sedan straight line design is used because it requires less HP to move the vehicle, enabling the applications of small engines to provide better mileage.
These have proven to be virtually trouble free with engines developing well over 100 HP and even up to 190 HP if not abused and properly built, however when abused failure is inevitable. How long before failure was determined by the quality of parts, proper installation as described in GB 801-TRANS technical article, properly working suspension of the vehicle (GB 801-SUSP), and lastly, how hard and often you abused it. The IRS bus with the highpoid design has demonstrated for years, in both off-road and drag racing, that it will withstand far more abuse without failure. It may require slightly more power to drive through this design, however, the reliability factor far out weighs the small loss of power (or mileage) involved.
Tired of missing shifts and losing races with your bus IRS gear box? The Berg BUS600 intermediate housing conversion is a permanent cure. Many people have installed these gear boxes in vehicles in the past, however, simply using a mounting kit and the transmission's original design for the shift mechanism in the gear box, attaching it to the sedan was horrible. Mounts with straps simply do not provide adequate support, especially when hooked to the engine mounting bolts (see GB mounts). Next, the shifting required cutting a hole in the body for the shift rod to come through. You had the choice of doing away with your emergency brake and putting a new shift box on top of the tunnel or adapting back into the tunnel with a shift spacer. Unfortunately, the adapter never worked properly and few people will give up the emergency brake. Needless to say, both methods fall far short of working like the original VW sedan design.
Our prototype product that solved all of this was made in 1983 and was shelved for lack of interest by the buying public. Now it seems the people are simply not willing to put up with inferior installations that do not bolt in, work, or shift properly and demand this Berg quality product.