Many other companies have attempted to make a VW 5 speed with little success. The True Shift 5 speed trans, formerly sold as the D-5 under the name R & N Engine & Trans or the Mikey from Oregon that is extremely similar, have come and gone and come again. Why do they continue to be offered as a new product over and over again? Possibly because this is simply not the proper way to build the 5 speed for strength or longevity and in fact is not as strong as a stock 40HP transmission. What other companies have done is try to copy my very first "proto" type which I made in 1965, the D-5, or the #2 prototype I made in 1966.
Unfortunately, many problems were encountered with these designs and I abandoned both of them without ever selling a single one, they did not pass our longevity tests. The "screw together extensions" on the shafts were a continual source of problems from 3/4/5 gear noise, to having shaft runout or simply breaking at the first thread. Our second prototype series utilized solid welded together shafts. However, it still did not cure all of the noise problems and failures were still a problem throughout the life of the box. Some shaft bending and gear breakage was still experienced with only what would now be considered a mild street engine.
One of the engineers we consulted explained that the length of the shaft in relationship to the size of the shaft and distance between bearing supports for the loads exerted by the pressure angles on the gears would not support even low HP ratings. Any good performance VW street engines are now developing far beyond this power today. The shaft was simply too small to prevent bending across that long of a span. (No the other company�s design will withstand an engine output of 580 ft. lb. of torque like they claim).
Thus, I developed and manufactured the 3rd design in which I moved the 5th gear onto the other side of the intermediate housing bearing affording the proper bearing support and shaft strength. Interesting that the factory Porsche and late 091 bus 5 speeds have the exact same design as ours.
This is considerably more expensive to build and slightly harder to fit into the car than the Mikey version or other copies of our proto versions, 1 and 2. However, this design has proved extremely reliable in vehicles with over 300 HP race applications and street cars running up to 190 HP for over 18 years.
So, if ours was so wonderful, why did we stop making it for so long? Two basic reasons. It took 5 years to sell 112 kits at a price of $742. Secondly, what we continually heard and still hear from many people we talk to today that want a 5 speed today, is that they are doing it to get an "overdrive". The problem is that "all" VW's ever made already have an overdrive in 4th gear. In my opinion, people who try to install a even higher than stock final drive for an air cooled VW are crazy. Our tests have proved conclusively over and over again that a higher overdrive causes the engine to get "less" mileage, and runs much hotter because the fan turns slower, which obviously shortens the life of the engine. Few people stop to think about what is actually happening when a higher overdrive is installed. You are giving the leverage to the car and taking it away from the engine.
Like moving the teeter-totter leverage out to the heavy person's side rather than to the light person's side. Thus, taking more HP to drive the car the same speed regardless of the size of the VW engine. More HP is more heat, less mileage and a shorter life. I tried a bigger pulley to speed the fan up again. However, it took more HP, which caused as much heat as it removed. I have found nothing to cure these problems so simply stay with the factory overdrive 4th gear in the 5th location.
Maybe VW was smarter than many give them credit for. After all, if simply installing a higher overdrive would provide more mileage, longer life and better cooling you would think the first people to do so would be the VW factory. See GB 801-GEARING and GB 801-COOLING for more information.
I designed the 5 speed so people could have a close ratio 4 speed gear box utilizing and keeping the stock overdrive gear in the 5th gear position. Naturally, racers use them with all 5 close ratio race gears. Yes, with our Berg shifter you can speed shift all of the forward gears, even 5th.