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SAND / OFF ROAD
RACING TRANSAXLE
WE HAVE DEVELOPED 3 MAJOR MODIFICATIONS TO THE VW 091 BUS TRANSAXLE THAT
WILL MAKE OUR NEW 091 PLUS THE BADDEST VW BASED TRANSAXLE ON THE PLANET. VW
TRANSAXLES HAVE BEEN EVOLVED BY TALENTED AND INNOVATIVE INDIVIDUALS OVER THE
YEARS TO PERFORM AGAINST RIDICULOUSLY HIGH HORSEPOWER AND SUSPENSION LOADS
COMPARED TO WHAT THE VW ENGINEERS ORIGINALLY INTENDED. THE 091 BUS TRANSAXLE IS
STILL THE BEST PLATFORM FROM WHICH TO BUILD A VW BASED PERFORMANCE TRANSAXLE,
BUT THERE ARE SEVERAL WEAK POINTS WHICH WE FEEL HAVE NOT BEEN ADDRESSED UNTIL NOW. THE BIGGEST
FAILING ON THESE GEARBOXES IS RING & PINION BREAKAGE, AND OF COURSE THE
BEST ANSWER TO THAT IS TO STEP UP TO A MENDEOLA MD4-E TRANSAXLE, BUT THERE ARE
2 PROBLEMS TO THAT SOLUTION; ONE IS THAT 16 CLASS OFF RACERS ARE NOT ALLOWED BY
SCORE RULES TO RUN ANYTHING BUT A VW GEARBOX AND THE OTHER PROBLEM IS THAT A
MENDEOLA TRANSAXLE DOESN'T FIT INTO EVERYONE'S SAND CAR BUDGET. WE FELT THAT WE
COULD IMPROVE THE 091 TO A DEGREE THAT WOULD PUT IT INTO ANOTHER CLASS AS FAR
AS RELIABILITY GOES, AND
STILL KEEP IT RACE LEGAL AND IN AN AFFORDABLE PRICE RANGE.
HEAVY DUTY ALUMINUM 091
INTERMEDIATE HOUSING
THE AVAILABILITY OF VW BUS CORE TRANSAXLES HAS BECOME A PROBLEM
BECAUSE OF THE HIGH DEMAND FOR SAND AND RACE TRANSAXLES. IT IS EASY ENOUGH TO
IMPORT 091 CORES FROM GERMANY, BUT MOST OF THEM SHIFT FROM THE SIDE OF THE NOSE
CONE. A RELIABLE SHIFT LINKAGE FOR THESE TRANSAXLES WOULD BE EXPENSIVE TO
PRODUCE. THE SIDE-SHIFTING TRANSAXLES CAN BE CONVERTED TO THE TRADITIONAL
FRONT-SHIFT CONFIGURATION, BUT THIS REQUIRES A FRONT SHIFT INTERMEDIATE
HOUSING, AND THESE ARE IN SHORT SUPPLY. FOR THIS REASON WE DECIDED TO PRODUCE A
HEAVY DUTY ALUMINUM HOUSING TO ACCOMPLISH THIS CONVERSION. AS LONG AS WE WERE
PRODUCING THIS PART ANYWAY, IT SEEMED A LOGICAL NEXT STEP TO CREATE A BETTER
ONE. OUR INTERMEDIATE HOUSING USES A LARGER MAINSHAFT BEARING THAN THE STOCK
091, THE SAME BEARING USED ON STOCK MENDEOLA MD4-2D AND MD-5 TRANSAXLES. THIS
ALLOWS OUR NEW 091 PLUS TRANSAXLE TO ABSORB HIGHER RADIAL AND THRUST LOADS. THE
NEW HOUSING USES A STEEL BEARING RETAINER, SO THE MAINSHAFT BEARING CANNOT WEAR
INTO THE SOFT MAGNESIUM NOSE CONE.
FLANGE BEARING
RETAINER
A COUPLE OF YEARS AGO WE WERE APPROACHED BY A SAND CAR OWNER WHO
WANTED TO RUN A TYPE I VW TRANSAXLE IN A VERY LIGHT MID-ENGINE SAND CAR WITH A
SUBARU ENGINE PRODUCING AROUND 300HP. WE SUGGESTED A MENDEOLA MD4-E TRANSAXLE,
BUT THIS PARTICULAR CUSTOMER WAS MORE CONCERNED ABOUT THE WEIGHT OF HIS CAR
THAN THE COST, AND INSISTED ON A TYPE I TRANSAXLE. WE BUILT HIM A VERY
EXPENSIVE TYPE I TRANSAXLE UTILIZING SUPER-SPLINE SIDE GEARS, AND WE BORED HIS
SIDE COVERS TO ACCEPT OUTBOARD BALL BEARINGS AT THE CV FLANGES TO PREVENT
SUSPENSION LOAD FROM BREAKING THE STUB AXLES. THAT TRANSAXLE PERFORMED VERY
WELL, AND OVER THE NEXT TWO YEARS OR SO WE BUILT ABOUT A DOZEN MORE LIKE IT.
AFTER A FEW OF THEM STARTED COMING BACK FOR OVERHAULS, USUALLY JUST A BLOWN
REVERSE GEAR OR WORN SYNCHRO RING, WE NOTICED THAT NONE OF THEM HAD BROKEN OR
EVEN SUBSTANTIALLY WORN A RING & PINION, AND THESE CARS WERE RUNNING MORE
SUSPENSION AND HORSEPOWER THAN A TYPE I SHOULD BE ABLE TO HANDLE. WE CONCLUDED
THAT SUSPENSION LOAD IS A MUCH MORE IMPORTANT FACTOR TO RING GEAR LIFE THAN PREVIOUSLY
THOUGHT. FOR THIS REASON WE ARE NOW PRODUCING A STAINLESS STEEL BEARING
RETAINER FOR THE 091 TRANSAXLE THAT WILL ALLOW FOR INSTALLATION OF OUTBOARD
BALL BEARINGS BEHIND THE CV FLANGES, TRANSFERRING THE SUSPENSION LOAD OFF OF
THE RING GEAR AND INTO THE CASE. WE FEEL THAT THIS WILL SUBSTANTIALLY INCREASE
RING & PINION LIFE AND ALLOW THE 091 TO HANDLE MORE SUSPENSION AND
HORSEPOWER THAN PREVIOUSLY POSSIBLE.
INPUT SHAFT BEARING
ONE OF THE FAILING POINTS OF THE VW 091 TRANSAXLE IS THE CENTER
MAINSHAFT BEARING. THE ENTIRE WEIGHT OF THE CLUTCH ON A STOCK VW TRANSAXLE IS
CARRIED BY THE PILOT BEARING ( A TINY NEEDLE BEARING LOCATED IN THE FLYWHEEL
GLAND NUT),AND THE CENTER MAINSHAFT BEARING, (ALSO A NOT SO LARGE NEEDLE
BEARING). THE RADIAL LOAD IMPOSED BY THE ROTATING MASS OF THE CLUTCH IS ALSO
CARRIED BY THESE TWO SMALL BEARINGS, AND THE 091 OFTEN EXPERIENCES DESTRUCTION
OF THE MAIN CASE WHEN THE CENTER MAINSHAFT BEARING FAILS. WE FEEL WE HAVE
SOLVED THIS PROBLEM WITH OUR 091 PLUS TRANSAXLE BY INSTALLING A BALL BEARING IN
THE BELL HOUSING. THIS MODIFICATION REQUIRES A SPECIAL THROWOUT BEARING COLLAR,
PRODUCED BY TRANSWORKS, AND MODIFICATION OF THE INPUT SHAFT, AND CAN ONLY BE
FOUND ON THE TRANSWORKS 091 PLUS. |
