Snowcat Operations
Active member
DOES ANYONE KNOW HOW MUCH HORSE POWER A 1976 SNOW MASTER TRANSAXLE CAN HANDLE ON A DAY TO DAY BASIS? (Max HP too if anyone knows)
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Snow Master Transaxle max HP
- Thread starter Snowcat Operations
- Start date
What's the basis of the transaxle? Is it based on a VW or Porsche unit, is it based on some other OEM unit, or is it custom? I assume it has multiple forward gears; how many? Is first gear synchronized? What about the other gears? Are the gears helical or straight cut?Snowcat Operations said:
Does it use 1 CV joint per axle (like the early VW swing axles), or 2 per side? Or no CV joints at all? Does it use straight roller bearings, tapered roller bearings or ball bearings for the axle bearings (if any)?
There's no magic formula to which I can plug in all those facts and come up with a specific horsepower number, but I have a lot of experience with transaxles, engine swaps and race car construction, and I can probably come up with some guidelines if I have enough information.
How much horsepower are you thinking about? And, perhaps more importantly, how much torque? What type of engine?
Of course, if anyone simply knows the answer, just ignore my questions.
Lyndon
Bronze Member
VW Transaxle's can handel up to 100 HP in their original application, in a 'Bug'. They were actually manufactured by more than one company early on. They generally last 150 to 200 thousand miles in a Bug, an 120 K in an Bus or Transporter. In the ST4 Application there is additional gear reduction. Stock for a SNow Trac is 36:12 or a "3 to 1" Ratio. On the "Masters" ( Snow Master & Trac Master) it's 42:11 or about 3.8 to 1. An interesting side note is that if both the Hours meter and the Odometer of an ST4 have always been connected, there is almost exactly a 3 miles per hour of operation on a Snow Trac, and a 2 miles per hour of operation on a "Master".
Back to the Transaxel: Courtesy of this additional speed reduction, the equivalent mileage is either 3 times or 4 times what is shown on the Odometer. When you get above the 100 HP level the Dune Buggy guys start beefing up the transaxle's with multiple spider gears and at about 250 HP even these tend to come apart. The ST4 tranny's do tend to Ail from abusive shifting. The Shifting Forks get bent and the shift gets sloppy. In trying to 'Rock' the machine when they get stuck or are trying to pull a truck out of a ditch, the teeth on especially the reverse gear tend to get chipped. I'll have to check as I have a "Report Card" on the last 2 Variators I rebuilt, and I believe we replaced 2nd and 3rd, as well as the syncros. Machines prior to a certain year have no seal where the shift shaft comes out the nose of the transmission and going up steep hills for long periods of time allowed tranny oil to come out and run down the floor matt, making a big mess!When rebuilding one of these the nose cone can be replaced with a new style that has a built in seal. Even if you retro fit an ST4 with a 100 HP engine and use it to groom (you know, push a big plow blade while pulling a roller) I doubt the tranny will fail or even give trouble. There is normally just a couple quarts of 80 or 90 Weight Hypoid gear Oil in a VW Tranny. ST4 Transaxel's/Variator requires slightly more, 7 Quarts! If you run one dry it usually wipes out the input shaft bearings and you may need a new case. I don't recomend that.
Back to the Transaxel: Courtesy of this additional speed reduction, the equivalent mileage is either 3 times or 4 times what is shown on the Odometer. When you get above the 100 HP level the Dune Buggy guys start beefing up the transaxle's with multiple spider gears and at about 250 HP even these tend to come apart. The ST4 tranny's do tend to Ail from abusive shifting. The Shifting Forks get bent and the shift gets sloppy. In trying to 'Rock' the machine when they get stuck or are trying to pull a truck out of a ditch, the teeth on especially the reverse gear tend to get chipped. I'll have to check as I have a "Report Card" on the last 2 Variators I rebuilt, and I believe we replaced 2nd and 3rd, as well as the syncros. Machines prior to a certain year have no seal where the shift shaft comes out the nose of the transmission and going up steep hills for long periods of time allowed tranny oil to come out and run down the floor matt, making a big mess!When rebuilding one of these the nose cone can be replaced with a new style that has a built in seal. Even if you retro fit an ST4 with a 100 HP engine and use it to groom (you know, push a big plow blade while pulling a roller) I doubt the tranny will fail or even give trouble. There is normally just a couple quarts of 80 or 90 Weight Hypoid gear Oil in a VW Tranny. ST4 Transaxel's/Variator requires slightly more, 7 Quarts! If you run one dry it usually wipes out the input shaft bearings and you may need a new case. I don't recomend that.
Lyndon
Bronze Member
More Transaxel: Lots of different ratios are available aftermarket. Some guy's in California and Hawaii were interested in ST4's and contacted me in trying to locate one some years back. They ran a specialty business that fitted VW and Porsche Tranny's with different ratios. The Ring gear is reversable in an VW Tranny and one way it is 4 forward gears and one reverse, the other it's 4 reverse with one forward. The latter way is correct for an ST4 as the engine and tranny are in backwards from VW's original design layout. Beside the difference in ratios I never noticed any significant difference in VW and Porsche Tranny's, as far as how wide the gears were and beefy the bearings are. Physically they hardly change size from the late 50's on into the 70's. An ST4 always has an engine and tranny that are one year older than the Machine itself. If your machine has a 63 manufacture date, as determined from the serial number/year of manufacturer chart, then the engine and tranny will most likely be 62. Westermaskiner bought all of VW's "Hand Me Down" stuff, the left overs from the last year of production. This accounts for all the Bizare year parts on a Machine. My 63 had from the factory: War Issue Steering Wheel (36-44), 46 Bug Tail lights, 56 Bus Wing Window nobs, a early 50's Porsche turn signal switch, a 62 engine, and a mismatch of VW Brake parts.