Anyone see the Hemming Muscle Machines that just came out. They have an article on Bill Baylis and Baylis claims that the Stage 1 BB trans came with a 2.75 first gear rather than a 2.48. I say BS! I've had a few Stage 1 and I don't think so! Also, I don't think the 2.75 planetary set even existed in 1970. Didn't it come from a later T-125 or something? Mark Diconti? You there, I'm sure you know. Bruce BQUICK
Bruce, To the best of my knowledge, only the 2.48 gearset was available in a Buick. All the parts listings and literature I have show only one planetary setup. Supposedly there were GM trucks that used the lower gearset, but I would have to check and see when it first came out. 1969 or 70 sounds too early to me. I have pulled apart at least 3 100% original 70 BB trannys (one was Carl Rychlik's) and they did not have anything different than a standard TH400 in the way of gearsets. So, I think someone is mistaken in what they think was in it. Mark
Didn't the original Stage 1 BB trans have some tricks done to them? Atleast some sorta shift improvement change (ball checks). I drove in an original old lady 1970 GS Stage 1 back in the mid eighties and it "chirpped" the tires going into second. That car was a real bear when hammering it at 30 mph and it down shifted into first. spun the tires, ran it up to about 5000 rpm and "chirpped" them into second...................sweet. That was a triple brown hard top Stage 1 hard top.......nice car. Lon
Hi Guys, Back in June of 1985 I bought my first GS455, not a Stage1 car though. It was a '72 model that was 100% stock except for the Firestone Super Stock tires and a new battery. This car had 41,000 miles on it and had all records of everything that had ever been done to it since delivery. It was equipted with the non-Stage1 TH400 and 3.08 geared "one-wheel wonder". The part that would literally freak everyone (including myself the first time I took it for a ride) that I ever took for a ride was that the tires would consistantly break loose hard at the second-to-third shift at 85-87mph but would only occasionally chirp them at the first-to-second shift! o No: Man....do I miss that car! :ball: Lon.....one of the things I've read is that the BB Stage1 400's had a 6 clutch pack compared to the standard 400's 5 clutch pack. I'm sure the valve bodies had different calibration set-ups also.
The 70 BB Stage 1 was unique. The later valve bodies were not setup like it, though close. Not all 70 Stage 1 BB's had the 6 clutch drum, it depended on the build date as it was used after a certain point. A lot of 70 BA's had the 6 clutch drum too. The BB's used a different direct piston which improved the 3 gear shift. The 70 BA valve body is VERY close in design to the 70 BB and only a spring in the 1-2 accumulator valve needs to be removed to make it the same. No waved steel plates were used in the 2nd and 3rd gear clutch packs on the Stage 1 trans, and the 3rd gear valve body accumulator spring was softer to firm up the shift. The governor was setup to shift at approx. 5500 rpm and was specific to 1970 BB only (some model of Pontiac and maybe Olds used it too). Later governors were ok, but closer to 5200 rpm. The valve body separator plate has larger holes in places to increase pressure to the clutches. Am pretty sure that 70 was by itself and 71-72 was different. Would have to check to be sure. One of these days, I will take pics with my digital camera and show what was different and WHY it made the BB trans special. It would be nice to have the info all in one spot for reference. One last point, there is no need to go out and spend a fortune on a 70 or 71-72 BB trans. In my opinion, a properly setup TH400 can be built to come VERY close. Mark
The only variations in Hydramatic-built gearsets were helical and straight-cut gears. Both were the same ratios. The straight-cut sets were only used in truck & school bus applications as they were too noisy for cars. Their advantage comes from the fact that there is no thrust load generated by the tooth form which is easier on washers under load.
Remember that's what the writer said Baylis said, I've seen more mistakes by the writers interpretation, than the subjects mistakes in car magazines than in most any other periodicals.
