Hi all, I have a '72 Riviera GS that's currently at the shop getting a Gear Vendors unit installed. While there, the tech noted the trans is slipping and a silvery sheen to the transmission fluid. I haven't had a chance to verify that for myself, and hadn't noted the transmission slipping at all. It's possible, as I did spend a fair bit (all the time) power braking the car at the drag strip the one time I took it this past year. (It started super hard, due to an original battery cable that was far past its pull date, so rather than have the car no crank, I just idled it in the lanes, with my foot on the brake. I figure I put a LOT of heat into it that way. Oops, but I never noticed after any sort of slippage or burnt smell from the transmission fluid.). I have two transmissions in the garage. ST400 (Switch Pitch) TH 400 out of a non GS '72 Riviera The goal for the GS is to be more and better in every respect than stock, while retaining every bit of stock appeal. I love the smooth idle, and based on my trap speed, I'm putting down 235hp to the rear wheels. I'm not looking to drive the quickest Boattail, just something quicker than a stocker. Should I rebuild the SP with the '72 Riviera output shaft, or should I rebuild the trans that's currently in the GS, or should I just rebuild the TH400 and let the SP go to the next guy who will benefit from it? I don't want to spend a lot of time micromanaging the car's performance, I'm looking for a seamless driving experience over additional driver engagement that nets me an extra 0.1 or 0.2 in the 1/4. Thanks for your thoughts and input. Nathan
I would skip the switch pitch, spend the $ on a custom torque converter and you will get a great launch at the track with minimal slippage up top.
I agree with with Sean, the sp is a cool part, but unless you have the converter and the switch pod its not seemless and automatic. I'd get a good converter....lots of ppl are very happy with the unit JW from tri shield makes for them......and go enjoy with better cruiser and better play
One of my favorite parts about switch-pitch is being able to run a tight low-stall, but having the converter slip at stop lights (via the brake light switch) in high-stall. It "pushes" the car a lot less, which makes for a nicer driving experience. If you are more interested in track performance, then skip the switch-pitch. But for street driving, they're a wonderful thing. -Bob C.
Yeah Bob, my 67 Riv GS idles at 500-550 and in high stall stays still at a light in high stall with foot off brake. I have SP on a toggle switch and put in low stall and car slowly starts moving....
x3. Especially handy for an engine like mine with lots of cam (TA 294-04F, previously TA 308S). I still use the factory idle switch, which energizes high stall whenever the throttle is closed, making stoplight idle very manageable. As soon as I tip into the throttle, it goes to low stall immediately...unless I have my thumb on the momentary switch mounted on the column shifter... Devon
When I had my switch Pitch, I used Bruce Roe's electronic control box. It utilizes 3 different timers, and hooks to the brake switch, downshift switch, and engine vacuum. I had Bruce modify the box so that it mimicked the factory function. High stall with brake on, Low stall off idle, and back to high stall below 4.5" of vacuum. It worked great. It had a Drag Racing mode, and manual control. Read this thread, https://www.v8buick.com/index.php?t...es-electronic-controller.190075/#post-1663402
If I had a rebuilt turbo 400 sitting in front of me and a rebuilt switch pitch 400 I choose the switch pitch every time. It's a pretty versatile transmission but if you're using it for bracket racing and consistency is required a regular turbo 400 might be a better option