Found a 66 st400 from Riv I want to swap into my GS. Is it the there a specific rebuild kit for the TH400 SP trans? I will be using my ST300 Torque converter. Anyone know a reliable rebuilder in Bucks County, PA area? Any sage advice for this swap? Thanks
Following, and also interested if anyone has used this crossmember in stock frame locations: https://crossmembers.com/product/19...x-crossmember-400-convertible-or-boxed-frame/
Same rebuild kit as any 400. The difference for the SP is the front pump, input shaft, and the converter.
If you're looking for the correct floor shifter for your ST 400, I have one for sale...........http://www.v8buick.com/index.php?threads/67-gs-400-st400-floor-shifter.338582/
The 1966 ST400 is a Switch Pitch, and the ST300 was Switch Pitch from 1964-1967. The TC will work as a direct replacement, and will be very beneficial, as the stall speed will be higher and the mass lower, so spin up will be quicker. I sent both my ST300 SP torque converter in for rebuild and my ST400 SP transmission to Jim Weiss for rebuild. Given that most tranny shops have little experience with the Switch Pitch, and some are very negatively biased against eh SP feature (because they are clueless of its capability), I would rather someone who "speaks Buick" as a first language deal with my stuff. If I had the means and tools to do the work myself, I would, but will gladly pay someone with the expertise and resources to do this for me. The total is about $1500, but well worth spending half that and getting something that fails, netting you nothing for half, and you still have to spend more to get fixed. (NH Ronnie, I think Jim also has TCs for the BBB/ST400) jmho.
Buick called their "300 and 400" series transmissions "Super Turbine" to keep the "Turbine" in the name as a follow on to the "DynaFlow Dual Turbine", because "Turbine" was "cool" back in the day of jet aircraft. Later, they started referring to the transmission as the TH-400. But the ST-300 and ST-400 could have been both Switch Pitch and Fixed stator torque converters. There are ST-300 and ST400 transmissions that were not Switch Pitch. The "ST" has nothing to do with a transmission having the Switch Pitch, it was year specific. 1964-1967 for the ST300, and 1965-1967 for the ST400.
A board member had recommended a trans shop in Doylestown. Maybe he'll reply with more info. It's on Main street on the south end. You'll need to make some crossmember brackets to weld onto the frame since the ST400 trans is longer. Driveshaft needs to be shortened. Shifter will need to be modified to accommodate the extra position (D, 2, 1) instead of (D, L). You can buy a shifter mod kit from Shiftworks.
Thanks Walt. I did talk to talk to John at the Trans Shop. Want to make sure I have my "ducks in a row" before committing. Is there a good TH400 kit you recommend? TransGo shift kit? I do run the car at the strip now and then. Also looks like SC208-2 is the Shiftworks kit.
Dave, here's the post that recommended them. There isn't a lot of info tho: http://v8buick.com/index.php?threads/honest-trans-shop-in-pa.329109/ Here's a thread on the cost for a rebuild: http://v8buick.com/index.php?threads/average-th400-rebuild-cost.338324/page-2
Just make sure that whoever does the rebuild, is completely on board that the TH400 will REMAIN SWITCH PITCH. Shops are inclined to just throw that feature away and put in later fixed parts. Use your converter over if the miles are not too high for a stock engine. I have done that swap, also TH200 and TH350, using a short tail TH400. In every case, using the shortest TH400 yoke (which has to be changed anyway) allowed me to retain the original drive shaft. Rear support moves back almost 7 inches. A 350 shift linkage works on a 400, but I find a 200 does not, check yours out. Here is one I modified to solve the problem, clamped the extra arm on for trials, then welded it. The 400 rebuilds are basically the same, but you need an extra 1 inch steel seal for the input shaft. If the pair of 1 inch bushings for the input shaft are changed (I usually do not), note that one is shorter than later TH400s. If a full length bushing is put in, it will block the oil passage (very, very bad). Bruce Roe
Hi all Want to restart this thread. Found a rebuilt 65 code “BJ” ST400 on craigslist. Has an aftermarket pan and looks like a red stripe modulator. Some questions. The torque converter that came with the trans looks like a switch pitch to me. Can anyone identify? Was originally intending to keep my ST300 TC and flexplate but it looks almost new, if I use the new TC should I stick with the current flexplate? Also is the change to my 2 spd shifter just a new detent plate? Same lever, rod, etc? Thanks want to get ready for spring if it ever stops snowing here in PA
AFAIK, a fixed pitch converter won't fit on a switch pitch input shaft. The stator splines on the SP input shaft are 1/2 the width of fixed pitch stator splines. The matching splines in the SP converter are deep enough where you can't reach them with your finger. Jim Weise explains that in that thread I linked for you. If there is nothing wrong with your flex plate, reuse it I say. You always take a small risk that a new flex plate might have a balance issue. The Chassis manual has a procedure to deal with that, but why take that chance? New detent plate in the shifter I would think.
