Since I am still waiting for the machine shop to finish work on the engine for my '65 Riviera, I have decided to rebuild the transmission. I haven't looked at the transmission since I pulled it with the engine. The car barely ran when I bought it, so I could not determine the condition of the transmission. I did take it for a brief ride down my street and it would not shift out of first gear. After I pulled it, I realized the vacuum modulator was not hooked up, so that might have had something to do with it. It also leaked like crazy; anytime I topped off the fluid I would find a puddle the next day. Either way, it's getting rebuilt while it is out. When I put the trans on my workbench I noticed it did not have the heel print pan associated with a switch pitch trans which originally came with the car. I looked at the tag on the case which showed BR 65, which I believe is the code for a '65 Riviera with a 401, which matches the car. I looked at the input shaft; it appears to be a switch pitch shaft. I pulled the pan and found a flat filter. Now I am thinking this is the original case with the valve body from a later model trans. There is a casting number on the valve body of 8623568. Can I use that number to determine what I have inside the case? Is there any other things I can use to identify this as a switch pitch trans? Here are some pics from what I looked at tonight Thanks Doug
if it wont shift out of first you have either a modulater problem or a governer problem. sorry i cant help you with the switch pitch problem.. does it neutral when it tries to go to 2 or dont do anything at all. have you tried going from m1 to m2? ---------- Post added at 09:36 PM ---------- Previous post was at 09:35 PM ---------- have the directs dual fed and switch to a turbo 350 rear thrust bearing and get a 4l80 direct drum with the good sprag and you should be set with a cruiser.
The variable pitch function doesn't rely on the valve body, so don't worry about that. If you have a later valve body and pan, they may have been installed because of the difficulty in getting an original filter. The later flat filters have to have the retaining bolt hole threaded, some of the old ST400 bodies don't, so that's at least one reason a later valve body could've been installed. Besides the pump being a variable pitch unit, the wire running forward from the case plug is a good sign that the stator solenoid is connected. Non-VP transmissions won't have this. Devon
If the modulator wasn't connected, that would cause it not to shift out of 1st. There are benefits to a later valve body besides easier filter availability. You gain a part throttle kick down as well as the ability to get a higher RPM shift to 3rd gear. I have a 1971 BC valvebody in my 67 BT switch pitch transmission. Read more here, http://www.buickperformanceclub.com/SPTrans.htm
Lonnie, it did not go neutral, it just stayed in first gear I am not disappointed by the later VB in the trans, as I am aware it has some benefits. It was more of a surprise. Hopefully, whoever did the work was competent. Once I get the oil pump off, I will know for sure whether it is a switch pitch I was primarily concerned with identifying what VB it is or whether it was the original VB modified for the later filter. I always like to know what I have before tearing it apart and purchasing parts. Anyone know if the casting number on the VB can be used to identify the year/model? Thanks Doug
No, I never floored it to see if it would shift. The engine was shot and I was concerned that it would let go and cause irreparable damage. One ride up and down the block and one long smoky burnout in the driveway and the car was disassembled.
Doug, It's a switch pitch for sure. I can tell that just looking at the input shaft. The stator splines are about 1/2" vs. the fixed pitch's 1" stator splines. Have a look at the pictures in this thread, http://www.v8buick.com/showthread.php?143723-VP-converter-Trans-visual-ID-guide Don't know about the valve body casting numbers, but the only way to convert the SP valve body over to later filter would be to drill and tap the threads for the bolt to hold the filter. It's most likely a later valve body.
Thanks Larry, I saw the splines as well and figured it was a SP. Just wanted someone else to confirm. I did notice the bolt holding the filter on is somewhat loose in its threads which is why I thought someone had potentially drilled and taped the original VB for the flat filter. I looked down the bolt hole and it looks factory, so it is most likely a later model VB. I also took a good look at the valve body and if I am understanding the differences over the years, it looks like this VB has a 3-2 valve, which would not have been present on my original VB Yes, I plan on rebuilding it myself. This is not the first auto trans I have done, but it is the first ST400 I will have done and it's been a while since my last trans rebuild; so I am doing a little reading before diving into it. Anyone recommend a good rebuilding kit or a vendor? I was reading an older thread on rebuilding the ST400 and I would like to perform some upgrades as well,, so I am not looking to perform a stock rebuild. Thanks
That SP trans has just what I do: new style pan, filter, and valve body. The original valve body CAN be drilled & tapped for the new filter retainer bolt. But the factory milled a flat for the bolt; I wouldn't expect that on a field mod. If your trans shows little wear, you might just renew it with a $30 seal kit. It replaces all the rubber, have bought them from a couple suppliers. good luck, Bruce Roe
