Here's a wierd one. Sitting at a light the car tries to "surge" forward. The idle is constant and the surging stops in neutral, rules out the engine. Happens in any gear, high or low stall makes no difference. I've got a fresh rebuild on my Switch Pitch 400, and a new 464 powering it. The 400 is built with 36-element dogbone sprags, Red Devil clutches, short tail shaft, adjustable vaccum modulator, and a shift kit. Running a PAE 4000 SP converter. I'm thinking this rebuild is toast, like a band clutch is catching or something...any suggestions?
I would almost say that you MIGHT have got a defective converter. But I am no expert. Ill be watching this tread for details from the experienced.
Sounds like a converter problem.........with the key on and the motor not running, try listening for the solenoid clicking. If it does, then try doing a brake torque and compare the stall speed with the power connected and with the power disconnected. The 2 speeds should be at least 400 rpm different, depending how much stall the converter is designed for. :bglasses:
Sounds to me like you only have low stall. Low stall on that converter, if memory serves, is 1400 RPM. A cammed motor that wants to idle at 800 or so, will want to push in low stall. When you select high stall, when idling in drive, the tach should jump at least 200 RPM. Check for 12 volts at the horizontal tang of the electrical connector(drivers side of trans), and listen for a click from the solenoid(motor off, key in run position, and high stall selected)
Thanks Guys! Well, I've been driving in street form (low stall only) and didn't even think to check high stall. :dou: I got a click from the solenoid, and it does have 12V at pin. Thing is, she won't go into high stall anymore! Only launches at about 2000 rpm. If I'm still getting the click this makes me think the solenoid is working but sticking half open. Thoughts?
I'll bet it's the converter. Once my downshift solenoid became sticky and I had to take it apart and clean it out, but I've never had any problems with the pitch solenoid so far. I suppose that one could get sludged up too. Problem is, you have to take the tranny out to get to it.........it's inside the front pump housing I think.....may as well change the converter if you have any doubts. :bglasses:
I agree, change the converter, it's the easiest thing relatively speaking. Who rebuilt the transmission? There are certain differences that are important when rebuilding a SP. Don't know the specifics, but I'm sure JW or JB can help.
The rebuild was done locally by a reputable builder. the converter is a brand new PAE 4000 stall. the input staft was correct when I went over the rebuild, could they have screwed up the pump enough that the SP wouldn't work?
There is an orifice that needs to be blocked, or reduced in size. Otherwise the SP doesn't work. I believe JW uses the end of a glass fuse to block it off. I'm just going from what I recall. Either pm JW or JB, or even dcm422(Mark Deconti). They could give you specifics.
I'm no expert here, but I had a problem in my SP where it would be in high stall at the line, then as soon as I hit the throttle the convertor would go into low stall. It was unmistakable. It turned out that when my tranny was rebuilt, the internal pressures were too high, and the WOT situation drove the pressure up so high that it over-rode the solenoid and went into low-stall. My tranny rebuilder was able to straighten it out using the pressure gauge and his expertise (of which I obviously have none). -Bob Cunningham
Hmmm, both are good thoughts. I guess I need to dig out Ron Sessions book and start looking for culprits...
Ok - so it only took 6 years to sort out the problem. This particular trans is apart right now (I swapped it in 2006 as it was utter crap). Pump gears are in backwards. :blast: Explains the surging and the VP activation problem.
I don't know if it's a good thing or a bad thing, Clint. Since this thread we've learned about the shoddy redesign/rework that went into the PAE variable pitch converters. There are some who have had good luck, and some who have lost transmissions because the converter self-destructed. More here: http://www.v8buick.com/showthread.php?t=114558 and http://www.cadillacpower.com/forum/viewtopic.php?f=2&t=9394 I have a copy of the Cadillac Power Forum thread with interior shots of one of the failed PAE converters if you need more detail. Devon
++++++++++++++++++++++++++++++++++++++ I'd suspect the converter first, but also check the STATOR VALVE in the pump body. You can do an air test as shown in my PHOTOBUCKET, sub-album BUILD A SWITCH TRANSMISSION, picture 15. Bruce Roe http://s93.photobucket.com/albums/l71/bcroe/ (that is a lower case "L"71, not an upper case "i"71) click on a Sub-Album click on a picture to enlarge
...hey the stator valve is a good idea! Ah - the converter's been ruled out. It behaves the same with: 1. A locally rebuilt converter 2. a PAE converter 3. a Trishield converter ...so...checking the orifice plug and the stator valve now.
