I know when the shifter is put in low the 1-2 and 2-3 shift points raise to a higher rpm. What happens when the shifter is dropped into second? Reason: when I have it in drive the 1-2 shift happens at the perfect point and the 2-3 happens too soon. When I drop it into low the motor hits the rev limiter before the 1-2 shift. I want to put the shifter in second, have the 1-2 shift like it is now but shift 2-3 when it needs it. Thanks
Most shift kits take out the "shifter overide" function from the factory. This means it will downshift but not upshift from the gear you have selected. It sounds like you need to do some work on the governer to get them correct. Do you know what has been done to this trany over the years? I talked to Transgo about a year ago and they told me to really dial one in I had to measure the shift valves and call them and they could walk me through the steps on this. Good luck Mike
I put in a TCI shift kit but thought it left the overide intact. My sister in law drives the car and it's better for her to leave it in drive and let it shift a little low. When I drive it I'd drop it in low let it shift itself into second (about 500 rpm higher than drive) then do the 2-3 shift myself. After a torque convertor change if I use low it hits the rev limter. In drive 1-2 is perfect but the 2-3 shift comes too soon. I'm hoping I can just put the shifter in 2nd, let the 1-2 shift happen just like it does in drive, then do the 2-3 shift myself. I've played with the governor weights and springs but I've never been able to get the 2-3 shift to happen at the same rpm 1-2 happens. It's always a lot lower.
Doug, It isn't a Switch Pitch is it? And are we talking about Wide Open Throttle shift points? I had that problem with the 2-3 shift point being a lot lower than the 1-2. It turned out that the SP valve bodies were like that on purpose. I ended up changing to a 1971 BC valve body and playing with the Governor to get my 5500 and 5400 shift points. BTW, shifting 2-3 yourself will eventually wear out one of the bands in the THM 400. Manually shifting 2-3 accomplishes the shift in a different way that wears a band in the transmission. I got that straight from Mark DeConti, our N.E. THM400 authority.
Thanks Larry, I remember reading that somewhere but I can't find it now. I'm giving up on trying to get the governor to hold it in second gear. Everything I've tried has failed. When racing in D it hits second then right into third. In Columbus I dropped it into second and shifted it myself into third and it worked well. Nice and crisp shift. When the car ran 11.70's it worked fine, 10.90's and won't stay in second.o No:
You may need to change the valve body. I had the same problem with my SP valve body. I switched it to a valve body from a 1971 BC transmission, and that enabled me to set up my governor. Mark explains it here: http://www.buickperformance.com/SPTrans.htm
Sorry Doug, I don't mean to hijack your thread but I have a similar issue. Larry, I took my 71 GS to the track last night. I have the same issue. The car shifts in to third gear way to soon. Yes I'm running a switch pitch converter as well. So if I understand your post correctly, playing and experimenting with the governor won't delay my sec to third gear shift to redline ? I noticed the transmission in my car is coded "BT" which if I'm not mistaken maybe out of a Riviera. So to get my sec to third gear shift at the correct rpm ( full throttle ) I have to use a different valve body ? Which one in particular would I need? Thanks, John B.
********************************************** Along with the BT, should be the year of the trans. If its an original 65-67 switch pitch, you may be advised to get a later valve body. Bruce Roe
:laugh: I have a 1967 BT trans in my car, and I had the same issue. If you read the link I posted, it explains why. Basically, Buick intended for the car to accelerate on the converter rather than the gears when it comes to the SP transmissions. As a result, the valve body calibrations in a SP transmission tend to keep the transmission in high gear and get it in sooner. I played with my governor and got my 1-2 in at 5500, never checking the 2-3 shift. At the track, 1-2 at 5500, and immediately into 3rd. The SP valvebody doesn't have a 3-2 valve, so no part throttle kickdown. You have to floor it to get it to kick down. Sound familiar? The solution is to swap in a 1970 or later valvebody. I used a 1971 BC valve body. That solved my issue. Read the linked article I posted.
i would try a heavier spring on the 2-3 shift valve. the governer will only help for a 1-2 shift and the modulator will only raise or lower all the shift points. using a heavier spring on the 2-3 shift valve will allow psi to raise before stroking the valve and applying the shift.
