Governor info

Discussion in 'The "Juice Box"' started by David Butts, Jun 24, 2010.

  1. David Butts

    David Butts Gold Level Contributor

    Does anyone have the part numbers for the governor used in the BB trannys or the HP goverenor that used to be available from GM?

    Since the goverenor is a hypersensitive piece in relation to rpm's and the BB tranny were usually in cars with 3.42 rears or higher I'm thinking that would be a better part to start out with than a passenger car part that was originally installed in a car with a 2.56 rear.

    I have several Governors here and one thing I've noticed is not all the primary weights(the large outer ones) are the same, They look similar but weigh different amounts and that affects the 1-2 part throttle shift from what I hear. Correct me if I'm wrong. Please:confused:

    Also I'm familiar with all of the grinding of the smaller inboard weights and so on but that only affects WOT shifts and I'm trying to dial in a part throttle 1-2 shift aswell.

    I'm sure this subject has been covered in depth in the past but I think there are others that may be interested in a rehash too. I am:eek2:

    Thanks in advance
    matt68gs400 likes this.
  2. David Butts

    David Butts Gold Level Contributor

    Been tinkering and I still have a too early 1-2 shift and maybe a little high full throttle upshift in both gears but it's heading in the right direction. I have parts of two different B&M calibration kits and springs out the :moonu: so it's only time.

    Next on the list is lightening the primary weights. :Smarty:
  3. fireball

    fireball Well-Known Member

    Check this link out. It is for switch pitch tran's but goes into explaining about 1-2 shift points. It may give you some info.

    Look into what trans you have as in year/model (70 BA, 73 BC, 71 BS etc.)
    as each model has a differently calibrated valve body. The 70 BB governor is p/n 8623898 but is next to impossible to find.
    Just about all TH400 governors can be made similar, but shift points depend on the valves explained in the link.
    Hope this helps.

    BRUCE ROE Well-Known Member

    An adjustable vacuum modulator can also have some effect. Bruce Roe
  5. Jim Jones

    Jim Jones Wretched Excess

    OK here goes. Part numbers from my 1973 parts manual. I will start at 1969 as this was the first year of Stage 1 production. (Buick TH-400 only, complete governor).

    8623852 69-70 except 4600
    8623898 69-70 4600 Stage 1
    8627442 70 GS455 except Stage 1 & 9000 GS

    8627443 71 GS455 & Stage 1 & 9000 GS
    8627441 71 50-60-80-9000 except 9000 GS

    NOTE: 1972 1st type has no flat spot on governor sleeve, 2nd type has flat spot ground on governor sleeve. (appearantly part was changed, but part number was retained).

    8627443 72 3437-67 (455 eng.) & 9000 GS 1st type
    8627441 72 50-60-80-9000 except 9000 GS 1st type
    8627443 72 3437-67 (455 eng.) & 9000 GS 2nd type
    8627441 72 50-60-80-9000 except 9000 GS 2nd type
    8627445 72 transmission coded BK

    8627595 73 transmission coded BC
    8627443 73 transmissions coded BB-BS-BT-BU

    Jim J
    matt68gs400 likes this.
  6. Jim Weise

    Jim Weise 1000+HP

    Dave, here's the weights from an original 70 BB Governor

    Outer- 1 is 42 Grams, 1 is 43 Grams

    Inner- One is 8 grams, one is 9 grams

    Springs- Free length is .950, there are 9 coils, with a wire diameter of

    This is the governor that all my Level 2 transmissions leave with, plus I send the springs/weights from the kit with the trans, so the customer can fine tune if he wants. I can't recall ever getting any phone calls or emails from customers who were fooling with the weights, so either they are smart cookies and don't need any help from me, or they are happy with the shift points.

    IN my testing, that governor will upshift 1-2 at about 5300, and 2-3 at right around 5000, with most 68 -74 Buick Valve body calibrations at WOT. Proper operation of the detent switch and solenoid are key here for that to happen. Most GS's, even if they have the switch in place on the accelerator pedal, don't work properly. An old trick to make sure the switch engauges, and to get it a little sooner, is to use a piece of rubber hose on the activation pin of the switch, to get it to hit the pedal rod a bit sooner, and make sure it travels far enough. I would say that fully half of the cars here that I have installed the trans in here, or have worked on for other reasons, won't travel the switch far enough to activate the detent system.

    This is fine for that occasional full throttle blast, although I always suggest that my customers manually shift the trans, for drag strip use, especially over 500 HP. Internal trans pressures are increased, for greater holding power on the clutches, as well as there are bands holding the elements in low and second manual range, vs what's going on it 1st and 2nd, Drive range.

    My Level 2 trans has provisions in the valve body, which allow complete manual control of 1st gear.

    Part throttle shifting is controlled by regulating Detent pressure, this is done by using a red-stripe small can modulator, and as Bruce mentioned, adjusting the preload spring thru the hose nipple. I have found that the pink modulator valve spring that comes with the Trans Go shift kits, gives more control of the modulator pressure.

    What your after is a smooth transition, so the trans does not shift too early, thus not taking full advantage of the torque available, or shift too late, causing a "lag" feeling. Exact calibration on that will change from car to car, as gearing and engine output are the biggest factors here.

    With a good setup 400, it should be fairly difficult to even notice the part throttle shifts. As Gil Younger (trans go founder) says, When a good shift happens, the car speeds up, and the engine slows down, and there really is not alot else to talk about.

    I find this especially true in GS's with 3.23 or numerically lower gearing.

    matt68gs400 likes this.
  7. David Butts

    David Butts Gold Level Contributor

    Thanks for the info guys and the weights specially Jim. Over the weekend I weighed all of the outer and inner weights I had on hand including the leftovers from a B&M kit and for the time being I put a combination of stock GM parts back in the car just for testing/reference purposes.

    I have some stock outers that are solid and a couple pairs with large holes and it is those with the large holes that give the latest part throttle 1-2 shifts so I'll use my tremendous powers of deduction:rolleyes: to ascertain that it is indeed the outers that have the largest effect on the part throttle shift since they have the heaviest mass and would swing out earlier.

    When I installed the full outers with no other changes the trans shifts 1-2 almost as soon as the car moves. :error: :error: :error: Inversely, When no other changes were made but to throw in the windowed weights the part throttle shifts were later.:TU: :TU: :TU:

    I googled the high perf GM governors and found a picture of one that was supposedly in the late 60's Vettes and Camaros and they had the outer weights with almost square looking holes or almost all of the outer weights gone.

    I want to get the street manners of the trans to where it shifts almost as if I would a manual trans during normal driving and then I'll change the inners and springs to get the WOT shifts where I want them.

    Thanks again everyone. If knowledge is power? I'm pretty weak
  8. David Butts

    David Butts Gold Level Contributor

    Wow, Can't believe this thread was started two years ago. I was just Googling some transmission stuff and this link came up. :TU: and no I haven't done a thing to the tranny since my last post here proving I really do put things off forever:confused:. Buuut I am getting ready to delve back in to the governor tuning on mine and a good friends Buicks. It was actualy he who asked me last weekend at a cruise in if I had ever gotten mine working like I had wanted? The weather here is cooling off a little so once some parts I ordered come in I'll get back to working on it and hopefully update here like I said I would. two years ago?:Dou:
  9. David Butts

    David Butts Gold Level Contributor

    Here's a little recent update for anyone interested, My search for info on the GM governors uncovered the facts that there was a whole bunch of different part #'s used in the different trans/combos and that hardly none(I couldn'd find any, neither could a buddy who works at a dealer parts dept) of the parts such as weights and or springs were available as an orderable service replacement part. you either got the whole governor or nothing excluding the driven gear. Buuut all the governors (250,350,400,2004r and 700r) used the same governer housing/body/valve plunger with only the gears and the top cover being different excluding some weird larger head versions I saw.

    As I mentioned before I was really trying to get my part throttle shifts in drive to a higher rpm/speed than they currently were. Just like a bunch of you on here, I had messed with the inner weights and springs a ton and on several transmissions had gotten them to full throttle shift in drive acceptably but part throttle was always much to low after a rear gear change.

    But a real tinkerer is never done tinkering so I kept at it. What I ended up getting was a 700r governor that was supposedly for a Corvette/Camaro application. It had the outer weights that were almost non-existant so if my thoughts were that the outers controled part throttle shifts or atleast the combined lighter weights would raise the pt shift I was game. Fortunately getting at my governor in the 400 trans is a 4 bolt 1 minute opperation compared to the much harder 350 cover(been there done that several times too). I bought a small digital scale so I could acurately weigh the weights in grams and since JW provided some good reference in an earlier post I was off.

    Hopefully the pics load in order, I had to upload my phone pics so sorry for the quality if not clear enough.

    What I did was instead of changing the gear and top cover on the 700 gov, I just swapped all the weights and springs to my current 400 gov and without a doubt. It did raise the pt 1-2 and 2-3 shifts virtually to where I wanted them. Havent done an exact mph/rpm test yet and have not tried a full throttle blast yet either although the setup was in the car in my smokey de tires video under my signature.

    Attached Files:

  10. David Butts

    David Butts Gold Level Contributor

    A spring is a spring, Or is it? I recently discovered that all springs that come with the various aftermarket manufacturers governor recalibration kits as well as OEM originals are not the same. I have made the mistake of assuming that springs of a certain color were the same spring rate but I was Wrong. Very wrong. Over the years I've amassed an assortment of springs and had grouped them by colors which I mistakenly took for granted. I've even given out bad info on more than one occasion since in one instance I claimed that higher rate springs produced later part throttle shifts and that was based on my tests where I had installed a spring, That by color standards was a higher rate spring but in reality it was a much lighter spring than others of the same color I had. It wasn't until I really started looking at how the springs are as installed in use in the governor and started checking spring to spring with a simple tool I made. That wasn't enough though as checking springs at or near their free length still gave misleading results. Once I measured the actual area where the springs are in use between the outer and inner weights(measured less than .500)I realized that springs of nearly the same tension were totally different in compression. What I needed to do was try to simulate the way the governor worked with the hydraulic pressure of the fluid acting on the plunger or valve itself. Since out of the transmission there is not a home garage friendly way of doing that hydraulicly, I found a small spring that would simulate that pressure to allow me to see and feel somewhat how the governor works. At least mechanically. I placed the spring, actually a heavy rate front suspension spring used in competition rc cars which I also have a bunch of. Inside a gov(see pic) In use the gov valve is pressurized against the tabs on the inner weights causing them and the outers to be held in against the body of the gov I'll call that at rest. Once spinning the outer heavier weights swing out first which has no effect on the gov valve unless very heavy springs are used causing the inners to swing out early creating very early shifts. Now heres where the findings got strange. Some springs of even light tension have enough coils so that they actually coil bind or stack causing the inner weights to be mechanically swung out once the outers got to a certain distance from rest. Again causing early shifts. Since some of the original springs I had did this it could be that the engineers intentionally used that to dial in the shift points on certain uses. When springs of light enough tension and coil count are used it is truly centrifugal force at a given rpm which causes the movement. As stated here and elsewhere, There are several factors that contribute to how a trans shifts such as shift valve springs and internal valveing but the Gov still has a major effect. I got online and Googled miniature spring rate checkers and whoa Nellie I don't have that kind of money. We're talking hundreds and thousands of dollars just to say this spring is of XXX inch pound rate at a specific installed height. DSC00017.JPG DSC00023.JPG DSC00027.JPG DSC00026.JPG DSC00019.JPG DSC00022.JPG DSC00020.JPG DSC00005.JPG DSC00028.JPG DSC00024.JPG

    BRUCE ROE Well-Known Member

    Right, don't spend big money to measure springs. Just push a couple together on a
    1/4" rod. I managed to sort my collection into about a dozen levels, along with
    those in a governor calibrate kit. The other thing is an adjustable vac modulator.
    After that, you have to take the pan off. Bruce Roe

    Attached Files:

  12. David Butts

    David Butts Gold Level Contributor

    Yep Bruce, I'd never spend the $$ for a Spring checker but I was curious as to how much they'd be. Also I should clarify. I had compared almost all the springs I have to one another over the years but there were a few that I had just thrown in with others of the same color without checking and that's what got me this time. The pictures didn't load in order nor did all upload so they really don't make sense with my story. I have never gotten the hang of the forums new look and functionality.

    ---------- Post added at 07:20 PM ---------- Previous post was at 07:12 PM ----------

    Also the pictures from post#10 are only of the newest kit I bought from a local transmission shop. The springs are powdercoated in lieu of the paint that usually falls off or becomes almost unidentifiable quickly of the other aftermarket kits. This one also has some part numbers of actual GM govs for the 700r4 including the Vette, Camaro with 5.7 and the Police Impala with 5.7 complete with inner weight types and factory installed spring colors, Ofcourse they don't correlate to the kit colors but it's still good info to have since most of the governors we use can benefit from the same weight and spring info. I did have to run a 3/32nd drill through several of the weights to get them to fit the included axles correctly. Even though I didn't use the weights. Yet.
  13. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Thanks for all that info!!!

    I am excited to get my switch Pitch Th400 swapped in! I was going to go with my manual vavlebody th400 but I would really like to be able to leave it in drive on the street.

    I will be likely asking you some questions when it comes time to adjust the shift points of my car... My engine was built to handle 7000 RPM however I am setting the rev limited at 6200. Shifts at 6000 should work well at the track.
  14. David Butts

    David Butts Gold Level Contributor

    Just a short video to show where I'm at right now with the part throttle work . This is with the stock GM 700r Corvette/Camaro windowed outer weights and small or narrow tab inner weights(9.7 gms give or take a point)as in the pictures above and the two lightest springs from my new kit which are not the lightest springs I have. This part throttle acceleration only to see if the changes are positive or negative. albeit my part throttle may not be yours since my current converter is so loose it takes quite a bit of throttle to get the car moving as you can hear. By the way, I have a 9.5" converter coming from Jim W. so this slippy slippy tiny little converter will be going away soon. Yipeee

    ---------- Post added at 11:05 AM ---------- Previous post was at 10:55 AM ----------

    First off, apologies for the shaky video but this is the first full throttle in drive(strictly automatic shifts) test of the current governor combo which is the same as the part throttle vid above. I'm getting very close to where I want this thing:Brow:. The 1-2 shift is right at 6000 rpm's and the 2-3 is what looks to be in the 5400-5600 range but I may have lifted just a wee bit since I was coming up on the traffic in front of me very quickly. . I'd like the two shifts to happen at the same rpm but that will probably take changing the springs in the valve body which I may tackle next. Notice also in the vid(if you can)that I have a flat spot or hesitation around 44/4500 and I'll get to that too as this is also the first time I've tried a full wood acceleration with the Holley 870 Street Avenger that's on the car now. May throw on my Double pumper to see if it's carb or something else but that's for another day, thread and drinkering session(and video?)
    Last edited: Dec 24, 2012
  15. low buck Jim

    low buck Jim Well-Known Member

    Thanks Dave for sharing your modifications to your govener! I have the ta 500 hp street cam, 3500 stall 9.5" converter and 373 gears. my car shifts into 2nd then 3rd allmost immedietly.I cant hardly hear or feel the shifts.This thread wii be a great assistance to me as I remedy the issue Thank you very much!!
  16. David Butts

    David Butts Gold Level Contributor

    Jim, That's the same issues I had with mine before I started messing with the governor in this particular transmission. A loose converter will eat up some or most of the shift feel but mine would be in drive almost as the car started moving in light throttle acceleration with almost no shift feel and both shifts happened waaaay to soon in full throttle blasts. As a side note, The trans before I started this work would rarely down shift out of drive at anything over around 40 to 45 mph and if it did it would only to 2nd which was still just causing the convertor to act as a DynaFlow tranny. Not to impressive. By changing only the governor springs the trans will now downshift all the way to 1st(which by the way the original BB Stage1 trans did) and the car actually accelerates. What a novel idea? In the full throttle vid above I was cruising along at about 45 when I matted it. YeeHaw! :3gears:
  17. rmstg2

    rmstg2 Gold Level Contributor

    Thanks for posting the videos. I am also having early shift problems, and will be ordering a governor from JW when I get back from my Christmas vacation.:TU:

    Bob H.

    BRUCE ROE Well-Known Member

    I have a 67 Buick trans that with the pedal floored, would shift at 15 mph. After
    I got done with the governor, it shifted at 55 mph. It probably would help to
    swap on a later valve body & governor as a starting point. Bruce Roe
  19. 72droptop455

    72droptop455 Member

    I have found that using the B&M #4 and #5 weights along with stock GM springs gets you into the 5000-5300 WOT shift points neighborhood with a TH400,FWIW
  20. David Butts

    David Butts Gold Level Contributor

    Not Governor work this time but last saturday I swapped converters to a used one I picked up from Jim Weise. Oh my goodness! What a difference that made. I've never driven this car with the 455/T400 combo with any other converter than the really loose one That was in it. I knew it was going to make a difference but what I didn't expect was just how HUGE the difference would be. It drives like it should have always now. And it really exemplified the governor work. Here's a short video to show the difference between my earlier part throttle acceleration vid with the loose converter and now. Albeit The 1st video was made at the throttle position it took to actually get the car moving and the newest vid shows how little throttle acheives the same thing as well as the cripness of the once muddy shifts. [video=facebook;10151191146177479][/video]

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