Supposively, we change the weights in the governor to change the shift point RPM. The governor has two weight pieces, located 180* apart which swivel out. BTW: I noticed that my stock tranny (which is now a backup to the ProBuilt unit) governor has two different springs in it. I cant tell if the small weights are the same or not.

I bought a B&M governor kit to change the shift RPM of the 1-2 shift and the 2-3 shift. This kit came with 6 weights and 6 springs. The instructions say to replace the weight with a lighter weight if I want to increase the shift point, as I do ( from 5200RPM to 5800RPM). Do I change both weights on each side, or should I work with just one? Any experienced users here?

 

You can change just one weight or both; whichever gets you where you want to be. What really helped me was weighing the stock and B&M weights on a scale. That way I could keep track of changes in shift RPM with different weight configurations. I ended up grinding some material off one of the B&M weights to get within 100 RPM or so of what I was shooting for. Went through at least 5 different weight combos before declaring victory.

 

I weighed the B&M weights today at work, but I will not be able to weigh the stock weights until Tuesday.

BTW: I have an oppurtunity to race at Norwalk on Monday, so I accepted the chance. So I will have to get this shift thing done this weekend without weighing the stock weights.

About your comment about grinding a bit off of the last weight, I had the thought that I should just take a little bit off the stock weights until I get the shift point up to where I want it. But, by doing this, I will not be able to go back to where I was, but then I dont want to go back anyway.

 

Could always go to the Scrap yard and pull out the wieghts of a different tranny, and fool with those, or get them as a replacement if you want a cheap set for your modified ones.

Will the shift RPM be completely dependet on wieght and spring set up, or is it variable between cars, meaning a car with more or less power will shift at a different RPM using idenical weight and spring combos?

 

The governor assemblies are calibrated by GM for each specific application. If you go to a dealer and try to order a governor they will ask you all kinds of questions about the car. The tire size, gear ratio, transmission, engine, weight of the vehicle, etc. all influence the way the governor reacts.

Thats also why it's a trial and error process to get the shift RPM right. Try to make small changes so you can gauge the improvement. Start with weights and fine tailor it with springs. I made three changes to my Blazer before I got the 5,500 RPM shift point I wanted. Now I need to completely redo it because I've changed gear ratios, tires, converters, and several other things. It shifts at like 4,500 now, but usually I just shift it manually. Eventually when I stop changing stuff I'll recalibrate it...

 

Alright now, I popped off the governor cover (its not the bolt in type) and pulled out the governor. I changed the two inner weights to the B&M weights which were closest in weight but a bit less. I used a #3 and a #4... And I re-installed the stock springs. The 2-3 shift now occurs at 5900 to 6000 RPM, just as I wanted,,, but the 1-2 shift is maybe 6300 RPM.

Can I get the 1-2 shift down a little without effecting the 2-3 shift? What do I do?

The tranny also does not want to downshift from 3 to 2 (its always been like this). Is that the function of the detent cable?

 

You've got valvebody issues.

The 700R4 is designed to hold 1st gear longer in an attempt to make teh huge drap in ratios between 1st and 2nd seem less noticable. I'm not really sure how you can change that (or even if). Talk to Dana at Pro-Built. He's the guy who would know.

Perfect time to install a TransGo Reprogramming kit...