Posted By: ademon
How to get trans to shift at a higher rpm? - 09/06/09 11:55 PM
got a sb with 1971 727, trans go shift kit, bolt in sprag. 9.5" converter ect.. ect.. when in drive it shifts from 1 to 2nd at about 15 and to 3rd at 20 with normal throttle. when floored it shifts at about 4,800. carb is a holley with the right bracket and downshift linkage, at full throttle the linkage has the trans line psi bracket all the way back. any ideas?
Posted By: Neil
Re: How to get trans to shift at a higher rpm? - 09/07/09 12:01 AM
The tailshaft governor weight and springs are what controls the wot shift points IIRC.
Not sure how you raise the parts throttle shift points. Probably somewhere in the valve body?????
Posted By: 1_WILD_RT
Re: How to get trans to shift at a higher rpm? - 09/07/09 12:37 AM
You'd have to check the factory service manual for a spec but most shift around 45-4800 @ WOT.. Increasing the length of the "kickdown" linkage (throttle valve pressure linkage) can have some minimal effect but the max TV pressure is equivalent to line pressure so governor valve weight is the true limiting factor.. TV Pressure can effect 1-2 & 2-3 part throttle shift points..
Posted By: racealittle
Re: How to get trans to shift at a higher rpm? - 09/07/09 12:47 AM
I'm not an expert on what rpm an original 340 727 trans shifted at in drive, but 4800-5000 rpm is what I would expect out of a good 727 car trans that has a Transgo TF2 kit in it.
I have bought the governor weights to correct the shift point. You have to talk with Rick at A&A about what he thinks is the right governor weight. Choosing the right weight depends on how your trans is built, your tire size, and your choice of gear. Turning up the line pressure in the trans can also raise the shift point.
If Rick specs out the governor weight and it doesn't suit your need, he will exchange it until you hit the shift point you require.
Posted By: gd9704
Re: How to get trans to shift at a higher rpm? - 09/07/09 01:37 AM
How involved is changing out the governor?
Posted By: BSB67
Re: How to get trans to shift at a higher rpm? - 09/07/09 02:19 AM
If you have your line pressure where you like it, you'll need to change the govenor to move the wot shift point. If you're trying to get to 6000 rpm or less, you can probably get there by reducing the weight of the inner weight. If you're looking for something higher, you'll likely need to change the spring as well.
What rpm does wot 2-3 shift happen? If 2-3 shifts at a lower rpm than 1-2, then adjust the governor to the desired 2-3 wot shift point, then change the 1-2 shift valve spring to get the 1-2 to the desired rpm.
Posted By: YO7_A66
Re: How to get trans to shift at a higher rpm? - 09/07/09 02:51 AM
Changing the gov will change the light throttle shift rpm too. Rick will need to ask you a few questions about your setup before he will suggest a gov kit. Also, ask Rick about the Split-Shift spring kit becuase you will most likely need it once you have the new gov in. This kit contains some springs that you will need to swap out in yoour VB. If you installed your TF-2 kit, then you can EASILY swap one of these springs out in the 1-2 shift piston to tune the WOT shift differences between the 1-2 WOT and the 2-3 WOT shifts. In other words, once you add the new gov and your goal is to get both the 1-2 and the 2-3 WOT shift points to the same rpm. If the new gov makes a large difference in shift points (lets say 5400/5800rpms), then the kit will have a spring (with instructions) that may allow the shift points to become closer (maybe 5600/5800rpms).
I have used two of the A-A gov's and each time I wanted to get both WOT shifts within a 100rpm difference, I had to use the A-A Split-Shift spring kit to get me close (if I remember right, both times I was within 200rpms). Then to get my shift points even closer (I was beening anal about it), I bought some springs from a spring manufacturer once I measured a couple of the 1-2 shift springs. Then after some testing I was able to get both my shifts points to the same rpm. You can also use the line pressure to gain/lose shift rpms too.
I am a huge fan of tuning the shift points in an auto car. The valve body can be fine tuned just like the carb and the ignition of a car.
Posted By: demonH1B
Re: How to get trans to shift at a higher rpm? - 09/08/09 02:34 PM
I too vote to shift manually at wot.
Posted By: 440newport
Re: How to get trans to shift at a higher rpm? - 09/08/09 10:03 PM
not to hijack but on a related note, my car shifts early on the 1-2 but the 2-3 shift is just about perfect IMO. I have 3.91 gears and unless I'm really into the pedal the 1-2 shift happens at about 5mph. The 2-3 shift happens at about say 30mph normal driving and about 75mph at WOT. Can the 1-2 shift be adjusted without effecting 2-3? The throttle pressure linkage seems to be adjusted correctly (bouchillion cable setup)
Posted By: Dougsmopars
Re: How to get trans to shift at a higher rpm? - 09/08/09 10:38 PM
Check your kick down linkage. There is a small hole in throttle bracket and pivot. Insert a drill bit through those holes. Un snap the lower rod. adjust the lower rod so in it's natural state it will snap back on. Then remove the drill bit. Hold throttle wide open. Adjust upper rod so that at WOT there is only a bit of free play on trans lever. You don't want the lever pressed back hard. It needs a little free play. Many people forget to adjust the lower rod correctly to get the proper ratio.
Posted By: racealittle
Re: How to get trans to shift at a higher rpm? - 09/09/09 01:07 AM
Shifting an automatic manually is fine most of the time. However, I have noticed that many of the newer cars are electronically controlled and some have the autostick feature.
The auto stick feature is a nice feature, but not really required because the engineers have things figured out electronically. Most of the newer cars have shift points at WOT that most of our older muscle cars never even came close to. So a few of us decide to tune a transmission to match the optimum shift point for the combination we have built, (just like the engineers are doing in modern cars). I can't understand why there would be nay sayers that think the only way to do something is "their way". To each his own. After I have tuned the carb, my timing, my motor, etc., the nay sayers suggest it must be only shifted manually.
What was I thinking? Or do the nay sayers have their heads in the sand like an ostrich. I'm not looking to pick a fight, but I just don't understand why the right to have choice is so readily put down by a few who prefer to manually shift. I manually shift when I feel like it, and let the car do the job it is tuned to do the rest of the time.