400 kickdown

[53burb]

If I understand you correctly, if I use the kit, 2nd gear will kick in at a later RPM. The kickdown will also be enabled at a later RPM. So, right now, my kickdown is inop at over 2000RPM in normal cruising. The kit should let me increase this RPM range. This will have to wait until I change my rearend. I will talk to Summitt or B&M when I am ready. Thanks for the help. Just reread your post, it only changes at WOT?? Not at cruising in 3rd gear, then going to WOT, because you are already in 3rd, right?? But if you are in 2nd, it will hold 2nd longer before it shifts into 3rd. Any suggestions on getting it to downshift at 2000RPM + w/o doing it manually??

[crazy longhorn]

The gov recurve kit will raise & spread the WOT shift points. From what I have seen, it also raises the part throttle shift points somewhat. I dont run the elect kickdown on my longhorn, as I didnt want the 3 to 1 kickdown (lots of revs & squirrely!) the trans will downshift from 3 to 2 without the switch, & the shift out point is not affected (as much) from 2 to 3, as from 1 to 2. The shift kit in my trans lets me shift up/down @ any speed, or hold a gear to any speed manually.You might find that with the 3.08 gears, the recurve is not needed....your kick down & shift out points will be @ the same RPM relative to the driveshaft speed, but the truck will be moving faster with the taller gears. with the switch hooked up, & you shift out @ 4300 & 3700/3800, thats about right for a stock or mild combo. L

[ac102nv]

Originally Posted by 53burb

If I understand you correctly, if I use the kit, 2nd gear will kick in at a later RPM. The kickdown will also be enabled at a later RPM. So, right now, my kickdown is inop at over 2000RPM in normal cruising. The kit should let me increase this RPM range. This will have to wait until I change my rearend. I will talk to Summitt or B&M when I am ready. Thanks for the help. Just reread your post, it only changes at WOT?? Not at cruising in 3rd gear, then going to WOT, because you are already in 3rd, right?? But if you are in 2nd, it will hold 2nd longer before it shifts into 3rd. Any suggestions on getting it to downshift at 2000RPM + w/o doing it manually??

The purpose of the kickdown is only WOT. No changes to cruising shifts. By using the kit to modify the govenor you are changing the WOT shifts and to a certain extent the cruise shift points.
It's starting to sound like you want to modify part throttle shifts, I would recommed getting a good transmission book. When you start changing this stuff you need to know how the different "systems" work together, or it can be a real mess. I have one intitled "How To Work With & Modify the Turbo Hydramatic 400 Transmission"...Summit has as number MBK-0879382678, about $22. There's other sources I'm sure....

[53burb]

The part throttle shifts are fine. What I am interested in doing is, going to WOT from above 2000RPM. Assume I am cruising at 65mph, the RPMs should be at about 2600RPM with 26" tires (265/50/15). I would like to stomp on the pedal and it kickdown into 2nd until I let off the pedal. I have heard different things as to if the 400 w/o the electric k/d would do this or not. Am I making sense?? If the electric switch is not needed for 3-2 kickdown, and only for 3-1, at what RPM should it kickdown w/o using the switch?? I am only interested in 3-2 and not 3-1...Sorry if this getting confusing....

[crazy longhorn]

Years ago, I was told by a trans tech that the elect kick down ONLY affected the 3 to 1 kickdown, & while I accepted that for "gospel" , your test shows clearly that the elect hook up does in fact change the shift out point from 2-3 when the switch is activated. For my useage, I didnt worry so much about the automatic end of things. Add a transgo 400-2 shift kit, & you will have more control of the trans......it still does the auto thing as it should, but if you feel the need to punch the throttle @ say 65 mph, just pull it to 2nd manually.....& it will stay there to YOU shift it out(can you smell rubber smoke yet? ). The 461 Olds I ran in my longhorn (early 90's), would flat smoke the tires on a forced downshift @ full throttle(65 mph).....the best part was that when I shifted it around 6800 , that booger smoked the hides again & was running 100mph+ on those 3.40gears! Elect kick down flat did not work on this one......well it worked ok , if you dont mind driving in 2 lanes to hang on to an old truck I think you are looking for more manual control on the trans..... L

[Green Machine]

Gotta jump back in here, it is totally pointless to try to guess what rpm/speed the tranny will kick down at without a properly hooked up and working kickdown switch. Thats what is for. Once you have a switch hooked up to the carb or gas pedal that activates at WOT, then you can play with the governor weights and springs and the vacumn modulator to fine tune things. Shift kit may be an option also. The 400 does not have a cable like a th350, so it has does not have a direct way of knowing the throttle position, it relies on the vacumn modulator and the WOT switch for proper automatic operation. If you want to run without the WOT switch, you need to manually downshift unless you set the upshift points very high.

[crazy longhorn]

Originally Posted by Green Machine

Gotta jump back in here, it is totally pointless to try to guess what rpm/speed the tranny will kick down at without a properly hooked up and working kickdown switch. Thats what is for. Once you have a switch hooked up to the carb or gas pedal that activates at WOT, then you can play with the governor weights and springs and the vacumn modulator to fine tune things. Shift kit may be an option also. The 400 does not have a cable like a th350, so it has does not have a direct way of knowing the throttle position, it relies on the vacumn modulator and the WOT switch for proper automatic operation. If you want to run without the WOT switch, you need to manually downshift unless you set the upshift points very high.

Yes, you will probably make yourself "nuts" trying to modify the gov to change the pass gear shift points, without the switch hooked up. You WILL have a 3-2 kickdown without the switch......but probably not above say 45mph. If I am running 65 mph & need pass gear, I have to shift manually. If it were mine, I would hook up the switch, swap the gears,.....& see what happens L

[53burb]

Thanks for all the help guys. I guess it is working correctly. I guess if I want to use the passing gear at 65mph, then I will have to do it manually like you do. Happy Thanksgiving!!!!!