70 Challenger 440 727 Shift Points

[schlett7nu1]

I have a 70 Challenger 440 with it's original 727 3410670 auto. The shift points from first to second to third are extremely quick. I adjusted the linkage at the carb and now first to second is perfect. However, second to third remains too quick. Is there a separate adjustment that allows one to lengthen the shift point between second and third?  I'm referring to "quick" as the time between shifts under a normal acceleration rate. The tranny is bone stock in a 28k survivor car. Last winter I dropped the pan an oil was clean with no debris in the pan. Currently, 1-2 is around 15mph and 2-3 is under 20mph. I believe 2-3 should be between 25-30mph.
Dereck

[Chryco Psycho]

Wrong guy to answer this really but this is what I hate about Autos , I want the trans to do what I want not what it wants to do !!
I believe the answer is in a shift kit [Trans Go 2 is awesome ] different line pressures adjusted in the valve body & the governor weights inside the tailhousing to make it work right .
I have only driven 1 727 set up correctly in all of my years , I wish I could track down that builder & learn from him but he is likely dead now . he built the trans back in 83 for my friends Little Red Express , no other auto trans has worked liked that one including the few I built although I did get close .

[chargerdon]

The "speed" at which our torqueflites shift to the next gear is dependent on several things:

1) Adjustment of the shift rod linkage.    It should be adjusted so that it doesn't reach maximum until full throttle...and when cruising below 50 a full throttle should engage the downshift mechanism.   It if is adjusted too light then the upshifts will occur way too early.    This is the most probable thing to check.
2) The adjustment of the pressure regulator...to change it you have to drop the pan, and screw it in tighter or less.   No, it is not a direct speed adjustment, but, rather the line pressure which does modify the points SOME.2)
3) How much throttle your giving it, as the more throttle the more the shift rod is engaged. 
4) The governor in the tail section...  it is weighted to control the shifts...   To modify the speed points a lot this has to be changed ..there are weight kits available.

5) Rear axle gearing...  4.11 axles will have a much lower speed for its shifts than the 2.71 axle...  I.e same governor speed but different car speed and obviously the tire size the same thing.

Lastly, there are shift improver kits that can be installed on the throttle body though most of them change the "quality..i.e crispness" of the shift itself not the speed at which they occur.

Generally, they will shift from 1-2 at a low of 8-16 mph with light throttle, and as high as about 32-45 mph under WOT.   2-3 will be under light throttle at about 15-25 and 60-80 under WOT.   This is plenty high enough for normal driving.   See page 21-71 of 1974 service manual for a chart.

On both my 904 that was in my car and my now 518 the 1-2 shift under floored throttle will occur around 30-35 mph and with my gearing that works out to only about 4,000 rpm.   To get the car to "hold" until the 5500 rpm redline, i simply pull the shift lever into the "1" and then manually push into "2" at the desired rpm.   Note:  The slap stick shifter makes this a lot easier  !!