The shuddering problem in my brother's 83 904T transmission seems to be cured, but he still has no kickdown above 50 MPH.

The tranny shop guy told me that this highway speed kickdown is controlled by the governor in the tailshaft. Is this true? Any recommendations about how I would go about adjusting this highway-speed kickdown point? Remember, this is a 83 904T with part-throttle kickdown, a lockup tranny, and the wide-ratio gearset.

Thanks for all the help.

What is your rear end gear ratio Reed?

My 3.55:1 axel ratio in the Dart won’t let the transmission down shift from 48 to 49 mph on up, I suspect from too high engine rpm is read by transmission governor. Manually shifted, it will still down shift at any speed. I have not measured the line pressure (don’t have the gages), and suspect it is on the low side based on a bit of rpm run-up between shifts after the transmission has warmed up.

The car’s, I don’t know about stock truck rear end ratios, most often had 3.24 and taller gears which would allow for a higher road speed down shift for given engine rpm.

Check cable or throttle pressure rods for adjustment, perhaps your guy has left a little slop in them… I couldn’t get my kick down point adjusted correctly, so took the car to a shop to have a pro sort it out… Turned out that cable bracket was pivoting a few degrees, because it was held by one stud, under WOT, and this professional did not pick up on it. I didn’t either until I paid my money to him for a semester of tranny U, and decided to take the bull by the horns and make it work.

Axiom: One man’s shift point is another’s maladjustment.

My Lebaron has the part throttle kick down feature, but on a non-lockup three speed, and it is real sensitive to throttle pressure adjustment. Adjusted little too far in one direction, slow or large throttle impute gives an eventual part throttle kick down, adjusted a wee bit in the other direction the slightest throttle impute results in an instant down shift.

From what I have read about part throttle kick down valve bodies; throttle position, rpm, and preset line pressure all play a roll in shift points. In other words, if your tranny guy has dialed back the internal line pressure, or has it set at the low side of normal, this alone maybe delaying or preventing a higher rpm down shift point regardless of how far that throttle lever is moved.

Humm... I went from a simple eight word question into this long winded cranial dump of thinking out loud, sorry.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Thanks for the input, I appreciate it.

The van has a 3.2 rear gear ratio. I installed the Transgo SK-TF shift kit, so I don't know what the line pressure is now.

Interesting you mention the kickdown misadjustment. One of the techs who looked at the van said the kickdown was "two inches out of adjustment" and this was keeping the kickdown from happening over 50. He said a bracket was installed wrong on the motor and this was why the kickdown wasn't working. Well, I searched long and hard to find the factory correct van-specific two barrel kickdown linkage that I installed on my brother's van, so I know it is correct.

Guess I will be getting a gauge for the line pressure and adjusting the kickdown.

Before you blow a few bucks on a gage, make sure that the linkage is correct, and that there is full rotation solidly against the stop, of the throttle lever at WOT, ah, but you know this all ready; had to say it for the other folks following along here.

I just remembered that for the longest time I assumed that my carburetor had its throttle plates fully open when the accelerator was flat on the floor. Turned out to be a bad assumption, they were opening only 3/4th. of the way which caused kick down problems, such as no kick down at all. A second set of eyes sure helped with this adjustment. I had to shim the peddle mounting plate out a quarter of an inch to get more cable travel due to previous owner’s crappie floor board patch.

I don’t have my transmission book unpacked yet, trusting the dome here, so don’t take this as gospel, in other words double check this, but I recall that there were one maybe two bolts on the side of the valve body that needed be turned in or out a specified distance given in 1/16th or 1/32sec of an inch, and these adjusted line pressure on 1-2 & 2-3 shift.

Do you recall messing with these piston stop adjustments when you installed your shift kit, or was it just: loose an actuator spring: plug a passageway: and remove an O ring kind of project?

If you find that the linkage is not correct, just install a kick down cable, and be done with it.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

The shift kit consisted mainly of drilling a couple holes, swapping a piston, and changing some springs. I believe I left the accumulator spring in place.

I am sorely tempted to switch to a kickdown cable. Before the shop worked on the van, I made sure that the throttle was opening fully and that he kickdown lever was all the way back at WOT. It still didn't kickdown above 50. I haven't looked at it post-shop work.

Me quoting me: Reed, could be that is the shift point for your rigging. Still, with taller tires & higher rear end ratio your 50 mph engine rpm would be quite a bit slower than my car’s. With the extra weight & wind resistance of the van, that partial kick down should be right there with not much right foot impute up to at least 60 mph.

What rpm is that van turning at 50 mph? I know my transmission up shifts under WOT every time at 4000 rpm. I don’t remember at what rpm the transmission will not kick down, if it is 1200 rpm under shift point, or what.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

The van does 65-70 at around 25-2700 RPM. I would hazard a guess that at 50 MPH the van is loafing around 2000-2300 RPM.

The problem is my brother drive's like a maniac and is rarely at light or part throttle. I think this is one reason why he has gone through five transmissions (including two 727s) in three years. Anyway, the van usually requires about 1/3 to 1/2 pedal travel to keep up with traffic on the highway, so I am fairly certain the pedal is beyond the part-throttle kickdown point.

Reed you have got me thinking cars again. I have been preoccupied with this new house project since last July, and been pounding nails, plumbing, wiring, tiling, painting bla, bla, bla,, and recently prepping and seeding about 70,000 square feet of new lawn with a rake & wheel barrel… Frankly, I find I’m getting a little too old for this gig, but will muster on until done. It is kind of nice to sit and be cerebral for a change… Thanks.

I have dug out my HP Books copy of “Torqueflight A-727 Transmission Handbookâ€￾, by Carl H. Munroe: 2003 from a large pile of freshly moved boxes in the basement. In it, under; Troubleshooting & Testing, is the same list found in factory service manual of: condition; possible cause; and correction, but worded differently. Three of the eleven catch my eye that we have not discussed.

1. Line pressure too high or low.
Munroe directs one to page 207 for testing stock units (non race build) requiring two 0 to 300 psi gages, and “Governor pressure testâ€￾ too long & complex to list here. Ask you transmission guy if he performed any pressure tests on your unit.

2. Sticking or leaking governor.
Remedy is to remove governor, clean & smooth any rough spots. This can be accomplished with transmission in vehicle. Factory service manual describes reasons for sticking governor and how to remedy as well.

3. Sticking Accumulator, broken accumulator rings or springs. Low on my list.

4. Not listed, but where you had the valve body out for modification, did all the check balls get back in their proper location before reassembly? Have you called the kit’s manufacturer for possible remedies for non kick down based on their modifacations?

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Thanks! I'll check these out.