The initial starting point for the kickdown linkage spacing is . 018" or eighteen thousandths.
That should give you a decent starting point. It did on mine... in fact you can use a 1/8" drill bit shank for this.
Philip is dead on too... you must have that spring on the throttle vavle cable, it is important. He is also right that without it, you'll be calling a transmission Guru in a short time... .
If the dealer did a service then go back, ask them to set your idle line pressure to about 58-59 psi (nearing the upper end of the acceptable range), and your WOT line pressure to about 100-110 psi (double check that one to be sure. ) either way, you WANT it to be at the 3/4-7/8 of "acceptable range".
This will give you a firmer engagement at idle, and a little more line pressure when pushing it a bit so you don't have more slippage on the bands.
You can also check your TPS settings while you're under the hood.
Here is the file I've compiled to get your TPS set up with an initial starting point. (TPS controls ONLY the 3-4, 4-3 shift.
Check and note your current readings before you change anything though, you want to know were you started from.
>> TPS ADJUSTMENT... .
The TPS has a 3 wire connector on the top, engine side.
The center wire is orange (with some sort of stripe) I believe.
Under the TPS body, is a shaft that protrudes downward. The shaft has a hex head end that fits into a 'female' hex socket.
This shaft is lightly spring loaded. When the hex headed bolt end is pulled upwards on removal the head/shaft may 'snap rotate' an 1/8 turn or so, so watch it as it comes out since it needs to go back in the same position. ( Removal of the TPS happens when you want to access the inside of the AFC housing to adjust the diaphram or starwheel. ) Just be sure to take a preliminary reading off the TPS before you remove it if that is part of the job your doing. (Like when taking the top off the injection pump)
Right near the top of the shaft were it first comes out of the TPS body, are two "flats" were you put your open end wrench to adjust.
You'll need a DC Voltmeter, as safety pin, or paperclip with the end slightly sharpened, and a combo wrench. I think its a 10mm.
Slip the safety pin or paperclip into the 'socket' part were the center wire comes out of until it makes connection with the metal jacket inside.
Connect the "+" probe of your DCVM to this.
Connect the "-" probe of your voltmeter to the "-" terminal on the battery (it's just convenient)
Turn on the Ign. key (do not start truck) and check the "at rest voltage".
It should range between . 6 VDC and 1. 20 VDC. (make a note of the reading for reference. )
Next, slowly cycle the throttle smoothly to WOT then back to "at rest" and watch the meter.
It (the needle) should increase smoothly up and down with no jumps or spasms/twitching.
If it does, the TPS is still working ok, if not you've got a dirty one or its failing.
I believe the total increase (above "at rest voltage") should be about 2. 75 VDC.
Now, you need to go back to that shaft coming out from under the TPS.
Use the wrench to adjust the voltage SLIGHTLY!
Start with + . 2 VDC to begin with (to delay 3-4 shift a bit) OR -. 20vdc (to have 3-4 happen earlier. )
Increasing voltage will cause the 3-4 shift to happen LATER.
Decreasing voltage causes the shift to happen sooner.
I found that there was a point were the shift happened later, but also tended to cause the downshift (4-3) to be a bit touchy too, so you need to adjust a BIT and drive each time.
When you do your test drive try to use the same throttle pressure/RPM for each, that way you'll know what effect you had with the adjustment. I did a "medium" throttle (1600 RPM) and a WOT test each time.
Before I had the transmission work done mine ran just fine at about . 7 VDC ~ . 8 VDC "at rest".
Last thing to ckeck... make sure that your TV cable returns properly. The lever on the trans. case should move all the way forward with the truck off/idle. I had to add a "universal" throttle spring to be sure that happened, otherwise the line pressure(s) at idle are already increased above what they are supposed to be at idle and you may have harsh engagement when shifting from "P" or "N" into "D" or "R".
In the event you need to remove the top TPS body itself remove the two screws holding it down. Carefully lift it up and note that underneath there is a plastic slot and key type indexing. Once the TPS body is off you can turn it over and spray electrical contact cleaner into it, working it back and forth. The use some gentle compressed air to dry out the spray cleaner (it evaporates pretty quickly). Once done, re-install it and try the re-set procedure again and watch your dcv meter for smooth movement.
You can find some good pics of this thing in my 'Readers Rigs" gallery under VE Gallery label.
Hope this helps you if you need to work on the dreaded TPS.
Bob. aka: BushWakr
Attention: TDR Forum Junkies 
after checking my settings and adjusting TPS. Best I could tell; was 1. 2dcv at rest,2. 1dcv at WOT. Now . 8dcv at rest and 1. 7 at WOT. Shifting to OD about 70mph
the way... ... ..... 
