looking for input: mechanical p pump dt466/mt643 combo. rmps, modulator, shifting pattern.

[kyletheyeti]

Hello to all.

I recently had a shop do a tranny swap from my stock at545 to the mt643. The trans was used but supposedly rebuilt and in very good condition. Years ago I had my 545 blow on me while on a cross-country drive and I had it replaced with another 545 like an idiot! The mechanics that did that work didn't adjust the modulator cable correctly and unbeknownst to me it never shifted quite right, slowly wearing out the 2nd gear clutch. It's pretty frustrating how international shops will abandon you if it's not a stock setup.
Now I'm trying to make sure that the new trans is shifting correctly and avoid another costly mistake. I'm hoping to hear from those who have this engine/trans combo. I have swapped out both my engine and trans so nothing is stock but i know this is a common combo.

Questions:

1.) I've read previous posts here on the adjustment of the trans modulator cable to have about 1/8" of slack when the throttle lever is all the way open. Mine is just about there but I'm wondering how hard one needs to pull on the cable to see that "slack". Mine moves that much but it's only doable with a pliers. Should it be easy to do by hand? My throttle lever has been welded/modified so it's pretty much a 'bend it til it fits' situation. I also read in that post that the hole in the throttle lever should be slightly slotted to allow for the movement of the cable set screw but wouldn't that negate the function of the jam nut on the screw? anyone have pictures of their lever?

2.) When i start out from a complete stop, it's like the trans tries starting in 2nd gear and immediately lurches back to 1st. I know that the unit has fresh oil and a brand new governor. Is this symptomatic of the modulator cable being out of adjustment or something more?

3.) When I'm accelerating under normal throttle, i see upshifting around the 2200-2300 rpm range. and under full throttle more like 2500 rpm. When it shifts into 3rd, which is where i understand the locking torque converter to kick in, it drops to a much lower rpm than is does in 2nd. It's one thing when under full throttle but at half throttle/ slower speeds like around town the rpm drops very low like around 1000. Is this normal or does it also suggest something is out of adjustment? Can anyone with this engine/trans combo tell me how their setup acts under these conditions?

Thanks in advance!

 

[sportyrick]

something doesn't sound rite, the slack should be when the throttle is closed and all slack should be removed as it advances, sure you don't have that backwards?

 

[kyletheyeti]

something doesn't sound rite, the slack should be when the throttle is closed and all slack should be removed as it advances, sure you don't have that backwards?

everything i'm seeing says that the cable should have that 1/8" of slack with the throttle lever open or full fuel

 

[sportyrick]

My DT466 and 3060 is tech2 and has a mechanical potentiometer kick down and mine is slack when throttle closed. You sure it's on the right side....as in position on throttle? unhook it and try to drive it, should work correctly just won't hold transmission in gear longer....that's what the kick down does, throttle pressure for high power shifts and holding it in gear longer. Someone else pipe in here.

 

[kyletheyeti]

My DT466 and 3060 is tech2 and has a mechanical potentiometer kick down and mine is slack when throttle closed. You sure it's on the right side....as in position on throttle? unhook it and try to drive it, should work correctly just won't hold transmission in gear longer....that's what the kick down does, throttle pressure for high power shifts and holding it in gear longer. Someone else pipe in here.

mine is slack when throttle is closed too. not sure what you mean about the position on throttle and unhooking it. I'll take some pics