Hi, a friend of mine has a 2001 cummins with an auto, I am trying to adjust his throttle valve cable under the hood, there is almost no change in shift timing until I get to a certain spot, then it changes it drastically, WOT in one spot shifts to 2nd and 3rd about 2900 rpm, loosen it just a tiny bit and it drops to about 2000-2100, (cant remember exactly) it seems as though there are only 2 spots where it is different, and is not variable at all. Does the TV cable need to be replaced or something? Please help, stumped

 

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Have you checked whether the cable is frayed or damaged?
Has anybody been into this tranny and turned the pressure adjusters or installed some VB, shift kit etc?
The spot you mention could be the spot when the kickdown is getting activated- 2900 sounds quite right to me for WOT. I usually adjust it so that it has almost 0 play at WOT seen on the tranny (helper flooring it with engine off, look at the TV arm on the tranny, you shouldn't be able to move it more than a hair )

HTH

AlpineRAM

 

It has a valve body in it, the guy that owned the truck before him had it installed, not sure what kind, one of the bigger names, I just cant remember who. nothing else has been done to the tranny, it has good pressure, and shifts good, so it is a good valve body

like I said, if its at 2900, I can loosen it just a tad at a time and no change until suddenly it drops to about 2100, seems as though there is no adjustibilty.

 

There is almost no adjustability when in kickdown. The kickdown valve depressed tells the tranny to wind out each gear. When you losen the TV cable to a point that it doesn't activate kickdown it will just do the standard upshift under heavy throttle, where 2100 -2300 rpm sound right to me. I would not want to have a lose TV cable adjustment since this lowers the line pressure significantly and can induce slippage. The shift strategy to let the engine rev quite high under WOT has it's benefits because after the shift the engine is in the optimum power range and already has lots of boost to continue pulling.
At WOT mine pulls up to 3100 before the 2-3 shift.

HTH

AlpineRAM

 

It is tough to find that exact sweet spot, but keep adjusting it so it ALMOST HAS absolutely no play in it. Are you sure you have plastic clip in place properly, or has it maybe become too stretched or tips worn out, and now won't clamp holder properly into locked position?

If locked in place right it should not change the rpm's after setting. Plastic clip can easily be broken/damaged if forced. I have mine set to 3200rpm shift point under hard acceleration, shifts firm and hard through all gears.