Auto Trans Kick Down Cable

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luvs2getmuddy

Well-known member
Oct 1, 2006
492
0
Aurora, Ontario, Canada
So My Kick down cable needs to be replaced(due to siezing/cracking/???). Anyway, I have it currently diconnected so that I can drive the truck around(I dont DDit) (switching gears manually), but would, ofcourse, like to have it repaired.
How does this Cable come disconnected from the Transmition? Looking at it from underneat, you can see it enter the tranny in the top left corner, but how does it unplug from therE?

Thank you.
 
ptschram

ptschram

Well-known member
Sep 27, 2004
21,955
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In the shop doing the Lord's work one broken Rover
www.ptschram.com
First off, DON'T RUN A ZF TRANSMISSION WITHOUT THE KICKDOWN CABLE!!! If you continue, go ahead and have Will send you a transmission.

The kickdown cable fits into a cam/bellcrank on the left side of the valve body. It is a real PIA to get to and get the old one out/the new one in as you must rotate the cam/bellcrank and simultaneously slide the cable from the cutout in the cam/bellcrank.

The sooner the better.

I believe I have one in stock Might even be genuine, but Will can probably beat me on price :)
 
L

luvs2getmuddy

Well-known member
Oct 1, 2006
492
0
Aurora, Ontario, Canada
Damn. How much will it be for the Kick down?

Why can't I run the truck without the Kick down?
My Friend had a GranD Cherokee and even towed with the kickdown disconnected? Just curious, not calling you a liar.
 
stevo

stevo

Well-known member
May 4, 2004
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I don't think the "kickdown" cable is really a kickdown cable. I always thought it was feedback to the tranny on where the throttle was and where the line pressure should be regulated to (or something like that). Not just a simple kickdown. I thought if you run with it out of spec your line pressure will be too high or low and some bad consequences may result.
 
stevo

stevo

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May 4, 2004
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I may have mispoke on that a bit - it might not affect line pressure directly....I ran across the original description off a volvo site for the ZF 4Hp22. Sounds like with it disconnected the valve body pressure will be low resulting in slow/sloppy shifts all the time - I would imagine that would result in more clutch pack wear.


Here is what I found:

The kickdown cable is used to regulate a pressure in the transmission valve body. This is called throttle pressure. The throttle pressure is effectively a pressure that tells shift valves in transmission how hard you are pushing the throttle and these shift valves now have a contest to see if governor pressure or throttle pressure is going to win. This pressure is also used to apply the clutches/brakes that engage a gear and the higher pressure goes along with higher engine power at higher throttle. Firmer shifts are a result of higher throttle pressure. If throttle pressure wins the contest the trans remains in lower gear, if governor pressure wins the trans upshifts. Governor pressure is directly related to driveshaft, and thus road speed. If you tighten cable you increase throttle pressure and the whole shift point/road speed map goes higher. If you loosen cable the shift point map moves lower. The trans throttle cable (kickdown cable) also depresses a valve if you (or the throttle spool) pull the cable all the way out past that hard spot which is a detent to make you aware of the actual kickdown feature. The kickdown valve increases the throttle pressure drastically above the linear rate that you get from the rest of the throttle pedal travel range and makes the gearbox goes to lowest possible gear allowed at the road speed you are at when you activate it.
 
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j_button

j_button

Well-known member
Apr 25, 2004
64
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Dallas, TX
Anyone know the correct procedure for the cable adjustment? Thanks to Stevo, I just put his engine in my GDE. It actually runs pretty good. Somewhere in the swap I must have spun the nuts on that cable. First trip around the block was some serious whiplash between 1 and 2 and never went past that. I loosened it way up and then sloppy advancement to the next gear early. I've since just been moving it after each little ride. It seems to be shifting normal but would like to have used some procedure if there is one... -JB
 
agbuckle98

agbuckle98

Well-known member
Mar 10, 2006
1,831
1
luvs2getmuddy said:
So My Kick down cable needs to be replaced(due to siezing/cracking/???). Anyway, I have it currently diconnected so that I can drive the truck around(I dont DDit) (switching gears manually), but would, ofcourse, like to have it repaired.
How does this Cable come disconnected from the Transmition? Looking at it from underneat, you can see it enter the tranny in the top left corner, but how does it unplug from therE?

Thank you.
Click to expand...
I just did one of these on a D1 for the first time ever. I was absolutely DREADING the job, but all said and done, not too bad. Very messy though. You will have to drop the pan, and valve body, then you will see the cable end and it will be fairly straightforward from there. I fiddled with the adjustment for a while untill the truck would downshift as I felt it should. Cable came from Atlantic British, about 50 bucks, perfect fit. PM me if you have questions about the job.
 
stevo

stevo

Well-known member
May 4, 2004
186
0
mbrummal said:
Open the throttle all the way and adjust it so the cable is pulled past the resistance near the end of its travel.
Click to expand...

Yeah, I think the resistance at the end is the actual "kickdown", which should come at WOT. I think the rave CD says there should be a 1.5-3 mm gap between the metal crimp on the cable and the cable sheath (throttle end) with the throttle closed. Can't remember the exact number, but seems like its around 2 mm or so. I can look it up at home.

I have heard that that its pretty sensitive to adjustment. When I got my truck the p.o. had tightened it up quite a bit to a 8-10 mm gap. I put it back at what RAVE recommened.

JB - my classic tends to have hard 1-2 shifts - especially at light throttle - when its at anything over 20-25% throttle it seems to shift fine. Definately improved when I put the cable back where it should be.
 
L

luvs2getmuddy

Well-known member
Oct 1, 2006
492
0
Aurora, Ontario, Canada
Lots of useful replies.
I am going to check with a few shops to see labour cost. I have the filter and gasket, will probably buy the cable new, to make sure I NEVER have this STUPID problem again. Not planning on tackling the job myself though.
 
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