Transmission kickdown cable question

[T4Rscott]

Hi all,

Could someone take a few minutes and explain how the trans kick-down cable works and how it should be adjusted? Does tightening the cable make it down shift quicker?

Just want to make sure I've got it right.

Thanks

 

[LittleCaesar]

Scott,

I will leave someone else to give you the pointers of how the transmission kick down cable works. I know, but not well enough to make it lucid for ya to understand.

Tightening the cable results in firmer shifts. I have always had the little stop piece on the cable lined up with the boot at the end of the cable. Two 14mm flare nut wrenches should help ya tighten or loosen it.

 

[BlackCat914]

Hi all,

Could someone take a few minutes and explain how the trans kick-down cable works and how it should be adjusted? Does tightening the cable make it down shift quicker?

Just want to make sure I've got it right.

Thanks

Tightening the cable increases line pressure, which gives you nice, firm shifts. Tightening the cable is also easier on your trans, because the firmer the shift, the less slipping is involed in a gear change, thus generating less heat. (assuming you have an adequate trans cooler than can offset the heat generated by increased line pressures) Basically, the cable is there to sync the movement of the throttle plate to the valve body.

 

[02_SE_Runner]

The Governor will decide what gear to shift up to, the kick down cable decides on when to downshift and what gear to put it in. Another thing it does is when you stomp on your gas pedal, it will downshift for you for a better acceleration. I am not quite sure if tightening it will benefit you much, but if there is slack, you SHOULD take out the slack.

 

[T4Rscott]

Thanks for all the replies. I think I have it adjusted correctly. I never knew how far to go when tightening the cable. I have the small plastic piece just showing from under the boot.

 

[iowajosh]

I did this. The little grommet on the cable is supposed to protrude from the rubber end cap thing zero to 1mm or so. If it is too tight, you downshift constantly.

 

[TheeMikeB]

Yeah I thought the kick down was exactly that, a "kick down" cable, so when u mash the pedal it automatically shifts down the tranny. That way you don't have the lag of the pressure needing to build up in the transmission to shift.

 

[BlackCat914]

Yeah I thought the kick down was exactly that, a "kick down" cable, so when u mash the pedal it automatically shifts down the tranny. That way you don't have the lag of the pressure needing to build up in the transmission to shift.

Technically ya, but it also increases shift firmness in general.

 

[joey326]

I have a 96, 2.7,2wd,automatic trans,293k miles. I just replaced rear main crank seal along with front and rear seals on tranny (A340E). Put it all back together and now when you shift into Drive or Reverse from Park, a substantial hard engagement is happening. I may have damaged the Throttle Valve Cable. I reused the 9k old synthetic ATF. Any insight as to why this may be happening? I would appreciate any help. Thanks. Joey326
New ujoints on driveshaft also installed by driveshaft shop.

 

[19963.4lsr5]

The A340 is a electric shifted trans from the TCM module. The TCM has no clue what position the TV (kick down) cable is in. IMO it's just for line pressure control.

 

[gamefreakgc]

I have a 96, 2.7,2wd,automatic trans,293k miles. I just replaced rear main crank seal along with front and rear seals on tranny (A340E). Put it all back together and now when you shift into Drive or Reverse from Park, a substantial hard engagement is happening. I may have damaged the Throttle Valve Cable. I reused the 9k old synthetic ATF. Any insight as to why this may be happening? I would appreciate any help. Thanks. Joey326
New ujoints on driveshaft also installed by driveshaft shop.

Mine's done that as long as I cant remember, and that's with a new transmission 4 years ago (I didn't put it in though). When cold, the transmissions give it a little bit of a jerk, it's pretty common.

When warm though, it shouldn't jerk much if at all.

 

[nc-grayson]

Sweet. glad this was bumped recently.

Can this quotebe clarified/verified for the lay man?

Tightening the cable increases line pressure, which gives you nice, firm shifts. Tightening the cable is also easier on your trans, because the firmer the shift, the less slipping is involed in a gear change, thus generating less heat. (assuming you have an adequate trans cooler than can offset the heat generated by increased line pressures) Basically, the cable is there to sync the movement of the throttle plate to the valve body.

Am I supposed to assume that the "tighter" the cable, the firmer/harder the shift, is easier on the transmission?

I know nothing about transmissions, I'll admit I'm a newb. But amateur me would think that the slower shifting would be easier on the trans. Anyone care to enlighten me?

 

[cashmoney]

The longer it takes to shift the more it slips. Autos need to have quick shifts. There is a distinct difference though between quick and firm and fast and harsh. Fast and harsh can break stuff. Quick and firm will make it last. You should feel the shift and the RPM's should drop instantly but it shouldn't be so hard that it feels like your spine is going to snap. But with a stock valve body you won't have any issues.

 

[sjwelna]

FWIW, it is possible to overtighten that cable. The best way to make sure it is set as tight as it can be but not too much, is to hold the throttle plate open all the way, then tighten that cable down and leave just a little bit of slack/give with the throttle plate all the way open, and tighten the nuts to hold it in place. This way when you step on the gas you don't stretch/break that cable if you go wide-open-throttle. That's how I set mine and it works perfectly. I might eventually remove the cable completely and just lock it in place at full pressure down at the transmission, but that's a project for another day.

-Steve

 

[cashmoney]

Only thing I'd be concerned with doing that is it might hold the shifts to long. Ran into that when I tried it with my dodge.

 

[jhfleet]

Other than setting it per the FSM, I wouldn't be screwing around with the transmission cable adjustment. Too much or too little hydraulic line pressure are both bad for transmission life.

 

[gamefreakgc]

FWIW, it is possible to overtighten that cable. The best way to make sure it is set as tight as it can be but not too much, is to hold the throttle plate open all the way, then tighten that cable down and leave just a little bit of slack/give with the throttle plate all the way open, and tighten the nuts to hold it in place. This way when you step on the gas you don't stretch/break that cable if you go wide-open-throttle. That's how I set mine and it works perfectly.

-Steve

This is a good explanation. Note that the transmission cable is ONLY for down-shifting when you give it more throttle. It does NOT affect normal up-shifting. If you are having issues up-shifting, there's something wrong with your transmission.

 

[jhfleet]

This is a good explanation. Note that the transmission cable is ONLY for down-shifting when you give it more throttle. It does NOT affect normal up-shifting. If you are having issues up-shifting, there's something wrong with your transmission.

I dunno about that. According to what I've been reading, the so called "kickdown" cable on the electronically controlled A340 is not used to adjust shift points since this is controlled electronically. It's only function is to set line pressure consistent with throttle position. I understand that early versions of the transmission did control shift points hydraulically and could be adjusted with the cable.

 

[gamefreakgc]

I dunno about that. According to what I've been reading, the so called "kickdown" cable on the electronically controlled A340 is not used to adjust shift points since this is controlled electronically. It's only function is to set line pressure consistent with throttle position. I understand that early versions of the transmission did control shift points hydraulically and could be adjusted with the cable.

Yeah, I've been told that newer 4Runners (01-02 I think) have a slightly different setup. For those at least 98 and older, our downshifts are 100% controlled by the cable. If the cable is slack, it will have a really tough time shifting down under acceleration, if at all.

 

[jhfleet]

Yeah, I've been told that newer 4Runners (01-02 I think) have a slightly different setup. For those at least 98 and older, our downshifts are 100% controlled by the cable. If the cable is slack, it will have a really tough time shifting down under acceleration, if at all.

Not according to the FSM for the 1996 T4R. The A340E/F section of the manual states that the cable is used for setting hydraulic line pressure and gives a procedure on how to set pressure to specs by adjusting the cable while using a pressure gauge. Another paragraph in that section states that transmission shift points are controlled by the #2 transmission speed sensor in conjunction with the signal from the throttle position sensor. Increasing line pressure over specs might have an effect on downshifts, but that's not the purpose of the cable according to the FSM. I'm no transmission expert, but it seems pretty definitive to me.