Improving Transmission Shifting (3 Viewers)

[lndcruz]

Mine already shifts plenty firm. Its actually a little harsh sometimes.

 

[Eicca]

Mine shifts ok, but I would like it to be a little snappier.

 

[Pinetop Cruiser]

Thanks for the writeup, Kevin. Sounds like a good one to send to FAQ's.

 

[Hilux]

I need to try this. My transmission is already in 3rd by the time I reach 20 mph, and MAN does it "slide" into gear. I'm going to try your suggestions in hopes that it firms up the shifts. It drives me crazy the way it shifts right now. In fact, I usually **** it manually................does anyone make a shift kit for the 343?

here ya go...

Well, shift points? Computers? We don't need no stinking shift points and computers!


Shift Controllers (Flappy paddle it)


Thank Pirate A340 FAQ

 

[Tools R Us]

I need to try this. My transmission is already in 3rd by the time I reach 20 mph, and MAN does it "slide" into gear. I'm going to try your suggestions in hopes that it firms up the shifts. It drives me crazy the way it shifts right now. In fact, I usually s*** it manually................does anyone make a shift kit for the 343?

The shift points are controlled by the ECU, this won't change them. They are largely determined by load, so if you nail the throttle, it will hold in each gear longer or push the "power", the motor will rev higher before shifting. For me the shift points are fine, if needed, it will red line the motor before shifting, for normal driving there isn't a need to rev the motor, unless your looking to reduce gas mileage?

There isn't a shift kit available or I haven't found one? A couple of shops tune the valve body, basically a more aggressive version of this. After playing with this a bit, my concern would be smoothness in low range. When tuned to shift firm in high range, low range becomes very firm, spinning tires even on low throttle shifts.

If your not worried about off-road, then there are more options. The first would be to shim/stiffer spring/remove the spring and replace with a rod, the accumulator springs. This will shorten shift time and depending on how far you go, make for neck snapping shifts.

The ECU does a few things to reduce the shift harshness/drive train shock, for example it retards the engine timing when shifting. Short of reprogramming it, nothing can be done.

 

[landtank]

I need to try this. My transmission is already in 3rd by the time I reach 20 mph, and MAN does it "slide" into gear. I'm going to try your suggestions in hopes that it firms up the shifts. It drives me crazy the way it shifts right now. In fact, I usually s*** it manually................does anyone make a shift kit for the 343?

You don't have anything in your sig line but if you are running different tahn stock tires or gears then correcting the speedo will influence the shift points if you haven't done this already.

 

[Hilux]

Is there a A343 FAQ? If not, there needs to be one... (And can anyone tell me what the 3 in A343 means?)

Do the TPS and Throttle body affect the points?

"The throttle position cable controls the line pressure only, it does not affect shift points. Shift points are determined by throttle position information from the TPS sensor on the throttle body.
Thus it is easy to perform a free shift kit just by adjusting the cable tighter or even disconnecting it and fixing it to a wide open throttle position."

A340 Transmission issues and FAQs - Pirate4x4.Com Bulletin Board

 

[Eicca]

I think that quote applies to the A440F as well. When I adjusted my kickdown cable, I got it a little too loose, and it would slip between second and third. So I tightened the cable up again and it made it a tad snappier. I'll give it another adjustment and see what gives.

 

[sledge916]

Kevin

So do you just reuse the original tranny filter or buy a new Toyota one, I heard these were life time but I am not sure, I also read somewhere that NAPA had a tranny gasket for the pan? what ya think??
Sethro

 

[Tools R Us]

Kevin

So do you just reuse the original tranny filter or buy a new Toyota one, I heard these were life time but I am not sure, I also read somewhere that NAPA had a tranny gasket for the pan? what ya think??
Sethro

Didn't replace the filter, it was very clean, the pan, everything, just slight dust on the magnets. I don't like pan gaskets, bolts tend to come loose, the gasket tends to split/leak. Just stuck it back on with silicone RTV, zero leakage.

Thinking about going further, removing the valve and shimming the spring or replacing with a slightly stiffer spring. Would require some measuring to be sure it wouldn't cover a port, etc. But, I'm happy with the improvement, so have had the "need".

 

[greentruck]

Very interesting.

As I was reading, I kept thinking "What is the difference between the Power button and this mod?"

Once done, do you still have the two settings, Power and not, just both firmer?

Signed,
Generally Mystified About Auto Trannys
;p

 

[josharre2000]

Very cool Kevin!. Adding this to the list of things to do.

 

[dnp]

I bought my truck with 180,000 miles, and I have NO prior maintenance records. As such, I was advised by a former Toyota tech that he would probably refrain from doing a dran/fill on the tranny. Since this valve body adjustment would entail performing that same procedure, anyone have an opinion about a partial cleaning of the tranny fluid on a truck that, possibly, has the original ATF?

 

[Michael Hanson]

If the trans. oil is red and not burnt smelling, I would drop the pan and change the fluid. MIke

 

[JohnR]

Are you sure he didn't mean the 'power flush' style system that loves killing seals, DNP? I wouldn't see why replacing the fluid and filter on a high mileage vehicle would be anything but beneficial?

Tools, after 18 months, do you still believe this mod (vb adjustment) to be worthwhile? Have you noticed any finicky shifting or anything like that since doing the mod?

 

[Tools R Us]

Still happy with it, lots of miles, trails and zero issues. If anything would shim the spring tighter.

 

[Tacoma4life]

Several months ago I tensioned the tranny cable and got a huge improvement in shifting. I first did one full thread on the adjusting nut and it was better, then tried a second thread, better yet. I tensioned the cable a third thread and thought it was ok, but after a week decided it was shifting to firm/harsh, so I backed it off a thread back to 2. It now drives great, and downshifts when it should. Before, even at only 1500-2000 rpm's, you'd have to put the pedal to the floor to get it to downshift. Now it easily drops a gear when needed.
Anyway, if anyone is contemplating tensioning the cable a bit, don't hesitate. All it takes is 1.5-2 thread turns. And to keep yourself from losing track you can put a mark with a sharpie on one face of the nut.

 

[Tools R Us]

... It now drives great, and downshifts when it should. Before, even at only 1500-2000 rpm's, you'd have to put the pedal to the floor to get it to downshift. Now it easily drops a gear when needed.
...

On the ECU/solenoid shifted trans (USA '93-'97), the cable only adjusts the progressive pressure regulator, shift firmness. The ECU determines when it shifts, the cable has nothing to do with it.

 

[Kernal]

Other than personal preference is a firmer shift (to a point) better or worse for the transmissions longevity? IDK.

 

[rove_mcanus]

Other than personal preference is a firmer shift (to a point) better or worse for the transmissions longevity? IDK.

Although a softer shift might slip the clutches and brakes more, a harsher shift increases shock load on the mechanical bits, and pressure on the hydraulic system.

I don't think there are many people who have an educated opinion on the matter. I just sit on the fence and say stock is the best as given the history of land cruisers, they tend to favor longevity over performance.