3FE "Sport Mode" mod

[Eicca]

Given the recent attention to the A343F tranny pressure boost mod, I decided what the heck, I might as well try something I've wanted to try for a long time.

I tightened the kickdown cable as much as I could. The red rubber cap is sitting flush with the adjusting nut and the little bead thing is ~14mm from the red rubber cap.

A definitely noticeable difference. The drivetrain feels a lot tighter. Shifts are firmer. The butt dyno detects a small improvement in torque. The tranny holds gears longer. It takes less foot pressure to get off the line. And the obnoxious flaring when downshifting 3-2 is significantly reduced, plus I don't feel like I have to mash it to get it to downshift in any gear.

Will report on gas mileage

Sent from Montezuma using smoke signals and a spork

 

[mr jits]

You're going to fry your transmission. Constant high line pressures create heat. Heat destroys transmissions.

 

[Eicca]

Tell me more. I'm skeptical about that, since it isn't shift-kit-drastic different. It's just tighter. If I didn't know it was modded I'd assume it was factory. There's no roughness

Wouldn't a shift kit fry it then? I've felt plenty of other transmissions that shifter harder than mine does.

 

[scottryana]

I bet that cable has stretched over the years and you will have to adjust it past the manual's recommended. It happens to cables, mountain bike shift and the old brake cables were notorious for it.

 

[Tools R Us]

You're going to fry your transmission. Constant high line pressures create heat. Heat destroys transmissions.

Really? How much did the line pressure go up? Will the increased pumping heat be higher than the reduced heat from less slippage?

 

[wrongway around]

this problem is with most cables i think , i thought a tight cable just tightend the shifts ,i didnt think it regulated pressure.

 

[Mixelplix]

I'm extremely skeptical of this hurting the trans (gas mileage maybe). It's commonly known among mechanics that hard shifts are actually better for trans life as the heat (the killer of transmissions) is generated during shear. Unless you're towing, the shear comes from the long relaxed shifts.

On another note, I'm also skeptical of using '3fe' and 'sport mode' in the same sentence.

 

[jonheld]

You're going to fry your transmission. Constant high line pressures create heat. Heat destroys transmissions.

I'm going to say no to this one. Line pressure is not what develops heat in a transmission. Heat is developed from slipping torque converter and slipping clutches under load. A change in static line pressure will change how much and when things slip.
If the OP is getting less flare and less slippage and is using less throttle to achieve the same conditions as before the adjustment, then please tell me what is developing more heat.

There are 2 things I would have done differently. First is to make sure that the throttle cable was correct. With the pedal fully depressed, the throttle should be juuuust touching the end stop. This adjustment should always be done first and will effect both throttle position and kickdown cable position.
Next, I would have adjusted the kickdown cable in small increments, not a giant leap.

In any case calling it "sport mode" is a tad optimistic, but I like it

 

[Alleycats]

Sport mode, thats a good one.

 

[bigezvol]

What is this "A343F tranny pressure boost mod" you speak of?

 

[Eicca]

3FEs are sporty, right? Right??

Seriously though, the truck feels SO much better, and I have every reason to doubt this adjustment will hurt it. If it were slamming when shifting from P to D or D to R, I might be willing to consider that, but everything just feels better.

The A343F tranny pressure boost mod is in this thread: "Improving Transmission Shifting."

 

[mr jits]

There is such a thing as too much line pressure, which causes the pump to have too high of a load increasing the heat in the transmission. You also have to keep in mind that the pumps job is to maintain the line pressure so you can in effect rob the transmission of its ability to cool itself if the line pressure is set at too high a threshold.
I'd personally increase in increments rather than on big increase. Look for better shift feel, but stop before you've maxed things out.
Shift kits are intended for certain uses and are by no means meant to be an end all be all "improvement" to a transmission.

 

[CJF]

Seriously though, the truck feels SO much better, and I have every reason to doubt this adjustment will hurt it. If it were slamming when shifting from P to D or D to R, I might be willing to consider that, but everything just feels better.

Everyone with a 3FE should tighten the kickdown cable if it hasn't been done before, and yes, you usually need to go quite a bit beyond FSM spec to get it to feel right. And, it almost always cures the 2-3 rpm flare.

Like others are saying, I'm not sure I would have done it in one big leap (on one of my rigs I actually got the shift points too high for my liking and had to back it off), but it really does make a dramatic difference.

 

[Motleyone]

All 3FE's had an A440F transmission.

 

[Eicca]

I did end up backing it off by about 3mm. I was having to let my foot completely off the gas to get it to upshift. It's perfect now; still feels snappier, holds gears better, and still way less flaring 3-2.

The 2-3 upshift is still annoying. If there's no load on the drivetrain it thunks pretty bad. But the fact that it only does it with no load makes me not too worried about it. Yes, drive flanges are new. And I know I need new u-joints.

Very happy right now.

 

[jonheld]

All 3FE's had an A440F transmission.

Are you asking a question?

 

[Duiser Offroad]

I bet that cable has stretched over the years and you will have to adjust it past the manual's recommended. It happens to cables, mountain bike shift and the old brake cables were notorious for it.

Agreed, this was my initial thought. You might be closer to stock than you know.... Otherwise, too much line pressure can be a bad thing.

 

[CJF]

A few years ago someone posted up a 1991 magazine review (not sure what mag.) of the 80 series right after it came out. One of the things on their (short) list of complaints was that the shift points were too low. I wanted to go back in time and tell them, "Tighten the kickdown cable!!1!"

 

[Motleyone]

Nope. I was just letting the OP know that he most likely does not have an A343F.

 

[Eicca]

Nope. I was just letting the OP know that he most likely does not have an A343F.

I know the 3FE rigs don't have the A343F. But it was the A343F guys that got me thinking.