So can you lock the torque converter and let the transmission shift itself, or do you have to manually shift the transmission if you lock the torque converter?

I'm thinking about this kit for towing myself. I understand how 4th gets things overly hot when towing, but I'd still like to keep the torque converter locked once things are rolling along. Because gosh does the truck drink gas when towing in 3rd without the torque converted locked up, as it does with the overdrive disengaged in stock configuration.

you have to be in manual mode for torque converter lockup, lockup in 1,2 only works in 2nd on the column...from what i can gather anyway.

Here is the feedback I got from the guy selling the kit. This may help. Looking for a consensus from you guys. What do you think?

Depending on how you use the manual control it could be either better or worse for performance, longevity and mileage. Obviously it would be bad for all three of those if you tried driving on the highway at 70mph in 2nd gear. On the benefit side you could gain performance, longevity and mileage with proper shifting techniques, since the factory control can't possibly factor for every variable you encounter in every day driving. Though you may see slight mileage increase, particularly by using the torque convertor lock whenever you're cruising, often the change is not drastic so I don't want to promote that as a selling point; the performance and control should be the main points.

Thanks for your interest and let me know if you have any other questions,

Brett
--
brett@AWshifting.com
AWshifting.com

On 9/8/07, Bill and Dodie <wwoods@rochester.rr.com> wrote:

I have a 93 T100 SR5 3.0 4WD automatic. Would like a little more info on
how this works and what it will do for me mileage wise. 3.0's are dogs
but bulletproof. Got a big tranny cooler on it now and do not offroad
but do tow some weight occasionally. What does this do for tranny wear?
Have 160K on a very well kept truck, just looking for more performance,
longevity and mileage.
Thanks for the time. Bill.

Okay. Think I've come up with an alternative to the AW Shifting box (and should cost a lot less than $130).

The idea is four double-pole, double-throw (DPDT) switches mounted next to each other (perhaps on the console or dash) -- all with toggles initially flipped down. This would connect the top set of contacts on each switch to the center set on the diagram below.

Flipping the first switch cuts the two selenoid wires from the ECU to the tranny, and hooks them to the next switch's center contacts. With the toggle still down on the 2nd switch, you get 12v to the #1 selenoid, and 1st gear. When you flip the 2nd switch, it hooks both tranny selenoid wires to 12v (fed from the top contacts on the 3rd switch). When you flip the 3rd switch, it cuts 12v to selenoid #1 and feeds 12v to selenoid #2 from the 4th switch. Flipping the 4th switch cuts power to both selenoids, causing a shift to 4th.

Conversely, flipping the switches back (starting with #4, down to #2) would sequentially shift back thru the gears to 1st, and flipping the first switch would revert to ECU control (regardless of the other switches' positions).

On the bottom half of the drawing, I tried to lay out a circuit for push-button engagement of the converter lock that would be cancelled automatically by tapping the brakes. This circuit could be installed by itself to control the just the converter, as it operates totally independent of the manual shifting switches.

Anyone out there care to check my homework/comment before I hack into my wiring harness?

(As stated earlier in another thread, this will almost certainly trip a code, as the ECU on later models checks for both continuity to the selenoids, and "proper operation" -- meaning correct gear, lock up, etc. of the tranny. As I now have a ScanGuage II in my truck, I can reset the code instantly anytime I want, so this is not a big deal to me.)

I'm interested to hear what y'all think...

[img][image]http://i218.photobucket.com/albums/cc29/whizkidder/A340ManualShift.jpg[/img][/image]

the solenoids are activated momentarily...may have missed where that was all planed into it, from what i understand there is a bit more wiring than just a few momentary power sources, i was tempted to open up the box and see what i had in there but didnt, miss my truck right now, put in a big old 28" core flexalite aluminum radiator and now waiting for custom hoses... <img src="/forums/images/graemlins/frown.gif" alt="" />

I like the separation of the torque converter locking function. That makes it much easier for someone to do just that wiring modification if they wish. This is one I might actually get around to trying myself. I like your thinking of wiring it to the brake light to cut it out. I've lived with an electrically actuated overdrive, and I was constantly forgetting to disengage it when I should.

I'm less enamored of the bank of switches for the transmission shifting. I can see someone easily flipping switches down, not understanding that it's a sequential type of shifting. What about a double pole rotary contact switch instead?

Good work, none the less!

The Rotary switch would have been my first choice also, but I can't find one with the correct pattern. Anyone have a source?

Any good electrical supply store should be able to help you out with that switch. (not a home center)

I checked my copy of the FSM last night. While there is a clutch for locking up the torque converter, there is no indication of why they designed a combo of a clutch and a slush box. In the early days all autos were slush boxes, basically a fan turning a fan. Then they went to locking torque converters at a designated low rpm and remained locked until you were basically stopped. Now we have clutches electrically tripped to lock and unlock. I guess I do not understand why that is. Suppose the reason is for mileage concerns. I understand the de-clutching going down hill although I am not entirely in favor of it. What I do not understand is the reasoning for a disengaged converter under normal driving conditions, which I believe is the case.

Is there anyone out there who can shed some light on the actual operational events of these trannys and the reasoning behind such thinking?

My tranny (ECU) unlocks the converter any time it shifts from 4th to 3rd, or vice versa. I'm sure they programmed the ECU this way to eliminate a harsh, tire chirping shift (smoother operation on the road). Since there is usually less of an RPM differential between locked and unlocked in a given gear that there is between gears, the converter clutch lock-up gives you much less of a jolt. I'd also be willing to bet that the tranny is specifically designed to prevent a really rapid converter lock-up (restrictions in the fluid passages, etc.), further smoothing the transition.

Shifting the tranny with the converter locked up would be almost like shifting a manual (and dumping the clutch) without ever letting up on the throttle. (Actually, the shifting clutches in an auto don't operate nearly as fast as dumping a manual clutch, but you get the idea.)

My gut tells me that shifting an auto with the converter locked has to be harder on the shifting clutches and bands in the tranny (forcing more slippage during the shift). Unless you have a specially modified valve body that provides for increased fluid flow (and reduced clutch/band engagement time), I'd be very careful about shifting with the converter locked (or at least get way out of the throttle during the shift).