I am enjoying some new experiences with the latest tunes that Clay sent me for my single shot injectors. I purchased my original DP Tuner chip in November 2006. It seems that some changes in the shift strategies have been made since then. While slowing down to a stop, or making a turn, the trans has a firm downshift, from OD to 3rd at 40 mph while keeping the torque converter locked until reaching 20 mph, then unlocking. I like this feature as it helps in slowing down my heavy truck and will be appreciated more when towing. Also, it sounds kinda cool when it downshifts. I wasn't sure how many people had this trans tune, and if you liked it.

 

My wife has this feature with TW and it makes an auto almost bearable. I think I'll keep my stick though.

 

Mine does the same thing in the 80 hp economy mode, but no in the 60 hp tow mode. It has change my driving habits some because I'm used to coasting up to stop signs/lights, etc. No doubt it will help save on brake pad wear.

 

While I like things that help me "go", I like things that help me "whoa" just as much.

 

I like the downshifts also when coming to a stop. The only thing is, when I drive in a 40 MPH speed zone. I either need to drive above 40 or below 40 to keep it from shifting a lot. All in all, I like it.

 

I don't have the DP, but is "saving the brakes" better than the additional work load cycling on the much more expensive torque converter and tranny internals?

The reason I ask is because I've always sort of enjoyed using the downshift approach with a manual tranny until I got to thinking about it and realized that I'm putting much more wear and tear on the clutch assembly which is much more expensive to repair/replace than the brakes. Having thought about that, I've been watching the instantaneous MPG calcs on my son's Jetta TDI 5 speed for the past couple of months, and have experimented quite a bit with different strategies for increasing the average MPG values.

[Yes, I know that the computer's calculated MPG's are not dead on accurate, but they do have a very consistent trend with hand calcs and I find the correlation to have been quite helpful in learning to drive a little differently and see real increases in MPG's.]

Anyway, when I cost downhill with the clutch disengaged, I have seen a consistent improvement in mileage and know for a fact that the tranny is basically idling, as does the engine during that coasting period. If, on the other hand, I do my downhill driving by just coasting with my foot off the accelerator but leave the clutch engaged, the vehicle does certainly slow down more quickly, but the average MPG's at the end of a tankful of that driving technique is not as high as when I disengage the clutch for downhill coasting.

Just a few thoughts based on 7 weeks of playing around with my son's '05 diesel Jetta with a manual tranny. Perhaps the same principles don't hold as true with our PSD's.

EDIT... although my comments are focused on downhill driving with a manual transmission, and not an auto, the only reason I mentioned it was due to the correlation I've seen with transmission action as compared to mileage, which is an indication (in my mind) of how much work the tranny is actually doing.

 

I like the downshift also though mine shifts at 45 and disengages at 25. Hmmm?

Pete. I am not sure I agree with your statement/question

"I don't have the DP, but is "saving the brakes" better than the additional work load cycling on the much more expensive torque converter and tranny internals?"

Isn't it doing all these same things anyway? Just changing the speeds at which they happen? I may be incorrect. Just asking.

 

I like it - I don't have to use as much brake pedal when coming to a stop.

I agree with the comment about 40 and 45 mph zones. In traffic with frequently varying speeds it does shift in and out of OD a lot. I usually just turn OD off to avoid all the up and down shifts.

 

I agree with you there Rick.

 

Possibly. I guess it really boils down to what MPH ranges you typically drive in and whether or not this DP Downshift program would cause your tranny to shift more frequently or not... sort of like what Rick alluded to when he talked about having to change how he drives to avoid "hunting and searching" by the tranny. If you end up seeing the tranny hunt and search more, then you're going to see more wear and tear on its components.

Also, I guess my earlier comments about the "coasting" and downhill driving techniques really don't apply to this thread at all seeing as it is focused on the actions of an auto transmission, and not a manual one.

 

Mine is at 45/25 as well. I haven't noticed it in 60 tow but is there in 80E

 

Rick has a dually with 4.10's so that is probably why his shifts differently than those of us with 3.73's. I too am at 45/25. The 25 doesn't bother me as much as the 45 one. I didn't like the shift strategies at first because I was used to drifting/coasting when you let off the accelerator, but I have gotten used to it. I am not sure that I like it better, but it doesn't stand out in my mind as much as it had in the past. SO basically I am undecided. I like it, but I'm not sure I PREFER it. If that makes any sense.

 

Mine downshifts at around 45 and I'm mostly happy with it. My only complaint is lots of back/forth shifting on windy roads that have a straight line speed of around 50 and curve speed of around 40. There's an easy fix though- lock out the O/D and motor on

 

Transmission tuning is one of the hardest things to get right, because every single customer has their own preference and driving style. I think it's just about impossible to get trans shifting right on the first try, even if you are the best tuner in the world.

Me personally, I would love for my truck to have the shifting ability of my wife's BMW. She has the Steptronic 5-speed transmission, and the shifting on that is the best I've ever seen. It has 3 different modes for shifting. The normal everyday automatic mode is designed for mileage, and keeps the engine at slightly lower RPM's by upshifting sooner in the RPM range, and delaying the downshifting slightly (yes, the BMW Steptronic does automatically downshift as you slow down, and doesn't "freewheel" like the 4r100 does in stock form). The next mode is the sport drive, where it holds each gear longer to keep the RPM's up, and is much more aggressive on the downshift. I love this mode for driving in the mountains, as it's much more responsive and snappy on the throttle for winding mountain roads and highways. Then the last is the auto stick.

At any rate, I would love to one day have two identical tunes, one with a more "economy" friendly shift pattern, and the other with more "aggressive" shifting, just like the BMW.

When Jody was in town a few weeks ago, I talked to him very briefly about tweaks to shifting, and he is very understanding about this. I think he knows that no two customers are the same, and that transmission tuning takes some time to dial in correctly. In addition, he has done some fantastic work with John Woods over the past few months, and very recently has incorporated some new shift strategies in his tuning. So for anyone looking to update their DP-Tuner shifting, talk to Jody and see what he has available. It seems like he is always coming out with something new and improved.

 

Holy double post, Batman!

Not sure how that happened, I only clicked the post button once.