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Car Forum / Chrysler Cars / March 2008Vehicle feature that I didn't even know existed until I experienced it personally.
I have written about the '95 GC SE that I got recently before but I noticed a strange (to me) behavior that I had never heard of before. On an 86 mile round trip that I do twice a week I usually set the speed/cruise control for 54MPH (55 speed limit) and I noticed that when I was going down a hill and the speed hit 60 that the trans downshifted to help keep my speed down. I had never been in a vehicle before that did this that I was aware of and the '92 Dynasty with the same engine and trans (3.3) didn't do it so it kind of surprised me a little and caused me to do a search and find the section of text I copied and pasted from the allpar site below about new features and driveline changes for '95. Anyway this feature just shows that although some people don't seem to like it much having an electronically controlled transaxle does have its perks as I can remember having to either step on the brakes (which cancels the cruise) or manually downshift going down some hills in other vehicles to keep my speed down. BTW so far by setting it at 54 and maintaining my tire pressures I have a 21MPG average per the mini trip computer. Not sure how accurate it is yet but it seems to be fairly in line with how much gas I have used. This is despite the CEL/MIL being on with an EGR code because I need a new EGR valve assembly as moisture got in the electrical connector and corroded away one of the pins. (The Dynasty didn't have EGR) 41TE Electronic 4-speed Overdrive Automatic - LeBaron Convertible, minivans: An automatic speed control overspeed reduction feature has been added to the transmission control software. It helps maintain vehicle speed at the selected set point when descending a grade. The TCM (transmission control module) first senses that the speed control is set. If the set speed is exceeded by more than 4 mph (6.5 km/hr) and the throttle is closed, the TCM causes the transaxle to downshift to Third gear. Subsequent to the downshift, the automatic speed control continues its normal operation. To assure that an upshift is appropriate after the set speed is reached, the TCM waits until the throttle is opened at least 8 degrees by the speed control system before upshifting to Overdrive again. If the driver applies the brakes, canceling automatic speed control operation with the transaxle still in Third gear, the TCM maintains this gear until the driver opens the throttle at least 8 degrees to avoid an inappropriate upshift. The upshift is also delayed for 0.5 seconds after reaching the 8 degree throttle opening in anticipation that the driver might open the throttle enough to require Third gear, thus avoiding unnecessary and disturbing cycling of the transmission. If the automatic speed control RESUME feature is used after braking, the upshift is delayed until the set speed is achieved to reduce cycling and provide better response. Additional refinements continue on the 41TE electronic four-speed automatic transaxle. For 1995, software changes provide smoother 2-1 low speed, heavy throttle downshifts. Kick-down shifts after a coast- down in Third are also refined. > I have written about the '95 GC SE that I got recently before but I noticed > a strange (to me) behavior that I had never heard of before. On an 86 mile > round trip that I do twice a week I usually set the speed/cruise control for > 54MPH (55 speed limit) and I noticed that when I was going down a hill and > the speed hit 60 that the trans downshifted to help keep my speed down. It's a feature on the LH cars too - probably most car these days. It is generally helpful, but can be annoying in generally hilly terrain as you go down one hill and crest another (if anyone is familiar with hiway 460 East of Lynchburg and Appomattox, VA, that is the exact worst-case for what I'm talking about). Also, if you have the cruise set just below ticket threshold for the straight-and-level, this will put you well over that on a long downgrade. I am in the habit (on two particular hills that I drive on my daily commute) of punching the 'Decel' button 3 or 4 times (drops cruise control setpoint 3 or 4 mph) just before the start of the downgrade to start that downshift earlier and stay safely below the 'get a ticket' threshold, and then to punch the 'Accel' button 3 or 4 times (ups the setpoint 6 to 8 mph) at the bottom for the long descent, then hit the 'Decel' button 3 or 4 times again when returning to straight and level to return to the original setpoint. This will never be a completely acceptable speed control augmentation for all terrains. If they programed it to hold the speed too tight, the constant up and downshifting would be very annoying on minor terrain variations. The way they have them set now works well for relatively level terrain. In constant short up/down hill, the constant shifting is annoying and does not hold speed well; on long grades, it allows way too much speed variation on hills if your goal is too travel just below the speeding ticket threshold on the level terrain using the same setpoint. Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x') >> I have written about the '95 GC SE that I got recently before but I >> noticed a strange (to me) behavior that I had never heard of before. On [quoted text clipped - 32 lines] > (To reply by e-mail, replace the last letter of the alphabet in my address > with the letter 'x') LOL I should have mentioned that while @ 54 the rest of the people pass me like I am sitting still so speeding tickets should be a non issue. The route is just 2 lane with some short slow lanes going up the hills but the strange part is that after tailgating me for a few miles rather than wait 10 more seconds for me to get in the slow lane most people seem to pass me just as we are coming up on one. I guess I am the only one who values fuel savings over small time savings. >>> I have written about the '95 GC SE that I got recently before but I >>> noticed a strange (to me) behavior that I had never heard of before. On [quoted text clipped - 39 lines] > as we are coming up on one. I guess I am the only one who values fuel > savings over small time savings. Well - the feature, with its ±4 mph window is perfect for you. No tickets for 60 in a 50. Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x') >>>> I have written about the '95 GC SE that I got recently before but I >>>> noticed a strange (to me) behavior that I had never heard of before. [quoted text clipped - 42 lines] > Well - the feature, with its ±4 mph window is perfect for you. No tickets > for 60 in a 50. >> snip << Bill, I was stopped by a patrolman on a July 3 a # of years ago for driving too slow. I'd just moved to a small S.C. town. Just left my dad's house and still daylite and hot, and the highway had a limit of 45. Not being in any hurry plus running my ac w/windows up and only going about 40--gonna make a right turn shortly anyway, and about 3 cars accumulated behind, and 'here he came' with his lights flashing. Obviously he thought I was drinking, going so slow plus I was driving w/windows up in hot summer. He mis-accused me of weaving and even reached thru the door to my steering wheel asking what was wrong with the steering on my older, yet esp. nice '57 Chevy. In later years after we became acquainted he admitted he'd never bothered had I been going 50 in that 45 instead of 40! ...or maybe if I had windows down, as he never dreamed that car old could have ac! We actually became friends. s >> I have written about the '95 GC SE that I got recently before but I >> noticed a strange (to me) behavior that I had never heard of before. [quoted text clipped - 32 lines] > (To reply by e-mail, replace the last letter of the alphabet in my > address with the letter 'x') GM doesn't use this feature at least as recently as 2005. I got spoiled by my friend's Concorde which does. nate  Signaturereplace "roosters" with "cox" to reply. http://members.cox.net/njnagel >> I have written about the '95 GC SE that I got recently before but I >> noticed a strange (to me) behavior that I had never heard of before. [quoted text clipped - 8 lines] > East of Lynchburg and Appomattox, VA, that is the exact worst-case for > what I'm talking about). "Grade management" is the general term. My wife's 93 Vision didn't have it originally, but picked it up during a re-flash pretty early in its life (I think the fact that I kept up with firmware updates on that car is what kept it out of the tranny shop until over 150k miles. It can be annoying as you said, but it beats the heck out of what my folks 84 Caddy did: On cruise, that thing would zoom 15-20 mph over the setpoint on downgrades and fall 10 mph below the setpoints on up-grades. The former was because the tall gearing provided no engine braking, the latter was because the HT4100 engine provided no torque :-p 21MPG seems low to me for 55MPH with a broken in 95, 3.3L and properly inflated tires. I have owned two grand caravans, a 1990 with a 3.3L and a heavier 1999 T&C with a 3.8L and both regularly got 26MPH on flat terrain at 55MPH. Maybe this is because of the winter fuel mix that reduces gas mileage? I also do not know what you mean by "properly inflated" tires. Maybe you are using the door placard which I always thought was too low. (I keep my tires which have maximum inflation pressure of 35 PSI stamped on them at 32 PSI.) I have found that our 1999 3.8L T&C can actually get over 27MPG at a constant 50MPH. Mileage seems to drop as speed is increased... Bob >I have written about the '95 GC SE that I got recently before but I noticed >a strange (to me) behavior that I had never heard of before. On an 86 mile [quoted text clipped - 43 lines] > speed, heavy throttle downshifts. Kick-down shifts after a coast- down in > Third are also refined. > 21MPG seems low to me for 55MPH with a broken in 95, 3.3L and properly > inflated tires. I have owned two grand caravans, a 1990 with a 3.3L and a [quoted text clipped - 9 lines] > > Bob 21 is the combined not just the highway. I have seen 25MPG when I reset the mini trip readout while going down the highway. I am on Iowa 89 octane E10 gas so that does reduce it a bit. The current tires are 35 PSI max cold so I can't go any higher than that but I plan to get a set of Nokian WRs soon so I can go higher on the pressures. Thanks for the clarification. I misunderstood that you were only getting 21 on the highway at 55MPH. 25 sounds about right, although I do think you will do a little better in the summer. Bob > 21 is the combined not just the highway. I have seen 25MPG when I reset > the mini trip readout while going down the highway. I am on Iowa 89 > octane E10 gas so that does reduce it a bit. The current tires are 35 PSI > max cold so I can't go any higher than that but I plan to get a set of > Nokian WRs soon so I can go higher on the pressures. My 96 Grand Caravan had this feature. It had the 3.8l motor. I was on a ski trip and had the cruise set and was surprised when it downshifted as I came down a mountain interstate. Overall, I really liked the feature. Mike |
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