automatic transmission failure question

I guess the 700R4 was the one they stuffed a 4th gear overdrive in. What a piece of SHIT! GM ate the car. I got out of the car and bought another Dodge minivan.

OK, I get your point. If I can split hairs, the fluid drive's hydraulic clutch was less lossy than a Dynaflow.

Very true. Up through the 80s, everyone said "Chrysler transmissions never break" even if they hated Chrysler products. After the 41TE fiasco, the rumor is "Chrysler transmissions always break." People even said that about the truck transmissions that were still the same old design that "never broke" from before.

Both the GM 700R4 and the Chrysler 41TE (minivan transmission of the

90s) are case studies in what happens when accountants "go over" engineers' work and find ways to "save money." I'm sure you can find a similar story at all manufacturers. In both cases, the basic designs are fine- as witnessed by the fact that the 700R4 (and its electronic version, the 4L60E) as well as the 41TE are now reliable... once all the "cost cuts" were undone.... Hot rodders and muscle car guys even build up 700R4s with updated parts and put them behind HUGE engines and they don't break. The 41TE is still in use by Chrysler, and you never hear problems about it anymore. In the case of the 41TE, it was also a bit ahead of its time. The first fluids for it didn't work well, and also since its small and light it really benefits from putting the throttle under computer control (most current cars are "throttle by wire") so that the computer can throttle back during shifts, saving the abuse of dumping engine power into the clutch packs while they're slipping during a shift. That change alone has HUGELY improved transmission reliability all across the automotive industry.

Both were lopusy transmissions. But neither had service problems.

The Torquflite was a GREAT transmission., "WAS." You forget in the 70's came "PLANNED OBSOLESCENCE" and the rise of the BEAN COUNTERS running the big 3. Of the 3 CEO's only Lee Iacocca knew ANYTHING about cars and he didn't know much. The focus on building cars at all 3 companies was to make them as CHEAPLY as possible, if they came off the line all fukkked up, have the dealers fix them. Look at 1975. Can you find a car that even qualifies as a "BAD" car from that year? When you made a terrible car, BAD was a step UP. Again it was the age of the BEAN COUNTERS - MBA's designing cars. One asshole ENDED the Fisher body Craftsman's guild. He didn't want to hear from Engineers who he found "ANNOYING." That's when in the board room they decided it was cheaper to pay off lawsuits than FIX their shitty cars. It was more than just a time of greed. It was arrogance in their belief that the American public would accept ANY shit they dished out. What were they going to do, after all, buy a Volkswagen or a Rice Burner???? SCREW EM!

Gee, I liked my Accord! It was a decent car. Um, I also bought it NEW, not

17 years old...

The first fluids for it didn't work well, and also

Yep, I think Fords do this by retarding the timing during shift, not actually controlling the throttle, but still cutting back engine power. You can actually hear this happen. And I have learned to drive my Toyota that way too, letting up on the gas a bit to force the shift to occur during lower power..

There has to be some period of slippage during every shift and the friction parts wil llast longer if that happens with less power flowing through..

Mark

indeed. and it wasn't just simple fix stuff, it was fatality stuff like ford and their exploder rolling and killing people just because it had a flat tire. executives should be in jail, and that company should be fined billions in punantives for that kind of deliberate calculated slaughter.

Simple rule. Change fluid and filter every 24K. They last just fine. UNLESS you are hauling a 65 foot boat. Had a friend who constantly bitched about his Caravan. I asked him what he expected when he was hauling a boat and trailer several times the car's rated towing capacity? I asked him if he added an extra Trans cooler. He asked, WHY?

Reminds me of a story. One of the guys on our stunt driving team had worked as service manager for a Cadillac dealer, and every year this old fart would trade in his cars, and after the first one he'd tell the sales manager to give him low bucks. The guy was angry and asked why. The sales manager told him that the reason was that he put on lots of miles and never checked or changed the oil. The old man came back; "What? You have to change the oil on these? If they are built that poorly I don't want to own one again." He started doing it to Lincolns. The engines were SHOT. He'd put on 75K to

100K a year. Run them almost dry on oil. Ignore the oil light. Traded it when the oil light wouldn't go off any more. PEOPLE and cars.

There was a girl stuck at a gas station with a pretty decent '66 Mustang,

6 cylinder 'secretary special'. Wouldn't start. We had her crank the key, the starter ground, no-go. Spark, yup...gas, yup...couldn't tell the timing without a light, but everything seemed right.

Then my buddy pulled the dipstick...almost right up to the top!!! We asked the girl when she last had the oil changed. "Oh, I don't think it's been changed...I tell the guy at the full-service station to fill it up and add a quart of oil..."

I maintained my composure, but we had to pick my friend up from the ground, holding on to his sides and almost turning blue cause he was laughing so much...she said her father told her to do that.

Its done various ways. They may not have been the first, but the first cars that I knew of that had these "torque management" schemes were the

1993 Chrysler LH series with the 42LE and 3.5L v6, and the same year Cadillacs with the Northstar. I don't know the details on how the Northstar did it but the Chrysler LH only applied torque management on wide-open-throttle 1-2 shifts. It was done by cutting alternate fuel injector pulses (basically running on 3 during the upshift). It was pretty much undetectable.

Later vehicles that still had a direct cable linkage to the throttle used various "torque management" features involving both retarding the timing and cutting injector pulses. My wife's 05 PT does this and it feels for all the world like the throttle is being closed.

Finally there are the throttle-by-wire vehicles, which just frickin' close the throttle slightly- much cleaner and less noticeble in the feel of the car, although I find them more audible. Under hard acceleration, these systems sound very much like a good driver power-shifting a manual transmission. I *think* that TBW vehicles cut power until the transmission's input and output sensors show the correct ratio, meaning that the clutch pack is no longer slipping. The computer then fully applies the clutch and re-opens the throttle. There's virtually no wear on the clutch packs this way since the only load on them while the shift is occurring is the inertia of the crankshaft.

And I have learned to

And with the computer watching the input and output speeds, there really doesn't have to be much or any real slippage. The computer can just quickly apply the clutch a few milliseconds before or after the ratio is perfectly matched as the engine winds down after the computer closes the throttle and disengages the previous gear.

The sentiment may be right, but the logic doesn't follow- For is "doing well" despite the alleged problems with the Explorer. (I say 'alleged' because there's a lot of evidence that the only real problem was/is idiot drivers that drove Explorers like Miatas, and crappy Firestone tires).

Ah, but what about an aquintence..!

Haven't had to in years, but I did have an old 60's firebird that I had to use a breaker bar on once....

rubbish. that's pure gullibility if you believe that. there are absolutely no conditions, ever, under which it's acceptable for a vehicle to roll just because of a flat. AND there are no conditions ever where it's acceptable for the roof to collapse killing the occupants. the exploder had both from inception. they were known problems, and ford chose to proceed on the basis that the exploder was quick and cheap to bring that market, and the margins exceeded their calculated losses from wrongful death lawsuits.

it was a cold blooded bastard that made that call. nothing less than jail time for manslaughter is appropriate for the individual[s] and deeply punitive damages for the company and board that condoned it. it's also a sad indictment when politicians allow themselves to be bought off on this issue too - they decided to sacrifice innocent americans to wall street. the whole thing is an utter disgrace.

OK, smart guy... then tell me exactly what in the Explorer's engineering design is responsible for the problem. I mean if it exists and could have been remedied, then it must be precisely definable and must be a particular engineering quirk or deficiency that other trucks don't have. So what is it? I've never heard any explanation that was satisfactory yet.

A slightly wider stance, better spring loading and a few other things eventually done to the newer Ford SUV front suspension.

well, you're not addressing the cabin crush problem with this question - kind of important if the vehicle rolls in the first place.

but moving on, it's a suspension dynamics problem. part of the problem with leaf springs is that they can have side-to-side movement, not just up and down. add to that a high center of gravity, narrow wheel base and soggy damping, and you have a vehicle that will kick on recovery from one sideways movement /into/ the lunge of the next. the two combined tip the vehicle. and that brings us back the cabin crush problem again...

Granted.

Uhhhh.... NO. Leaf springs have LESS lateral movement than trailing-arm suspensions, typically. They also have inherent anti-roll forces because they don't like being twisted when one side of the car compresses more than the other.

And besides, there weren't ever complaints of Jeep Grand Wagoneers flipping, and they have leaf spring suspensions front and rear. Cherokees have leading arms front and leafs rear, but they do have solid axles front and rear which place the roll center in a less rollover-prone position than independent suspensions do for the most part.

I don't know much about the dynamics of the oddball independent front suspension that 4x4 Explorers of that vintage used, but it didn't seem to cause a problem on full-size Fords.

The old Mitsu Montero had a higher CG and narrower track- where are the complaints there.

"Soggy damping" might be a valid complaint, but I still don't see anything that makes the Explorer distinctly different than countless other similar vehicles with essenstially the same layout- Jeeps, the midsize GM (Trailblazer/Envoy), first-gen Durangos, Pathfinders, Foreskinners, Xterribles, FJ Poseurs, etc. etc. etc.

sorry, that's a misconception. look under the vehicle. see the dampers set at 45 degrees. that's to try adding a damping component to the known sideways problem.

sorry, they can roll too.

and most of those vehicles fail modern roll tests. we use a "j" bend stability test which specifically avoids, the kick back problem i described. in europe, more rigorously and safely, they use an "s" bend stability test, and that's where the problems get revealed. our tests are a fudge. and we fudge our laws in favor of producers, not consumers.