transmission gurus... help out. i found this is it normal?

[F 150Cobra]

found this on the other site

Noticed this today

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I'm driving down the road and I notice when I back off the throttle, the converter (I guess) unlocks and my engine rpms dropt to idle (even if I'm coasting at 60mph)? Is this normal? I've never owned an autotrans that did this.
91 F250 Crew Cab
E4OD tranny
460EFI


my tranny is doing this also ... the rpms drops at idle when coasting in overdrive but overdrive off it stays at high and slows the truck down like engine braking, is it normal with these trannys?



Some guy replied:

Nope not normal at all, my concern would be lubrication at speed. The pump is driven by the motor, not the drive shaft. So you let off the gas at highway speeds and the motor and pump drops to idle speed while the drive shaft continues to spin everything in the tranny at the higher RPM's from the high speed you are still traveling at.
Granted it has no "drive" behind it (load) and it is only during those short times but is it really getting enough lubrication while you "roll" along?
Knowing what I know about the E4OD, I'd have to go with a "no" it does not.

You likely have a coast clutch issue or a TC lock up solenoid issue or both. I'd check the wiring between the computer and tranny and if that all tests OK I'd suspect the computer itself, if it is a tranny or wiring issue the computer should give you a code for it. It's not giving you any tranny error codes with this type problem makes it somewhat suspect in itself.

The speed control itself may be faulty, It may simply not know how fast the truck is moving at different times.
How is the upshifts? harsh 1st to 2nd? and or late or very late shift/s?

 

[BKW]

found this on the other site

I'm driving down the road and I notice when I back off the throttle, the converter (I guess) unlocks and my engine rpms drop to idle (even if I'm coasting at 60mph)? Is this normal? I've never owned an autotrans that did this.
91 F250 Crew Cab
E4OD tranny
460EFI

my tranny is doing this also ... the rpms drops at idle when coasting in overdrive but overdrive off it stays at high and slows the truck down like engine braking, is it normal with these trannys?

Some guy replied:

Nope not normal at all, (Uh huh...Yeah right!) my concern would be lubrication at speed. The pump is driven by the motor, not the drive shaft. So you let off the gas at highway speeds and the motor and pump drops to idle speed while the drive shaft continues to spin everything in the tranny at the higher RPM's from the high speed you are still traveling at.

The speed control itself may be faulty, It may simply not know how fast the truck is moving at different times.
How is the upshifts? harsh 1st to 2nd? and or late or very late shift/s?

In 1932, Plymouth introduced "Free Wheeling" which in some respects is what Overdrive later became.

In O/D, the RPM's drop, which is exactly what it's supposed to do.

In O/D, there is less engine braking. Out of O/D, engine braking is normal.

Cruise (Speed) Control only kicks in at a certain speed, on some that's about 35MPH, just about when O/D also kicks in...so when the speed drops below that range, both O/D and cruise becomes redundant.

Some guy replied..."Not normal at all."

Seems normal to me...

 

[F 150Cobra]

i told the guy and he said :

Safety standards in 1932 where a lot different than they are now, they learn from mistakes. "Free wheeling", the engine not having full control over vehicle speed at all times is not considered safe at any speed. They know that now, in 1932 cars where still a relatively new idea. They used to think safety belts where unsafe to use, cars where built solid so they had no give for safety, now they have crumple zones. And the list goes on.....

It is not normal.


Oh and the Jasper reman, warrantied for 3 years/unlimited mileage, 2800 bucks worth of E4OD I put in my 94 has never done what you describe, so what you're saying is it was bad from the get go huh?

 

[john112deere]

I don't drive many automatics, but Mom's '94 Explorer with the A4LD would drop down to about 1000 rpm if you took your foot off the gas in OD.

And it was still going (barely) at 140k when she got rid of the car, which may be close to a world record for an A4LD so I doubt there was anything wrong with it.

 

[Old_Paint]

I guess I'd have to ask if it were safety related, how come manual transmissions are even still available? I mean, pushing the clutch in disconnects the engine completely from the drive train (which that guy said was some sort of unsafe condition?). Knock it in neutral and coast if ya want. The only way the vehicle is NOT under control is if the idiot behind the wheel inside the cab is not in control.

My understanding of AOD's with locking converters, as well as E4OD, is that the locking TC just disengages at zero throttle and allows the vehicle to coast (freewheel). Then, if you throttle up again, you'll see the NORMAL high RPM until the TC locks again. It isn't like lubrication is lost, because the TC doesn't stop turning. A large majority of the fluid used for lubrication and hydraulics is just dumped into the pan via pressure regulator anyway, so the lubrication theory is bunk. Just because gears/bearings are turning faster, does not mean they need more lubrication than they already get at idle speed. The main reason for the fluid is to provide friction between two relatively isolated mechanical systems, sorta like the clutch disk and pressure plate in the manual transmission. The majority of the flow of that oil is through the TC and back out to the cooler. Some is diverted as pressure for hydraulic control of the shifters and bands.

All that said, though, what you should find is that engine speed drops to a FAST idle, not normal idle speed of 765 RPM. Normally somewhere around 1300-1500 RPM. This helps with the free-wheel effect, and also prevents engine stall, and prevents TC clutch hammering.

I too have a manual, and if I clutch at speeds above 20 mph, the RPM will not drop below 1200. This is particularly noticeable when I down-shift and use engine braking, which I do more than the actual brakes anyway. There is a very noticeable step in the braking effect once the truck slows to less than 20 mph. This, of course is controlled by the ECM holding the IAC open until the VSS indicates low enough vehicle speed to lower to idle speed.

 

[BKW]

i told the guy and he said :

Safety standards in 1932 where a lot different than they are now, they learn from mistakes. "Free wheeling", the engine not having full control over vehicle speed at all times is not considered safe at any speed. They know that now, in 1932 cars where still a relatively new idea. They used to think safety belts where unsafe to use, cars where built solid so they had no give for safety, now they have crumple zones. And the list goes on.....

It is not normal.

IT IS NORMAL!

QWIST ON A BICYCLE, UNDER WHAT ROCK DO THESE IDIOTS CRAWL OUT FROM?

ANYONE WITH HALF A BRAIN KNOWS THAT WHEN IN OVERDRIVE, THE ENGINE RUNS AT A LOWER RPM.

ANYONE WITH HALF A BRAIN KNOWS THAT WHEN IN OVERDRIVE, ENGINE BRAKING IS LESS.

ANYONE THAT TELLS YOU DIFFERENT HAS NO FRIGGEN BRAIN AT ALL!!

I'VE OWNED DOZENS OF CARS/TRUCKS WITH OVERDRIVE SINCE 1956, ALL DO THE SAME DAMN THING.

THE WHOLE PURPOSE OF AN OVERDRIVE TRANS IS TO ALLOW THE ENGINE TO RUN AT A LOWER RPM TO INCREASE FUEL MILEAGE. IT ALSO SAVES WEAR AND TEAR ON THE ENGINE.

 

[Fellro]

Some people... if what he claims is accurate, then the old non-lockup trannies are also unsafe.... also, at what point is it finally safe for the lockup to disengage so you can stop without killing the engine? Some of these vehicles cruise at barely above their base power band, so when you let off, of course it will free wheel a bit. Sometimes, a tps can make it more noticeable, but it isn't unusual. What is bad is when you let off, it goes to idle, and when you step into it, the motor has to rev to get back to engagement.

 

[timdavis]

OK, so it free wheels but occasionally it won't lock back up. Step on the throttle and rpm goes through the roof (2000 before I let off). Then I get the flashing over drive light and it shifts hard until I drive it for a few minutes. I replaced the engine speed transducer already.
I am driving a 94 F250 7.3 turbo Indirect injection with 260000 miles. This is my 3rd tranny because i used it for construction for 5 years. The truck is now a camper towing vehicle.
any help would be greatly appreciated.

 

[blacksnapon]

OK, so it free wheels but occasionally it won't lock back up. Step on the throttle and rpm goes through the roof (2000 before I let off). Then I get the flashing over drive light and it shifts hard until I drive it for a few minutes. I replaced the engine speed transducer already.
I am driving a 94 F250 7.3 turbo Indirect injection with 260000 miles. This is my 3rd tranny because i used it for construction for 5 years. The truck is now a camper towing vehicle.
any help would be greatly appreciated.

That one will have an issue. First step is electronics diagnosis, because of the flashing o/d light, then you go from there.