i know absolutely nothing about the C-6 transmissions

i have one in my 85 F250

i notice that it has absolutely no engine braking whatsoever

it just coasts as if its in neutral when you let off the accelerator, will not slow up the truck one bit



is this how they are supposed to be ?

i really dont like it at all

i had a really bad first experience with the truck when i bought it due to this

a rear wheel cylinder was blown and i didnt know it til i went to stop and it wouldnt stop

long story short i almost made it over the top of a downgrade for a couple blocks and it would have been a really super bad thing because there is no way to slow down without any engine braking, shutting off the key in drive or any other range does nothing to slow you down at all,

luckily i happened to be parallel to someone's yard that had a steep embankment going upwards away from the road, i yanked the truck over into that to stop it.

so that i didnt keep going down the street and down the grade to the T intersection that was at the end

and of course the parking brakes dont work


its a really bad deal



learn me about this

are they supposed to have engine braking or is there something not working right in mine ?

it seems like the older ford auto trannies like these allow the engine to return to idle speed when you are driving

no resistance at all

i remember years ago riding in the back of a '70's auto trans equipped ford pickup and remember the engine returning all the way back to idle when the driver let off the pedal no matter what speed or gear

so im thinking they were all like this ?


in the '77 F150 4x4 also with a C6 tranny i havent even noticed it, but ive only driven it a couple of times and i was trying to pay attention to other things at the time, like the rear axle i just re-assembled and the 351 bottom end i put together as well

hmmm

thanks

 

an auto trans is for going, not stopping. it is not like a manual trans that has gears and a direct connection to the engine through the clutch and will therefore slow you down when off the go pedal.

an auto trans is a hydraulic connection. no go pedal, no connection to the engine.

 

Ever hear of a torque converter? It couples the engine and the transmission both power on and coasting.

Auto trans are required to have engine braking. It's a Federal Motor Vehicle Safety Standard.

Does it have engine braking if the shifter is in 1 or 2?

 

the torque converter is nothing more than a hydraulic pump.
an automatic trans will not give the type of dynamic braking like he is used to with a manual trans.
that is why i "dummied" it down a little by saying it that way.

 

More or less. A hydraulic pump can pump in either direction. So can a torque converter.

You "dummied" it down so much that you made it wrong. An automatic trans does have engine braking.

I have measured the difference in engine braking in an automatic with a lockup torque converter in both locked and unlocked conditions (note that the C6 does not have a lockup torque converter) . When the torque converter is locked there is about 10% more engine braking than with the torque converter unlocked.

This tells me that there is something wrong with the original poster's trans. There is engine braking with a C6, unless something is wrong with it.

 

Could be fluid level problem or something with a servo. Could be something in the fluid pressure control system too.

 

If you have no engine braking at all then some possible problems are:
improperly adjusted linkage
bands may need adjusted
servo leak
damaged oneway clutch
cooked drum

Those are pretty much all the possibilities aside from something in the valvebody.

Matt

 

I'd go with damaged one way.
Autos do have engine braking. even with the old fashion torque coverters. I was showing my son what NOT to do on ice and pulled it down to 1st and got some really good braking.

mike

 

hmm well this is sure interesting


every old ford automatic trans truck i have been around or in has bene this way

i have evne been riding in the bed of an old 70s c-6 equipped ford truck and everytime the driver let off the gas pedal no matter what speed he was going the engine would return all the way back to idle speed


i really confused here


i figured it was how the(C-6 anyways) ford auto trannies were and was normal


so it is not ?

remember i am used to turbo hydramtic GM trannies in which keep rpm way up at a given speed to within a few hundred RPM

so

linkage or band adjustment ?

how do i check those on my 85 f250 ?

it has an edelbrock carb in it, 1406

i have disconnected the kickdown rod thing that runs all the way down to the trans- a few months after i got the truck

it had no engine braking before i disconnected it

also when i dropped the pan and filter on it to change the fluid and such, i took all the wrong bolts out of the filter and plate and dropped the whole entire thing and messed up all the linkage in there so i dont think the kickdown would work anyways

it was a major mess and PITA


i am no ford person at all

on gm tranies there is none of this to deal with

so i didnt know what to expect or what bolts you were supposed to pull on these c-6's

i learned the hard way but its too late now


now recently when i had the car trailer loaded down with 5020lbs of scrap metal the truck would not pull it worth a crap, it could barely move it even 20 feet the trans wouldnt do it, it just sat there the trans couldnt connect enough and put out the torque to the driveline/axle to get it moving

the truck i pulled the load 40 miles to the shredder with('79 chevy C-20) weighs about 4k and so that leaves the trailer empty weight to be around 3k



empty it does just fine


if theres something internalyl wrong with this trans from the sounds of it then im gonna have to part and scrap the truck

ill pull the HO 351 and take the rest of it to the shredder

i have to get 700 out of it which is what i have in the truck

i can get aboiut 350 loaded down out of the truck at the shredder, maybe a hair more with more scrap in it, and about 100 for the edelbrock, and maybe 250 out of the engine it does run very smooth nice strong

plus good more parts like the radiator and a/c parts and glass and so on

thanks for any more info


i have a feeling that the trans must not be all there in this case

hmm

i will have a hard time admitting it though

it sucks

 

Yeah, that transmission was probably mechanically un-sound in the beginning. Needs a overhaul to check what is what on the inside.

 

yeah apparently so hmm

it was an old farmers truck and pulled 5th wheel at some point as well judging by the threaded big hole in the middle of the bed floor and the huge really super thick steel plate across the chassi under the bed floor

and the DMI bumper


i always assumed C-6 trannies always returned to idle when you let off the gas in drive coasting


looks like i was wrong and apparently alot of folks are driving auto trans ford trucks with bad tranies that they are unaware of

hmm


crazy :O

thanks!

 

Mark howdy there

that i am unsure of

it definitely doesnt have any braking in 3rd


i assumed that all three gears should have braking and that since 3rd definitely does not that neither 1 or 2 would as well


regardless if 1 or 2 do have any braking is the trans still messed up if even 3rd alone has no braking effect ?

like i said i have sene many of these trucks with no braking in 3rd gear

so i assumed it was normal for fords

if it really is not normal then there are alot of ppl that i know or have seen in person that are or have run around with the same problem in their trans

thanks

 

ok so all three gears should have braking effect ?


not just 1 and 2 ?

but 3 as well ?

right ?

no ?


thanks!!

 

yes, third will has some effect, but like i said in the first post, it is not like a manual trans.
it should not freewheel, but if you let off the throttle in traffic, it will not cause an accident fron getting rearended like it will with a manual trans.

 

yes i know and realize this trust me i have owned billions of manual trans trucks and so on, and no auto trans brakes like a manual trans does when the clutch is engaged


i just need to know if zero resistance/return to idle speed in gear driving down the road is normal for the old C-6 trannies

in which i have always seen occuring in such trucks over the years and they drove fine

if a c-6 trans is doing this then is there something wrong with it

if so then bye bye truck it is going to the shredder


thanks!