Moved from another thread

Newby here, don't know how to start a new thread but here goes. Well, now I do!

I've acquired a 1990ish F53 based motorhome. The motorhome modelyear is 90 but I suspect the chassis may be 89 or so with a 7.5l gas and an E4OD tranni. History is that it ran 90,000mi then tranni was rebuilt due to pumping fluid over the side (mech said a "clip" had come loose in the OD unit). Ran a scant further 13,000 miles and the OD failed (couldn't even be pressed apart) so hard parts were replaced and overhauled by AMMCO. Previous owner (old timer) didn't recognize a fault but when asked, he said "yes, it has been that way since AMMCO redbuilt the tranni".

Problem:

While not in OD, in any gear, when descending, engine braking is only available for a few seconds (as if the convertor is unlocking and the tranni is dropping to low pressure/idle mode). If I apply a slight bit of throttle, things lock up and engine braking returnes, as long as I hold a bit of throttle only! Which signals tell the tranni to remain locked up for braking or to remain in high pressure mode?

Suspect: ??????

Can someone provide me with the "pinout" of the E4OD connector and a discription of what signals are to be expected on each wire and wheather they come from the engine side or tranni side of the connector? I have the pinout of the E4OD Diesel connector but none of the other info. I see two solenoid signals, how are they used since the selector is mechanical, or do these solenoids control other than the shift?

ANy ideas where to start trouble shooting this problem? I'm referbing the coach and hope to take it out west this spring so will need this feature when descending out of the rockies!!!!


Larry

You may also respond directly to Larry_too@yahoo.com if you wish.

 

it goes into this coast/semi neutral state when you let off completely so that fuel economy is increased while you let the truck free roll down the grades.if it held you back all the time,you'd use more fuel.
for steep long descents,you can turn od off so she remains in 3rd.that will hold her back for ya while going easy on the brakes.otherwise,let her roll to conserve fuel.

 

Also, keep it out of over drive in hilly areas. A motor home is heavy as hell and overdrive is not meant to be used with a bit of a load. If you find it shifting from 3rd to 4th often, take it out of over drive. It'll save your overdrive clutches.

 

Can be several things however after a "rebuild" and all new hard parts most all of those suspects should be able be eliminated right of the bat. Low pressure, sticky valve/s, worn/burnt coast clutch, worn/burnt reverse clutch, missing check ***** etc.

"Pressure" might be the problem to low throttle closed, reason lightly toeing go pedal slightly does provide engine braking, slightly increases pressure? Might need to take a pressure reading but early for that I'd think.

The fact it works when lightly toeing the "go pedal" tends suggests to me at least and until know more, its fine mechanically just have an electrical problem.

I'd look at the coast clutch solenoid/circuit, the common denominator to engine braking in any gear below OD beyond failed hard parts mentioned above.

Coast clutch is "ON" when selector lever is in manual 1 or 2 range and when OD is off.

Check for stored codes and check throttle position sensors fully closed voltage, make sure its operating within spec, reads smooth throughout range. If for no other reason to eliminate it as cause/part of the problem.

Make sure solenoid pack harness connector, its clean and free of trans fluid. Kinda doubt you'll find a problem there, trans does what its supposed to when receives the correct command (Based on what you said anyway)!

I don't have a book for that model. E4OD service manual does not list "no engine braking in manual third gear" (OD off). But does list the condition for manual first and manual second?
Odd it doesn't list that? I know it'll have engine braking OD off.

See what the computer tells you first, go from there based on info it provides.

It should have a code stored pertaining to the issue, the computer should see it as a problem I'd think.

CCS = BRN-ORG pin 6 ?

 

Just renewing the thread. Still looking for a pin out of the E4OD connector and what signals expected on each pin, and where they are from.

After a few seconds or engine braking, the "drag" goes away and the engine rpm drops to idle. This when OD id out. I suspect the tranni is dropping to low pressure as well as declutching.

Larry

 

courtesy of oldfuelinjection.com

E4OD solenoid pack connector on the upper right.

Pin 1: Vehicle Power
Pin 2: To shift solenoid #2
Pin 3: To Shift Solenoid #1
Pin 4: To Torque Converter Clutch Solenoid
Pin 5: To Coast Clutch Solenoid
Pin 7: From Transmission Oil Temperature sensor (to PCM)
Pin 8: Sensor Signal Return (from PCM)
Pin 11: To Electronic Pressure Control (inside transmission)
Pin 12: Vehicle Power

E4OD Solenoid Chart and MLPS (Transmission Range) info:

courtesy of Steve83

 

Thanks, I'll try to decipher that.

Correct me if I'm wrong:

D cancel means Drive with OD canceled.

ON means voltage present (12v or what ever) (or does it mean pulled to ground so current pulls in the solenoid?)

OFF means zero volts (or does it mean no current flow so solenoid is not pulled in?)

PCM Control means the PCM is providing the signal

In MANUAL, where does the signal to the coast control come from?

Which pin commands high or low pressure and what should I see on that pin when sitting in neutral at idle or when driving?

Laird


Now, from what I described, where would you look?