4R100 tranny

[Mike OB]

4R100 Ford transmission: I hope no one gets intimidated by what I am trying to share.. Please feel free to ask me any thing, there are no dumb questions – just dumb answers. I am going to put this in away you can print it out to help you understand how it works. Abbreviations used by Ford (TP)-throttle position / (IAT)-intake air temperature / (TCS)-transmission control switch / (TCIL)-transmission control indicator lamp / (TSS)-turbine shaft speed / (OSS)-output shaft speed / (TFT)-transmission fluid temperature / / (VSS)-vehicle speed sensor / (TR)-digital transmission range / (BPP)-brake pedal position / (A/C)-air condition / (MAP)-manifold absolute pressure / (BARO)-barometric pressure. Also a idle validation switch on the foot feed. Everything listed to this point is either a sensor or switch or an indicator light, they talk to the (PCM)-power control module. That in turn controls the / (TCC)-torque converter clutch / (EPC)-electronic pressure control / (SSA)-(SSB)-shift solenoids and (CCS)-coast clutch solenoid.
The PCM is programmed with a cold start strategy, This lowers the oil pressure when the engine is cold to soften the shift and it also makes it shift at a higher speeds and delays TCC lock up when cold. The temp of 160 degrees (ECT)-engine coolant temp must be met to remove this strategy. The manual also states that the TFT has some affect on the cold strategy but does not give a temp. or how much effect the trans oil temp has.
The EPC sets the oil pressure in the trans. And is regulated electrically by the PCM. From the way everything is explained in all the information I have gathered temperature is the largest factor in the level of oil pressure. The IAT and the BARO (altitude) have some bearing on the base line setting. The MAP is a load signal and will make the pressure rise as more load is applied. I could not find a normal operating temp. for the trans. oil any where for Ford, how ever I did find that Dodge states that normal temp is 180 degrees. I did learn that Chrysler developed the cold start strategy first and Ford copied it. The TCS and the TCIL are the overdrive switch and the light in the gear shift that shows OD on or off, if this light starts to blink at you, this is a call that the EPC is shorted or the circuit is faulty. The BPP or BOO as sometimes called will cancel the TCC if applied. The TR is the switch, which tells the PCM what gear you have selected. Line pressure for a normal warm condition is P&N 50 – 65 / R 70 – 100 idle and 213 –223 stall / (D) & 2nd 50 -65 idle 136 – 156 stall / 1st 70 – 100 idle 136 – 156 stall. CAUTION IF YOU TEST PRESSURES YOURSELF – DON’T HOLD STALL FOR MORE THEN A FEW SECONDS.
As you can see, there are a lot of different imputes that can and will change the way your trans. will shift. There are after market shift kits that can and will improve shift quality, and there are after market add-on units that will lie to the PCM and raise the oil pressure. This will also give you a better shift. If you have tried the electric add-on units like the Banks Trans command and it didn’t help, then you unit is running in a pre set factory setting which is a safe mode. That means that one of the signals which is needed to ensure proper operation is either missing or not stable. I hope you enjoy and benefit from this post. MARRY CHRISTMAS Mike OB

[F-350MAN]

thanks for the info mike, very helpful, and thanks for takin the time to do the research you've done also....Randy

[shahin214@hotmail.com]

when I go into 4th it shutters until I reach 60mph, so I turn O/D of until I reach 60mph is that normal

[Mike OB]

No that is not normal, it sounds like your torque converter is starting to come apart or you have low oil pressure to the lock up clutch. A scanner will tell you if it is slipping on lock up. Mike OB

[Star Gazer]

I am having a couple things going on I don't think is right. This is besides the slow up shift that seems to take forever to get into the next gear, unloaded around 30-35 mph.

1st, when pulling a small travel trailer around 60-65 and I have it kick out of overdrive on a hill, it will sometimes not want to shift back and the rpm's may get up to 2800 or so. I have to let off the gas and force it it to shift back.

2nd, after pulling fast under certain conditions, like wind or hills, when I get off at an exit, stop, then drive, it will sometimes stick in 1 gear and not want to shift up. I am assuming it is hot so I let it idle a while before turning off. I just did a 1600 trip and it did not do it this time but the outside temps are cooler. This occured both with a 50hp towing chip, and without it.

Anyways, seems the tranny is the weak link in this truck. Is there something I should have looked at, like temp sensors? I had it serviced about 8k miles ago and fluids show no signs of being burnt. I am thinking a gauge package might be a good investment?

Truck info, 2000, F250, long bed, ext cab, 4x4, tow package, 3.73 rear end, 54k miles. (is this even the same tranny as the thread title?)

PS, front end is finally ok after my experience with Firestone.


Thanks,
Dean

[Mike OB]

To put a temp gague on the trans is a snap, there is a plug in the side of the trans that you remove and screw the temp sender into. Banks makes a six gun that gives you exhaust temp plus trans temp's and load. I put a Banks torque converter in mine and I have a BM pan with fins as well as a trans comand which give you better oil pressure. But I pushed my engine up to about 500 hp as well. If you have a bug screen on the front? remove it and see if will stop the problem? I put a bug screen on mine and the trans temp went way up. Better to clean bugs then burn it up. Mike OB

[Ftruck4me]

My trans went pop while picking up speed in 2 n/d gear; then no forward gears would work; but reverse still does.
Could my PCM be messed up??