Hey everyone. There seems to be quite a few people who are knowledgeable on the 4r100
I have a question about these transmissions. Why do different trucks shift so differently?

I have a 2001 and a 2003 that doesn't lock the converter until 3rd gear, so the way it shifts sounds similar to a 5r110
I have another 2001 and a 2000 that locks the torque converter in 1st gear, so its not as comfortable when shifting. It puts power down a bit better but when towing its worse in my opinion.

Only possible difference I could come up with the trucks could be that the latter trucks have forged rods and the former trucks have powder cast rods. So maybe once they changed that they started using a different shift pattern?

Thanks for input.

 

It all depends on what tuning is being run. Are these still on stock tuning?

 

There is A LOT to unbox here so here's the long, drawn-out response to your initial concerns.

Ford made a metric ****-ton of calibrations for the 7.3L from 1995-2003 and very few of them actually made any sense for shift scheduling and torque converter clutch apply/release strategies. These shifting and torque converter apply/release points are based on accelerator pedal position and vehicle speed (1995-1997) with a few modifiers for acceleration rate/time in gear for 1999-up. In 2001, FoMoCo finally got their heads out of their rear ends and started making calibrations that do what they should have been doing since day one. Your description of the torque converter clutch apply in first gear has me a bit confused though since even though the tuning is supposed to command a first gear TCC apply under VERY heavy accelerator pedal ONLY, it really can't since there is another section in the tuning that inhibits TCC apply until 24 MPH so you really have to be hauling the mail in first gear to EVER experience that. 2nd gear is another story though as it will apply the TCC at 50-60% accelerator pedal position at higher speeds (so pushing it pretty hard) so while empty it's super-rare to ever even experience that unless you're doing some stoplight drag racing or burnouts for distance.

The 2000 (provided the tuning is stock and the PCM is the original one) will shift differently than the later ones. Normal acceleration will be 1st, 2nd, 3rd, and then the torque converter clutch will apply right at the 3-4 upshift between 36 and 45 MPH. Depending on the calibration, the torque converter clutch will stay applied in 4th until the brakes are activated, the accelerator pedal is released, or after 12 straight seconds of deceleration - ALL of which are stupid and nonsensical modes of operation. The 2001 (again, stock/original) will go 1st, 2nd, 3rd, TCC apply between 35-40 MPH, then 4th at 45-55 MPH. The torque converter clutch will stay applied regardless of APP, brake, or decel time up to 31 seconds (which is a pretty long time).

I will get to more of the idioms as questions/more information on driving style is given.

 

It's also a shame they never made the 4r100 downshift automatically when braking too like the 5r.

 

It CAN. Just not with stock programming.

 

Any downside to having a downshift added?
Something I am considering asking my tuner......mainly for my tow tunes.

 

https://rumble.com/v5a94ut-4-3-downshuft.html

6% grade with exhaust brake.

 

didn't realize I had an Account for Rumble, until I tried to register

saved that info for future use

 

Awesome....how would one convey that to a tuner? (I want a downshift at 45mph?)

Nice 400 btw....sounded great!!

 

Nice boat anchor. 335s are JUNK! I got $700 out of it though after sitting in a shed for many years!

 

The individual transmission calibration engineer programs the shifts. Usually one person would have one engine/trans combination. So one person would have the transmission calibration for the 7.3L diesels, another would have the 7.5L, etc. Some were better at their job than others. Some should not have had that job at all because they had NO CLUE about what they were doing.

From 1993-1997 I supervised the section that calibrated the OBDII parameters for transmissions for all Ford US products. I knew all of the calibration supervisors and most of the calibration engineers. I kept lobbying my boss to transfer me to the E4OD calibration section because I believed I knew how to fix these calibrations. Some of them were HORRIBLE! It didn't work. I didn't get that job. They person that did get it did an admirable job fixing the issues. If I remember the timing correctly the new person took over with the 1999 model year.

 

It takes a fair bit of time to get the shift timing right (don't want to cross upshift speed and downshift speeds because it's like crossing the streams on the Ghostbusters' proton packs) to get it to function. A couple MPH off in either direction makes it not work or get into an up-down-up-down situation.

 

Well said

 

Yes stock tuning

 

All of the trucks are stock

Yeah i noticed it locks in 1st when i have the truck matted. If i accel with a 70% it usually wont lock until the 1-2 shift
The newer of the 2 trucks (late 2001 and the 2003) will stay unlocked under full throttle (when empty) until 3rd where itll lock up in the middle of 3rd gear like you said. The older 2 trucks will lock in 1st gear and stay locked under full throttle.

Yeah what you said for the 2000 sounds spot on, very strange that the converter unlocks when you hit the brakes, seems counter-intuitive. Thanks for the info.

So pretty much I'd be able to tune the truck to however i want to shift it with a good tuning. Interesting. Very insightful thanks again