Replaced Transmission, do I need to reprogram the computer?

[mennitti]

I changed the transmission, flushed everything. It seems to work harder like it is in a lower gear. Also, when stopped and pulling out it intermittently will rev to 2k, I'll notice I'm not moving, then it catches and takes off hard.

The boneyard which has a great reputation insists they used this very transmission for several hundred miles and it was fine. He told me this is common with people that replace transmissions. The computer has to be re-flashed to work correctly, and dealerships will tell me that is not true, but to insist they do it or I will ruin the transmission.

I've talked to two garages and both insist the 2003 4.0 with the 55s transmission (with dipstick) are not electronic and can not be programmed.

Any ideas?

 

[JuBean]

When I changed my transmission last year nothing had to be done for programming and I do not recall reading anything here on the forums while I was reading up on the process.
I could see the possibility of programming on much newer transmissions but what is used in our trucks is pretty simple.
How much fluid were you able to get into the torque converter before it was installed?

 

[2000StreetRod]

5r55e?

. . . I've talked to two garages and both insist the 2003 4.0 with the 55s transmission (with dipstick) are not electronic and can not be programmed. . .

I thought the 2003 Sport Trac with the 4.0L SOHC V6 had the 5R55E - not the 5R55S. I'm not aware of factory produced Fords with the 5R55S that have a dipstick.

Both the 5R55E and the 5R55S/W have PCM controlled shifts, pressure and torque converter lock/unlock. The PCM has limited adapting capabilities and stores changes in nonvolatile memory. Disconnecting one battery terminal and turning on the headlights for a few minutes will erase the stored changes forcing the PCM to utilize the factory default settings. It may take several driving cycles for the PCM to adapt to the replacement transmission.

If you have the 5R55E, valve body separator plate gasket "blow out" is common which results in upshift flares especially after the transmission is warmed up (after driving for 20 minutes).

 

[crankyjew]

I thought the 2003 Sport Trac with the 4.0L SOHC V6 had the 5R55E - not the 5R55S. I'm not aware of factory produced Fords with the 5R55S that have a dipstick.

yepp

 

[mennitti]

This does have a dipstick. The original did as well.

 

[mennitti]

Are you saying drain the battery to reset the PCM?

 

[2000StreetRod]

transmission type

I think you have a 5R55E and not a 5R55S.

You don't need to drain the battery to reset the PCM - only remove power to the non-volatile memory to clear the "learned" adjustments. Some members remove both battery connectors from the battery and then touch the two connectors (not the battery terminals) together to clear the PCM memory.

 

[mennitti]

Okay thanks. I removed the positive and negative leads and touched those wires together.

 

[mennitti]

Still need help.
I took it to a Ford dealership a month ago and had it reprogrammed. It did improve but not fix the issues.

Since I bought it 5 years ago the 4wd low never worked. My flares when first shifting into drive are worse the colder it gets. Could I need to replace the shift control module behind the passenger kick panel?

 

[2000StreetRod]

any codes?

Did the dealer check for any transmission related DTCs before reprogramming the PCM? It seems like the logical thing to do. If so, what were the codes?

 

[mennitti]

The only code was before changing the transmission : PO734 Gear 4 Ratio Incorrect.

 

[2000StreetRod]

manual speeds?

. . . My flares when first shifting into drive are worse the colder it gets. Could I need to replace the shift control module behind the passenger kick panel?

I'm not familiar with transfer cases so can't help in that regard. Does the engine flare when going into reverse? What happens when you start out in "2" and in "1"?

 

[mennitti]

The only problems with the new one is shifting into drive the tack rpms go to 2000 and then it will catch and take off hard, it also flares around 20mph until warmed up.

 

[2000StreetRod]

confirming your responses

Just to be clear:

Did the dealer check for DTCs and find none before reprogramming the PCM?

There is no flare to 2000 rpm when starting out in "1" or "2"

Does the flare at 20 mph occur before the upshift from 1st speed to 2nd, during the upshift from 1st speed to 2nd, or during the upshift from 2nd speed to 3rd?

 

[mennitti]

I don't know. They downloaded an update then reprogrammed. It seemed to work for two weeks, then the weather turned cold and these problems returned.

Correct. 1 and 2 work. Drive will work if i put it in neutral and rev it up a few seconds.

I would say the flare occurs when a shift is supposed to take place. I believe 1st going to 2nd.

 

[2000StreetRod]

which torque converter?

Did you install the torque converter from the replacement transmission, the original transmission or a new torque converter?

 

[mennitti]

No