[wood4heat]

I recently started a thread "tough question " to try and figure out if my '03 7.3 had a shift kit before ordering a PHP chip. I think I was wrong in what I was feeling. There are four distinct shifts, with only four gears that can't be right? I figure what I'm feeling as firm shifts are actually the torque converter locking up in each gear. Now can anybody tell me if this is normal, The 1st lockup or shift is very firm as is the second. The 3rd is undetectable unless I'm watching the tach and the 4th is the hardest of all with the largest drop in rpm's.

Is this normal for stock, with a shift kit, an aftermarket torque converter, or just wrong?

The dealer that sold me the truck said the previous owner had the trans rebuilt but they couldn't tell me anything about the rebuild.

Thanks again!

[Longshot270]

Your going to feel the first shift (1-2) because of the large change in RPMs. The second shift (2-3) is usually subtle. The third shift (3-4) is usually very hard to detect. As you stated the last one, the torque converter locking, is the most noticeable with a major drop in RPM.

This is for my gasser truck but I seem to remember my dad's powerstroke being similar. His has been bone stock and very well maintained. I usually see a drop of around 200-300 rpm for each shift and then a large drop from the torque converter locking.


It is nearly impossible for, at least me, to know if you have any transmission upgrades without being there. Without hard numbers the words you use to describe it are just opinions. One person may think 3 minutes after a set time is late while another may consider 30 minutes late. The word late describes the situation but can be interpreted differently. I'd look underneath very closely and see if there are any signs of modification. Things like bolts and screws having chips or corners being smoothed from being torqued would be signs that parts have been removed before. They do not guarantee any modification but it will at least tell if they have been touched. Otherwise you'd have to just ask the previous owner or have someone take it apart who would know.

[wood4heat]

Wow great info!

I tried to describe the 1-2, 2-3 shifts and 4th TC lock as feeling like an 8" or 10" sub bumping behind my seat. Not harsh but positive and obvious.

The dealer who sold me the truck told me the trans has been rebuilt but couldn't tell my by who or what was done. I'm just hoping to get an idea of whether it had a shift kit put in it without having to open it up.

[TwinTurbo]

Have you crawled under and looked at the transmission? I put one in my truck that came out of a friends, that had been rebuilt, it had a tag on it from the company and I was then able to call them and find out what they do in a typical rebuild. Just a thought.

[cleatus12r]

wood4heat, what is your PCM code? Longshot270 had some really great information there, but as far as the 4R100 is concerned it is a little off....

Under normal acceleration, the TCC is commanded to apply in 3rd gear at some point (Depending on PCM code, which is why I asked for it).

If you can truly FEEL the 1-2 and 2-3 upshifts under normal acceleration, it's likely you have something done to the transmission. Typically, with stock programming and a stock transmission, the 1-2 and 2-3 upshifts SLIDE into gear and you really don't notice much of an RPM change.

[wood4heat]

Originally Posted by TwinTurbo

Have you crawled under and looked at the transmission? I put one in my truck that came out of a friends, that had been rebuilt, it had a tag on it from the company and I was then able to call them and find out what they do in a typical rebuild. Just a thought.

Not closely, I'll give it a good look over the weekend.

Originally Posted by cleatus12r

wood4heat, what is your PCM code? Longshot270 had some really great information there, but as far as the 4R100 is concerned it is a little off....

Under normal acceleration, the TCC is commanded to apply in 3rd gear at some point (Depending on PCM code, which is why I asked for it).

If you can truly FEEL the 1-2 and 2-3 upshifts under normal acceleration, it's likely you have something done to the transmission. Typically, with stock programming and a stock transmission, the 1-2 and 2-3 upshifts SLIDE into gear and you really don't notice much of an RPM change.

I'll look for the PCM code as well. You can definentely feel the 1-2 and 2-3 shifts under normal driving, the next shift slides in as you described.

[ToMang07]

I have a little bit of a hard shift from 1-2 only from a dead stop, but I'm pretty sure it's just the TC locking, the tranny shifts VERY smooth the rest of the time, tons of power and no slip.

[wood4heat]

So I crawled under the truck yesterday evening and spent 20 min wiping away road grime but didn't find a tag or any identifier left by whoever rebuilt the trans. I also looked for the PCM code and had no luck there either. It was a long day and I didn't have the energy to pull the pcm.

I don't need the code to order a chip do I?

Also since my 1-2 and 2-3 shifts are solid would it be possible or even recommended to leave them alone and firm up the 3-4 shift with the chip?

At this point I'm wondering if I should just leave the trans tuning alone and do a valve body later. At least then I would know what I had.

[ToMang07]

Originally Posted by wood4heat

So I crawled under the truck yesterday evening and spent 20 min wiping away road grime but didn't find a tag or any identifier left by whoever rebuilt the trans. I also looked for the PCM code and had no luck there either. It was a long day and I didn't have the energy to pull the pcm.

I don't need the code to order a chip do I?

Also since my 1-2 and 2-3 shifts are solid would it be possible or even recommended to leave them alone and firm up the 3-4 shift with the chip?

At this point I'm wondering if I should just leave the trans tuning alone and do a valve body later. At least then I would know what I had.

Yes, you do need the code. All you need to pull the PCM is a 7mm and a 10mm socket. Remove the 10mm harness from behind the fire-wall, (under the master cylinder) then remove the 2-7m bolts holding the black box that secures the PCM.

Turn it to the right and remove.... reverse to re-install.

The Code should be on the plastic cover where the chip will go, and on the end of the PCM that plugs into the harness.

And from my experiance... DO NOT use the black box to re-mount the PCM... mine was turning the chip causing random shut-offs and no-start. Removed the box.... no more problems.

[907DAVE]

One thing I do with mine is to remove the box and use that small grounding tab (on the lower 7MM bolt) to keep the PCM up against the firewall. This also acts as a case ground for the PCM.......whether its necessary or not - I could not tell you.