Does this make sense?

[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 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).

Just took a look, my code is VDH5. Does that tell you anything?

I would also still like to know if the 3-4 shift can be cleaned up without changing the 1-2 and 2-3 shifts.

Would it be best just to call in before filling out the order form?

[cj45lc]

I'd give them a call just to make sure you get all your questions answered. That was one of the things that really impressed me, no matter how dumb or trivial the questions I asked I got great answers without being made to feel like a dumba$$...lol. They are really a great outfit to deal with.

[cleatus12r]

VDH5.

You should have a 1st, 2nd, 3rd, TCC apply, 4th gear pattern. The torque converter clutch will release momentarily during a 4-3 downshift and there will be a 2nd gear TCC apply if you stand on the accelerator above 16 MPH.

Sounds to me like you're feeling the torque converter clutch apply as the "undetectable" shift. The 3-4 upshift will drop a lot of RPM....that's normal. If the 1-2, 2-3, and 3-4 shifts are firm, then I would say that the transmission has been violated.

Sounds like you have an aftermarket valve body in the transmission and a stock torque converter.

[rammertide07]

Never had problem with the pcm casing causing randon shutoff. What I did was put cord holders along the side of the PCM casing to "snake" the cable through. That keeps tension on the cable and holds it in place.

Only problem I have found is the little solder joints on the end of the chip. Slight vibrations and and removing/installing the chip have caused the sharp solder joints to scratch some of the PCM circuits that lead off where the chip slides on. For this, I put some liquid tape over those solder joints so they are not so pointy.

[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.