Torque Converter - need some help - low/ medium/ high stall?

[E-350]

Hey guys

as you can see in my other posts I went from a droning noise and replacing bushings and u joints over to pulling my transmission and rebuilding it myself.

Transmission is now cleaned up and ready for disassembly, but I asking myself which specs I should look for when getting a new torque converter.

I'm reading a lot about stall speed and I already "learned" from other posts stall speed is no real spec, get it so far. High stall seems to be for performance acceleration, bringing up the oil temp and so on.
But
a) I can't find any rpm for my stock TC and
b) I still don't fully understand which way I need to go in terms rpm.

I would for now just say "go with a HD stock replacement". Used to work for now, so why make changes.
I guess this part number from Oregon Performance Parts would be close to stock?!?
PDQ-4R70W-1L

But perhaps you can help educating me a bit and tell me in which situations I would see which difference going low, medium, high stall.

Vehicle Info:
- 2006 E350
- 270k miles
- 5.4l Triton
- 2WD
- 6" Weldtec Lift
- 35's
- Diff regeared to 4.56

Use:
- 2WD, so nothing too crazy :-D
- a lot of forest roads, some steeper grades
- no rock crawling for sure, but don't mind if it's getting rougher and might grab my winch and pull me over something

[carringb]

Go with stock stall speed. A higher stall speed will let the motor soon up a little quicker and make the van quicker from a stop. But it’ll generate much more heat then the T/C isn’t locked. A lower stall speed will reduce slip and therefore temps, but will reduce torque to the wheels at launches because the engine won’t me able to build RPMs as much initially. You generally only reduce stall speed if you make changes to motor to increase low-end torque output.

[E-350]

Ok, so I had the same gut feeling :-)

Brings me to the question:
How do I find out my current/ stock stall rpm?

[carringb]

I think I found it once in a ford parts catalog. Like the old paper one. This was way back when I hit 200k and I was worried I’d need to swap mine too (based solely on how soon pickup hits were were replacing them) but turns out I never needed too. Still on the stock trans now at 500k miles. Maybe the right parts counter person know how to find it in the current database?

[E-350]

Will try to find the part number and go from there. The OPT states their med stall is at 1.600-1.800.
Sounds fairly reasonable and close to stock I guess. At least based on what I was reading up to now it’s in a realistic range.

Let’s see. I keep on looking and trying to call a TC shop.

[E-350]

Just ordered my TC from Monster Trans.

Looks like for a stock engine/ trans the 1600-1800 stall is a “direct replacement”.
As I have 4.56 gearing and even more due to my 35’s I got proposed a 1700-1900 stall, that is very close to stock, but balancing the huge tire better.

Changes on camshaft or whatever would also change the final selection.

[carringb]

Yup. Should be a good match. Glad you were able to find that spec!

[Vanimal]

Originally Posted by carringb

Go with stock stall speed. A higher stall speed will let the motor soon up a little quicker and make the van quicker from a stop. But it’ll generate much more heat then the T/C isn’t locked. A lower stall speed will reduce slip and therefore temps, but will reduce torque to the wheels at launches because the engine won’t me able to build RPMs as much initially. You generally only reduce stall speed if you make changes to motor to increase low-end torque output.

Well said Carringb. This is why diesel autos have stall speeds in the range of roughly 1300 to 1800 or more.