Differential swap

carringb wrote:

Wes Tausend wrote:
...

I would have probably blown the cash on a bigger tranny cooler and a Scan-Guage. I believe anything less than 3rd keeps the converter from locking up which means heat. Except for heat, that V-10 should do well on hills between 3rd and 2nd gear with 3:73's. The 4.56's will really scream in 2nd. I think OD is probably out of the question, even with 4.56's, on most mountainous hills anyway. Could be wrong.

Anxious to hear how it works out too.

Wes
...

The 4R100 behind the V10 locks up in all gears, including 1st, under heavy load.

I'm pulling 12-15,000 pounds typically and always pull in O/D, and it rarely has to downshift into 3rd. Yes, 2nd gear at 60-65 MPH is screening, and it sounds great!

Thanks for the info, Bryan. I will take your word for it on the tranny. I guess I haven't seen my 4R100's lock up under about 35 mph (both with 3.73's) and am not sure what else the parameters are. It would make sense that the trucks will reach over 35 mph in all gears if the operator is willing. I'm only pulling about 8k pounds and seldom need to rev it.

I do have a phobia about "formerly excessive" rpms. There was a time in the past when rpm limits were calculated in piston speeds (piston vs wall) and high rpms definitely meant higher piston wear. I know that the V10 is under-square, meaning the stroke is longer than the bore, and I still imagine that sustained high speed causes extra wear, especially in long stroke engines.

But somewhere along the line when I wasn't looking, piston speeds must have safely increased, because newer engines (metallurgy?) do now often run at increased rpm apparently without excessive wear. Your accumulated truck mileage is a good example of V10 durability, and it does not sound like you've babied it.

dodge_guy wrote:
I can tell you that with 4.30`s you won`t drop much out of 3rd on anything but the steepest of hills. and with the 4.56`s you may actually be able to hold 3rd on the steep hills. And to really take advantage of the new ratio, get a tuner from 5 star to recalibrate the shift strategy. Fords programming sucks, the 5star tuner really makes it tow great!

dodge guy,

Thanks for the voice of experience. With my lighter TT (8k), I only drop to 2nd once in a great while around ND with my Excursion. But it might be pretty common to hit 2nd in the SD Black Hills, or mountainous regions. It already seems like 2nd is then a bit too low, even for 3.73's, but there is no intermediate gear between it and 3rd. Since 2nd sometimes already spins the rear tires, 1st is way too low, unless one has 4x4 engaged to spread the traction.

My buddy has an extended cab 2000 F-250 and pulls a 5vr closer to 11K with 3.73's. He shifts to 2nd more often than I, even occasionally on the ND I-94 if bucking a good wind on a hill. He recently likely overheated his tranny, blew a tranny seal, and lost his torque converter in the Black Hills. I will say that he probably had a hard time maintaining over 35 mph in some of the tight curves, which might have meant the converter was at least not frequently locked up.

One other thing I noted is that my 2000 Ex and buddies 2000 F-250 seem to shift slightly differently when not towing. My Ex seems softer, gentler, something I do not consider a durability advantage. Even my 2000 diesel shifts mushier, although it holds OD well on hills (3.73's). As second owner, maybe my buddy has an internal shift kit and doesn't know it.

Wes
...