Ok, based upon my before and after dyno numbers with a 727 with a low-stall Goerend Converter, and 47RH with lockup, I think I gained about 40-50hp from the switch, and about another 40 hp from timing (514 vs 599)....who would do the swap? Is it worth the hp gain?

 

I would do it, better fuel mileage would be a plus too.

 

I'm assuming you had the converter locked when you saw the HP gain.

I'm curious how the torque plot changed with the loss of the torque multiplication afforded by the unlocked converter.

 

I hope its worth it, Ive got a 91 d250, w/9612v,727(for the moment), 3.07's.... see sig and im currently working on installing a built 48re with pcs controller. My only issue i believe is that locked up in OD with 3.07's ill be turning like 1k rpm at 65mph.

 

now that my trams feels like its slipping iam unsure of what direction to go..

47 or 48rh
built 518
or nv5600



i cant believe with my mods in my sig i cant out pull a stock 06 and get 12mpg[veryma

 

Lucas, I see we have shockingly similar trucks: Same size sticks, same turbo, same exhaust, and both with slightly over sized dually tires. I've been averaging around 13mpg too. I did just get 15.X mpg towing an empty 12ft trailer from VT to Maine, but I was trying to be good the whole way.

I have a feeling it's our transmissions. I know mine is wicked tired and slippery. The tires dropped a few on me, but after I did a 10k tow in big hills, the tranny has not been the same since. Temps were fine, but I think just the high stress wore something out inside....

 

my truck tows 6000lbs miniumum in the mountains almost every day..
with my new tourqe converter it loads up earlier and smokes like a train.and not much more power to the ground. its gtot to be transmission.iam just sick of spending money on this thing and being disapointed . ive had a second gen lift pump on for a while but just recently installed a in cab guage and i cant figure out whats going on with fuel pressure.it flutters bad..ill post a vid later.

 

All I know is that my auto trans got cooked on me back in Feb. It's why I'm now driving this fummins in my sig.

When money allows, there is no doubt in my mind I'm fronting the cash for a 47rh from goerend. I just need to find a core trans first.

 

Ive had the same problem with 2 different 1st gens. One I/C and one Non I/C. Once you get them leak free, gauged up, breathing right , a good constant supply of cool fuel, and the front ends rebuilt they are solid and very dependable/reliable. They are great trucks that are economical and with just a little bit of TLC can be total head turners. So dont give up hope yet.

Oh yeah i forgot, also get the electrical system up to par also lol

 

Wow. Nice thread derail. People love it when you do that.

Back on topic...

JQ, I absolutely think it was a good call. Are the shifts much firmer? Built 47/48 transmissions are known for banging the gears pretty hard.

 

just bought a d250-91.5 w/ rebuilt 518 ( od) cant really tell when it shifts, very smooth but it is noisie hear it all the time up or down shift.It's not any different w/ my horse trailer on., ( trl. 4400 #) Pulled 200+ mi. up dn., mtns. so. e. okla. 13.4 mpg head wind,30-35 mph.

 

JQ its a great idea, your getting the power to the ground better, they can be builet proof setups, better mileage and reliabilty. Im doing this swap now.

[Built 47/48 transmissions are known for banging the gears pretty hard.]

Dosent this all depend on the set up.

 

It does. You can have a trans built to tow and it will shift smoothly, but a trans built for speed (as I assume JQ's is, based on the purpose of the truck) usually bangs 'em pretty good.

 

I think all that depends on the VB/accumulator/servo set-up and perhaps clutch plate selection. The hardware's beefier, but relatively the same.

I'm in the midst of completing the build of an NON lock-up 48RH with billet/alloy input and intermediate shafts for my mess.

 

It actually doesn't shift that bad for full line pressure, and full manual. Even with full throttle locked shifts, it feels about the same as my Nova drag car with a TH400. I made the mistake of shifting part throttle lock-to-lock one time, and I thought my whole truck was going to fall apart on that shift!