5 and 6 speeds
 

Why is it that you hear of fully built 47re's and 48's and so on with the automatics. I never hear anything about the nv4500 or nv5600 's being fully built costing up to 10 grand? are they that tough ? i know the nv4500 had a flaw with 5th gear nut (i changed 2 of mine on my old dually) before i read about it in 2004. Just wondering.......

manuals are more heavy duty by nature. you don't have the slipping of clutches and bands between gears that make an auto work smoother.
there are some problems sometimes with manuals, like the 5th gear nut. really in a manual, you only need bigger parts, like input shafts, clutch etc., not the cryo billet stuff you end up getting for autos.

Manauls are a tad more heavy duty than the autos as already stated.

HOWEVER...

Way back in 99 and early 2000 you could build your NV4500 and 5600 with billet parts,IF your wallet could stand the cost of them.Those billet parts for the manuals have long since been stopped being made and even now today you will have a hard time just getting factory parts to rebuild a NV transmission.With New Venture gear out of business for a couple of years the factory parts are getting scarce and most now are coming from China.

so how do you build up a NV tranny to hold power besides a clutch?

With the NV4500's you upgrade the input shaft to a 1-3/8 inch,install a clutch and go.

With the NV5600's you already have the larger input shaft so you do a clutch and go.

There is no way to upgrade the NV's anymore than that as they have proved very reliable over the years,thus the reason for the billet parts not being made anymore.No demand meant no market so they stopped making them.

not trying to be a pain in the arse but are they any holding to 600-800 hp? i know its out of my range but just curious. i had a 98 24v w/ the 5 speed and it had a lot of problems pulling 24-25,000 pounds back from louisiana. 2 bobcats inside a big tex dump. it made it to florida but gave out in the driveway.

Put a cooler on your transmission and rear end. I'm sure both were being taxed since you were well over the factory recommended tow rating of about 12-13k

SHEESH!!!!.....
24-25,000lbs is just a touch overloaded for your truck and transmission or as DOT would say...A bit over the GVW!.

You ask if they hold 600-800hp....
I will tell you for years they held up behind many of the high HP sled trucks out there with no issues.It wasn't until recently that many guys have gone to drop boxes and reversers.My truck has gone 771hp and well over 1200 ft lbs of torque and I have had no issues at all.I do have the splined 5th gear shaft and nut and its has been in for 150k as it was done around 70k.

Manuals are strong and cheaper to fix most of the time, unless you have g56, i have had alot of issues with mine. My nv5600 is still going strong!

can you install coolers on manual trannys? HOW?