So I originally had a 47RE, and I bought a NV4500. My plan was to buy the Billet 1-3/8 Input Shaft, a nice double disk clutch, and bolt a NV271 T-Case to it. I use my truck for daily driving everyday with most my miles being city. I tow rarely, and not more than 10,000 lbs. and I take it off road a lot through rocks or what ever I can clear.

Now I am second guessing if I want the NV5600 or not. I know the real only difference is the extra gear of 3 and 4 in the NV5600. I would still bolt a NV271 T-case up to it. But I don't want to be in that situation if I ever do have to tow something around 20,000 lbs and struggle in that rare instance. My truck is not very modded yet but my goals are 500+ HP for it.

I also don't know if there is an upgraded input shaft for the NV5600 since it is already a 1-3/8. Is there anything I should upgrade for either transmission I have left out? I want something that can handle 500+ HP with out a doubt and be reliable.

Which transmission should I drop in?? It's making me go crazy!

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Or even to throw in there a ZF6, which I have looked into a lot... I just want the most reliable transmission at 500+ HP...

 

You bought the nv4500 so run it, I'm a cheap bastard that way . I would buy a clutch like arockyway2go here is his combo "sachs nfw7223 flywheel cost 130ish new shipped to the door, inmotion clutch stage 3 organic rated 400hp and 900tq 12 1/4" disc size for $325 to the door and a 6303-2rs bearing for the pilot bearing 3.89 to the door. So I achieved a $1200 set up for under $500 via e-bay. Good products are out there for reasonable prices you just gotta do your research."
The 5th gear nut is the weak link of the nv4500. The nut loosens after awhile and then the mainshaft bearing starts spinning on the shaft, then you need a new mainshaft.

 

x2 for the nv4500. the 5600 is alot longer and heavier. that'll get u into custom driveshafts and crossmembers and stuff like that. the 4500 is plenty tough (if u fix 5th). just dont skimp on the clutch. my vote is southbend, but im biased because thats what is in mine and i've never run anything else...

 

Im not worried about drive shafts and cross members.. I am going to put a 271 transfer case from a Ford in, which gets rid of the slip yoke. I was planning on buying either a Valair or South Bend Double Disk Clutch. I have no intent of going cheap in any area. I want the best reliable parts out there. Which is why I can make up my mind on which transmission to go with..

 

My cheap clutch has 270K miles on it..... Hmmmmmmmmmmmmmm I have a customer who had to put a clutch every year for 9 years and he would complain that it chatters when it engaged. He also towed 20K behind a cab and chassie with a 454 and a NV4500. The bad clutch that I removed was a LUK. I put in a next generation clutch, LUK pressure plate and Valero disk.. He praised the fact it was so smooth. Booth clutches were organic on the pressure plate side and ceramic on the flywheel side. The difference was the install or break in. The bolts the previous guy used were 3/4 length and not stock. I installed 1 1/4 and torque them to 25 ftlbs. My buddy has a valair and it shatters, I installed it, torque it but did he break it in properly? If you want the best NV5600 then zf6..... Then again real drag racers and sled pullers runs autos, hmmmmmmmmmm. I forgot to say my customer went to a Chevrolet dealer and they told him that a shattering clutch is the way it is

 

I might be buying an NV5600 today for a good price, with less than 40k miles on it. So I will have both the 4500 and 5600 to decide from now. It seem it will be around the same price to install. Considering I would buy the billet Input Shaft for the 4500.

Is the 5600 just as strong as the 4500 with the billet input shaft?
And if money is not a factor here, which should I install, the 5 or 6 speed?

 

both are good trannies and you can use the 271 Allstate gear has either input shaft for the 271 the 4500 in a 29 spline I do have a input for the 5600 if you need one the 6 spd is a little heavier that the 5 spd I personally like the 4500 it is simple to work on and parts are cheap do the 5 th gear fix NV4500 Transmission 5th Gear Repair

remember every time you shift you will have one more shift to do

 

Yea I am definitely going to need to be buying an input shaft for the 271 soon. I don't mind weight, and Rowing one more gear is just a plus to me. I love everything there is about a manual, even shifting. But even if Im unloaded I should be able to skip a gear when driving, like, start in 2nd, to 4th to 5th to 6th. I just like the fact that I have another gear just in case I have to tow something heavy.. plus having 3.55 gears and 37" tires would make it a little nicer.

 

if you need a input shaft for the 271 for the 5600 pm me I have one

I traded my ford 271 for a dodge one that was on a manual 5600 found out that the 4500 and 5600 take diff input shafts so I took my 5600 shaft out and put in a new 4500 the t case had 15k when it was rolled

 

I drive bolth, and 4500 is much more fun to drive empty, and faster. but if you pull 14k trailer or more in hills the 4500 sucks! when i tow my 24k trailer i only use my 6 speed. but also i ask what gears you have. If you only tow 10k or less the 4500 is easy and cheap. remember that the 5600 makes you shift 2 more gears every time you start. my leg gets tired.