I am in the process of collecting parts for my conversion and I am looking for a manuals trans now. I know a two things about the 4500...Fifth gear nut and input shaft needs to be bigger for bigger power. As for the 5600 I know two things aswell...It's a six speed and it comes with the bigger input shaft.

I want to do a good amount of sled pulling and I will be running some pretty good power....Now for my questions....I have heard/read that the 5600 is best for sled pulling, Why? Is the main shaft and output shaft bigger or have better bearing support? Would a upgraded 4500 be just as tough as a 5600?

Or is the 5600 just the KING!

Thanks,
Brent.

 

Info on the 5600,

If you plan on doing alot of pulling. You will have to upgrade your mainshaft sooner or later. Alot of the pullers on here break the mainshafts. You may be able to get 50 pulls out of one or maybe only 2. here so more info on the 5600
https://www.dieseltruckresource.com/...d.php?t=168351
https://www.dieseltruckresource.com/...d.php?t=115143

maybe coaltrain, pourindiesel, or W.F.O. will chime in since they have both broke one

 

Thanks for the carnage reports... I guess there isn't any bullet proof shaft for the 4500 or the 5600? I know about the stonger ones available but I guess they just aren't strong enough. Of course in sled pulling alot has to do with traction and track conditions when parts fail.

So maybe when I decide on a trans and get the best input and output shafts available I'll just buy two since It's a pretty good chance they will fail too!

So what is the difference between the 4500 and 5600 other than the input shaft size and ones a six speed?

Brent.

 

I like the 6speed since you have better gear options, 4th gear, 4-low on the t-case seems to be the ticket for pulling with a 5600.

I don't know what gear the 5speeds pull with.

 

You get 2 choices. 3rd low or 2nd hi. 2nd hi you better have a built to the hill engine and dust the tires or a loose track.

 

 

or 35in tires for 3 low

 

Just broke my mainshaft on my 5600 Last weekend. It lasted me almost two seasons on a stock shaft. Alot depends on driving styles. The Clutch dumpers will tend to break them much more often. In this case mine broke on the big end of the track when the sled bit hard and fast.

 

Don't think that that though hasn't crossed my mind...

Screws up 2nd Hi though, I've thought of going to a 4.10 gear, heck I've thought of lots of things... like a custom cut 2nd gear would be neat.

 

Exactly right. When I broke mine I was running fully block suspension and I knew I should have switched to some travel and to AT's for the pull because the track was taking no prisoners and was sticky as tar.

Advantages of the NV5600 is that you have basically 3 gears to select from. Also the big input shaft is already there.

Some people think NV5600's are weak because they have broke one but the reality is in Sledpulling sometimes something HAS TO GO whether it be an axle, a rear end, a driveshaft, a tcase, tranny etc. It just a matter of what goes first....(kinda like the mob when someone has to go!)

NV4500 is not a bad choice at all for pulling if you are building a truck from the ground up. The advantages will be that you will have some weight savings to the tune of about 200 lbs.

 

Not all of them, 99-00 6 speeds came factory with the 1 1/4 input shaft and the SO engine. I know because I have one. The larger 1 3/8 input shaft came with 01 to 02 and early 03?? whenever they changed to the G56.

 

if you can fuel through the rpms its a good gear.

i would stay away from a 5600 if i was starting on a tranny. i would rather bust axles then bust a mainshaft that you can only fix one time.......

 

Why is the Main shaft only a 1 time replacement part?

Brent.

 

once it breaks you can send it to EEP and they can fix it but then when it breaks again its a nice paper weight

 

Did the same thing this spring. Broke it at the end of track on just the second hook. I've got the eep upgrade but my brother had this same upgrade and broke it. Granted we pull our trucks hard but I believe Hooked you are the one with the orange colored truck and that thing runs good. I'm sure there is a solution to the problem hopefully a heat treated shaft. Redline stated it best probably best to go with a NV4500. You can always change tire sizes to get you the best gear. Granted I'm sure both transmissions can be broke I've just seen a lot more 6 speeds break than 5 speeds. Its better to break an axle or something else rather than a mainshaft in the transmission that can only be fixed one time. You could just put another stock shaft in it but then again its just a ticking time bomb. Its not a matter if you break it but when. Its all in what route you really want to go.