Engine/Transmission (1994 - 1998) NV4500 vs 5600

[hsmith]

Just curious. Is sixth gear in the 5600 the same weakling as fifth is in the 4500?

 

[Cumminsman]

if you are asking if the over drive gear ratio is the same. yes. is the 6 spd trans tougher than the 5 spd. in my opinion the 6 is tougher. the 6 spd doesn't have the same problems as the 5 spd. like the fifth gear nut, and fifth gear problems. hope this is what you were asking. later, nick

 

[SMorneau]

first is the same as first.

Fourth is the same as fifth

fifth and sixth are the same.



I hope the 5600 is stronger it cost me $4500 bucks to convert. So far I feel it has been worth it but if I have a failure I may change my mind. I would not have another 4500 unless I got a real deal.

 

[hsmith]

Originally posted by Cumminsman

if you are asking if the over drive gear ratio is the same. yes. is the 6 spd trans tougher than the 5 spd. in my opinion the 6 is tougher. the 6 spd doesn't have the same problems as the 5 spd. like the fifth gear nut, and fifth gear problems. hope this is what you were asking. later, nick

What I meant to ask is od in the 5600 a weak link as od in the 4500 is.

Thanks, hsmith

 

[hsmith]

Originally posted by Cumminsman

if you are asking if the over drive gear ratio is the same. yes. is the 6 spd trans tougher than the 5 spd. in my opinion the 6 is tougher. the 6 spd doesn't have the same problems as the 5 spd. like the fifth gear nut, and fifth gear problems. hope this is what you were asking. later, nick

In respect to pulling a heavy fiver, can the 5600 od handle the load where the 4500 cannot?

 

[Groover]

OD weak?

I do not know from experience as I have the 4500 and have had no problems.



Word on the street is that the 6 speed does not have a problem with the OD as the 5 speed does and it's 5th gear nut loosening up. Other than shifting problems (hard shifting , synchros etc) I have not heard of any trashed 6 speeds. Sounds like NV solved the OD problem when they developed the 6 speed.



The problems with the 5th gear nut on 4500's seem to come from pulling heavy and the engine vibrations induced by lower RPM pulling eventually loosening the 5th gear nut and by - by overdrive. I pull heavy from time to time but am carefull to downshift to fourth rather than let the engine lug. My magic number is 1800 RPM I will not let OD RPM's fall below that number and I do not "floor it" at anything less than 2000 RPM's. Either it works for me or I have just been lucky. My dad's 5th gear failed at 30,000 miles but he also will pull at 35 MPH in OD for some reason.



I think you are good to go with the 6 speed (from what I gather).



My . 02 Hope this helps.

 

[CumminsPower98]

For those talking ratios I need to point out that 1st and reverse are slightly lower in the 6-speed. Overdrive is also slightly higher in the 6-speed. Direct of course will always be the same in any transmission. Overdrive in the 6-speed is much stronger then the 5-speed because its on the mainshaft in the main case rather then an extension out the back with a nut holding it together.



See the ratios here: http://dodgeram.org/tech/transmission/nv5600_spec.html

http://dodgeram.org/tech/transmission/nv4500_spec.htm

 

[Texas Diesel]

I think you are asking if the OD gear fails in the 6sp like the 5sp has been know too.



Answer: No. The 6sp OD gear is pressed on with a 40 ton press, none have failed to my knowledge. The syncros are a different problem, but seem to be much better in the last year.

 

[RT66DOC]

Aside from the larger 1 3/8 input shaft change they made around 2000, does anybody know the differences between the '99-'02 5600 and the '03 up model?

 

[TJMoor]

I had a 99 3500 dually that lost the pocket bearing between the input shaft and the main shaft. . NV5600 -- made a mess of both shafts, and the 5-6 sycro assembly... But this trans was an early one, with the smaller input shaft and smaller sycro rings...

This is the only failure I have heard of , other then major power abuse. .

5600 needs special lube ,,, and is very important , regular 80-90 gear oil is to thick for close tallerance and will over heat , cause bearings to shell out...

my 2. 5 cents. .

Terry