NV5600 - I need help troubleshooting

[MRColler]

I have read a bunch of different posts but couldn’t find a concrete answer for a fix to issues I know others have had or are having.

I purchased a 04 Cummins NV5600 w/176,000. It has a South bend duel clutch and upgraded Hydraulics. As soon as I got it I changed the trans oil and put in 8 qts of amsoil.

I’ll try to be as detailed as possible describing the problems I’m having.

SHIFTING INTO 2nd FROM NEUTRAL
- Once the truck is started I usually cannot shift from neutral into 2nd without putting the stick in a random gear first and even after shifting into another gear its definite not smooth going into 2nd.
- If I come to a stoplight and put it in neutral I have the same problem as above.

SHIFTING FROM 2nd TO 3rd
- in order to not grind gears when shift to 3rd from 2nd I have to slowly accelerate and let the rpms climb to about 1800rpm, then slowly shift and let it fall into to gear. Basically synchro matching. Even if i moderately accelerate it likes to grind and if I let the rpms climb above 2000rpm it likes to grind.

SHIFTING FROM 3rd to 4th
- from 3rd to 4th it basically have to shift it the same was as I do when shifting from 2nd to 3rd although it’s not as bad.

SHIFTING FROM 4th to 5th
- not problem

-SHIFTING FROM 5th to 6th
- there is no problem here but I can’t use 6th if I’m going slower then about 65. If I shift into 6th at say 50 the truck feels like it’s surging

Any ideas what the issue might be? Is my clutch not disengaging, is the pilot bearing bad, is the throwing Bearing bad. This is my first 3rd Gen and don’t know if it’s just something I have to deal with or not.

 

[Wayne M.]

Exactly which grade amzoil oil did you put in?
Was it acting up before the oil change?

 

[Prairie Dog]

Doesn't sound like the clutch is disengaging.

 

[MRColler]

It’s was acting up before the oil change. I put the amsoil in thats recommended by them. Is there a different amsoil people use?

 

[MRColler]

Yeah I agree it seems like the clutch is not disengaging. Is there a fix

 

[petersonj]

It has a South bend duel clutch and upgraded Hydraulics.

Is this the first dual disc clutch you have driven?

There is much more rotating mass with a dual disc clutch (a second clutch disc and an intermediate plate are added) than there is with a stock single disc clutch. This rotating mass needs time to slow during gear upshifts so that the engine speed and road speed are matched for the gear being selected - or at least nearly matched. If not, the synchronizer has to do much more work to compensate for the mismatch of engine speed to road speed - result, grinding and premature wear of synchronizers.

SHIFTING INTO 2nd FROM NEUTRAL
- Once the truck is started I usually cannot shift from neutral into 2nd without putting the stick in a random gear first and even after shifting into another gear its definite not smooth going into 2nd.
- If I come to a stoplight and put it in neutral I have the same problem as above.

With the park brake set, transmission fully warmed up and shifter in neutral, engine running; select second gear and note how far the clutch pedal raises from the floor before the clutch begins to engage (starts to load the engine). If clutch engagement happens immediately, then there may be a hydraulic issue. If clutch engagement occurs after pedal has moved upward a few inches (normal), then there may be a dragging clutch / pressure plate issue or a failing pilot bearing that is trying to latch onto the nose of the transmission input shaft.

- John

 

[GCroyle]

Exactly which grade amzoil oil did you put in?
Was it acting up before the oil change?

Answer Wayne's question about which oil. Specifics beats unknowns.

 

[EricViviano]

This is the correct oil, I run it myself. 8qts is excessive if you do not have larger PTO coolers, etc. I run 6 qts and dump it in from the shift tower.

https://www.amsoil.com/shop/by-prod...omesh-transmission-fluid-5w-30/?code=MTFQT-EA

But from the sounds of it, your going to have to pull the trans.

Just rebuilt mine. eBay has all the parts. Rebuild kit with snychros, small parts kit, upgraded CDX synchro springs, new shifter base. Then $800 in labor from local gear shop for the rebuild. Also replaced shift fork and throwout bearing, and added South Bend HD hydraulics.

 

[ranger 393]

I have used Amsoil syncro mesh since my truck was new and never had an issue. I believe you have a clutch problem.

 

[EricViviano]

X2 AMSOIL SYNCHROMESH IN FRESH REBUILD

 

[Wayne M.]

I agree with a Clutch problem, but we never heard back from the OP.