So this problem has been eating away at me for a while now. Ever since I bought this truck almost 2 years ago, it has always had a hard shift problem. It almost feels like the clutch doesn't release fully right away. I figured it was the stock hydro's going out. I replaced them with the valair HD set from DAP. It definitely helped the problem but it hasn't completely gone away. I thought at first maybe the tranny is just starting to wear out being it has over 200k on it, but it feels exactly the same in every gear. I tried adjusting the clutch pedal out farther so it gets more travel and pushes the clutch more. Still feels like the clutch isn't releasing all the way at first. The truck doesn't try to creep forward on me or anything, I just have to hold the clutch in for about 2-3 seconds in between shifts if I don't want to "catch" the next gear hard. Without pulling the tranny, I am not sure what else I can do. Would a worn out pilot bearing/bushing cause this? The clutch doesn't slip or anything yet. I just don't want to wear my tranny out prematurely or whatever. I even replaced the fluid with no change in behavior. Sorry for the novel guys, just don't know what to do.

My SB Con OFE with over 130,000 miles on it will still groan and the truck will vibrate a bit if she's in "too" high a gear for the speed and you give her some pedal until she gets to 1500rpm.  It's the gears/tranny/driveline absorbing the torque impulses (for lack of a better word) of the mighty Cummins.  If it was slipping, you'd be smelling it.

Ok. Whatever clutch was in there before this one had a ridiculous pressure plate so maybe being a this is a lighter pressure plate I can feel it now. Thanks for the thoughts. Much appreciated.

My SB Con OFE with over 130,000 miles on it will still groan and the truck will vibrate a bit if she's in "too" high a gear for the speed and you give her some pedal until she gets to 1500rpm.  It's the gears/tranny/driveline absorbing the torque impulses (for lack of a better word) of the mighty Cummins.  If it was slipping, you'd be smelling it.

 

 

Also, it's the clutch absorbing the torque and then transferring it to the other parts.

this  vibration is  noticeable  when the  clutch  is  engaged?  (foot off the  pedal) 

 

Is  it  an actual  vibration,  or  is  it  a  growling/buzzing  'noise'?   or  both?   

 

dang,   at  1100 - 1400  rpm,      I don't  think  any of us are making enough  torque  to slip  a  new  clutch,  unless  something    is  hanging up.

 

       Check to see if   all the   ujoint  straps  are  tight too,  and  no  cross  bearing caps  have disappeared.

 

I  don't know if this is possible,  but   your  rear shaft is  a  2 piece.    There   SHOULD  be  a   indexing   notch.  which     'times'  the  2  halves  of the  driveshaft.     (at the  slip joint).     If  out of  phase,    there would  be   a  very nasty   vibration...   but you say  yours  goes away!  

 

Ok,  I  re-read your  post  on the   new noise...  and  noticed  you   said

" vibration  @   1100-1400    in   4,5,6th   gear."  (upon  acceleration)   

 

That is  too  low!    the  above   posters  nailed it  with    driveline  growl..    

Even  on  very light  acceleration,     I  don't like to  let the  engine  drop  to  less than  1400- 1500  after the  upshift. 

Especially  in the higher  gears. 

Edited February 14, 201411 yr by rancherman

Thanks guys. I think you were right about it just being to low of rpm's. In the higher gears I just make sure I am up above 1500 rpm's before I try any acceleration. No more vibration!! I just never really had this problem with the old clutch.

I took a trip yesterday of about 1200 miles (yes, 1200) and everything seems to be working fine. I really enjoy this new clutch. Shifts great!!!

Thanks everyone for the thoughts on this. Much appreciated!!

Thanks guys. I think you were right about it just being to low of rpm's. In the higher gears I just make sure I am up above 1500 rpm's before I try any acceleration. No more vibration!! I just never really had this problem with the old clutch.

I took a trip yesterday of about 1200 miles (yes, 1200) and everything seems to be working fine. I really enjoy this new clutch. Shifts great!!!

Thanks everyone for the thoughts on this. Much appreciated!!

Man, you really have confidence in our advice to take a 1200 mile trip! SURE GLAD IT WORKED OUT!!!

I just noticed your tire size and gearing... makes perfect sense now about your 'noise'.

I have 3.55's and stock tires... I intentionally shifted today at 1100, and got your symptoms, but shifting at 1400 all was well.

I'll be purchasing a clutch set up for my 98 pretty quick.. so I'll be shopping!

Depending on what kind of power you are looking for, I would really recommend the single disk valair that I got. Very nice clutch for the money I think. The pedal is seriously almost as easy as a little 4 banger car clutch pedal. It is a little grabby on take off but as long as you dont need to slip it to much its not bad.

Good to hear it is all working out for you. Mine is grabby on launch also. I have gotten used to it but still not fond of it.  

Depending on what kind of power you are looking for, I would really recommend the single disk valair that I got. Very nice clutch for the money I think. The pedal is seriously almost as easy as a little 4 banger car clutch pedal. It is a little grabby on take off but as long as you dont need to slip it to much its not bad.

I'm planning on basically duplicating ISX's set up. ~400??? I'll need to get the right flywheel,

mine is the smaller one for the 5 speed. Plus the starter motor spacer.

my 'yota is really easy to clutch now, (amazing what a little grease in the right place will do)

Too many equate stiff pedal with 'strong clutch'. Not always true, a dry sliding release bearing

takes a fair amount to overcome.

Just had a quick question about tranny fluids for the NV5600. I am looking at changing everything over to synthetic slowly and was wondering what synthetic fluids, if any, are recemmended for the NV5600. What is everyone running or what would you run? Thanks all!!  

Just had a quick question about tranny fluids for the NV5600. I am looking at changing everything over to synthetic slowly and was wondering what synthetic fluids, if any, are recemmended for the NV5600. What is everyone running or what would you run? Thanks all!!  

I  visited  with a  member on  CF  about what he is running in his  fleet of  'hot shotters'.    He  has  about  5 rams  with the  nv5600,  and  about 6 trucks  with the  G56.    I figured  THIS  guy  should  know,  with  the amount of miles  these  accumulate..

 

He  runs    50%   50wt.  and  50%   5w-30.     He added  geno's  cooler,  for a total of  2 gallons  of the blend per  transmission.

He   pretty much  runs   Dello  brand  synthetic,   but   didn't  think   brand  made  any difference.  I  wouldn't   mix different  brands though.

 

I'm  going to  give this  a  whirl   when  it's  time  to  service  mine.     I'm  going  to   just forget the  mileage... and  change it out  every spring.

Our   2000  has  the   oil fill  relocated  for more capacity...  and  will do the same to the one going into my  94 project.

Thanks rancherman. I have been getting more noise out of the transmission lately and I am hoping new fluid will quiet it down. I am sure it is bearings as the noise gets louder as the tranny warms up. The noise stops if you push in the clutch. Sounds like it is coming from right underneath the front seats. I had an old ford ranger with bad bearings inside the 5 speed gear box and drove it like that for years.

 

I guess I will have to get this NV5600 rebuilt someday.... Its always something isnt it?

So when I start looking for clutches..... What is everyone's preference?? I am looking at this maybe. I have no plans for going any bigger on the power side of things than whats in my sig. I am looking to not spend to much, but I don't want to settle for a stock clutch.

I got the South Bend 13' single disc!

Is yours working out better?

Dave

Just had a quick question about tranny fluids for the NV5600. I am looking at changing everything over to synthetic slowly and was wondering what synthetic fluids, if any, are recemmended for the NV5600. What is everyone running or what would you run? Thanks all!!  

 

Whatever fluid you decide to go with, I recommend as do many others to over fill the transmission by 1 quart.  Some recommend 2 quarts:

 

http://highgeartransmission.wordpress.com/tag/nv5600-6-speed-transmission/

 

to ensure the #5 aft shaft bearing gets adequate lubrication which seems to be one of the worst points.  Here is a good read on what goes on inside the NV5600 requiring rebuild:

 

http://blog.genosgarage.com/wordpress1/wp-content/uploads/2012/05/TDR67_MyNV5600.pdf

I got the South Bend 13' single disc!

Is yours working out better?

Dave

It is working out great!! I love having the stock clutch feel but able to hold the power still. It is still very grabby though. You really cant slip it at all without the whole truck shaking with it. Still having a transmission noise problem though. It only makes noise when the transmission is turning. As soon as you push in the clutch the noise stops. Must be a bearing somewhere.... Seems to get louder while in 4th-6th gears going down the road.

Whatever fluid you decide to go with, I recommend as do many others to over fill the transmission by 1 quart. Some recommend 2 quarts:

http://highgeartransmission.wordpress.com/tag/nv5600-6-speed-transmission/

to ensure the #5 aft shaft bearing gets adequate lubrication which seems to be one of the worst points. Here is a good read on what goes on inside the NV5600 requiring rebuild:

http://blog.genosgarage.com/wordpress1/wp-content/uploads/2012/05/TDR67_MyNV5600.pdf

Hi LoveOak,

Thanks for taking the time to put all the posts up.

Yes I will overfill, plan on putting in a street "L" so that should get me to the 2 qt overfill. I will read all, I'm sure I'll enjoy.

Thanks,

Dave

Great information, thanks again, LiveOak!

I get no chatter or vibration w my setup. I can start off easy while towing or not, the clutch is as comfortable as my 4 cylinder Dodge Dakota 5-speed was. Just not quite used to where the shift pattern is, not 2nd nature to me yet!

Dave

I get no chatter or vibration w my setup. I can start off easy while towing or not, the clutch is as comfortable as my 4 cylinder Dodge Dakota 5-speed was. Just not quite used to where the shift pattern is, not 2nd nature to me yet!

Dave

I too  had a  'learning period'.   I did a lot of   2nd to 5th  'jumps'..  (that  was  embarrassing!)  I was used to  a  fairly  sloppy  pattern on  some of my older crap!

    Just  think:     narrow  gates,  and  let the  centering springs  tell you  where  the  middle  gate is!     (3rd and 4th gear)     If you feel no  spring pressure  on the  handle,  you are in the middle gate.   

And  You'll  notice   a  slightly  slower  shift   (the period  of   engaging > successfully,  without 'buzzing'<   the next  synchronizer)  with these  trans.   Guys  that add  a  triple disk wonder why  they notice  harder shifting..  mainly because of the added mass  the  syncro's need to   speed up or slow down. 

 Well,  how many  150-200k  transmissions got  a new life  behind  a  modded  engine and brand new "heavy'  clutch!?   A LOT!      Tired  syncros  are suddenly  required  to  work even harder,faster...

This  trans   has  a huge  rotating mass,   especially for a   full  synchronized  trans... and the  syncro's   are   just a  tad  'light'  for the  expected  duty.  ( especially  the  'duty'   modders    are putting through it!)  

Shift  like  a  civilized  quadraped,   (now,  don't get me wrong,   AFTER  you have shifted,  your  right foot can do anything you want!)   and  that trans  will last   a  LONG  time!       

Edited July 25, 201410 yr by rancherman

Agreed!