Well I traded the 01 in for the 03 today. Everytime I shift from 2nd to 3rd it makes the ole grinind sound, but if I double clutch it all goes well. Is this normal?

 

no does not sound normal, mine does not do that. All gears go in nice.

 

Do you have the service history for the '03? Wonder if the tranny fluid was ever changed. I have found by switching over to synthetics made a world of difference on how the NV5600 shifts. Use either Redline MTL or Amsoil MTF. I'm running Amsoil MTF and very pleased with the performance.

MikeyB

 

My 2004 6 speed grinds just a little when cold. However, once it warms up it is just fine. Its my understanding that this is normal. Truck has 12,500 miles on it.

 

My 05 does the same thing. Was really bad when it was new. Try and take just a half second longer to make the shift. From what I understand second and third are on different shafts and one has to slow down to match the other before it will shift smoothly. If I take a little longer than normal on the shift mine goes in just fine and it clears us as soon as it warms up.

 

How many miles on the '03? You might have a synchro going bad. Make sure the trans has new Castrol Syntorque oil in it. You should be able to bang shift every gear if the trans is broken in properly.
Along with waiting to shift a little longer, try shifting really fast. You might find it goes right in.

 

Mine was kind of stiff to shift for the first 10k or so. Now it shifts a little rough from 2nd to 3rd (not quite a grind, but a couple bumps). It has under 30k, and Redline.

 

I have an '03 6 speed and it still is a little stiff shifting but I think it is just the nature of the beast. I did change my gear lube to Penzoil Syncromesh at 12K and it helped some.

The smooth double clutch shift might warrant a check of the hydraulic fluid level in the clutch system.

 

Thanks everyone, it has 70k on it and still under warranty, so I may take it in and have them look at it.

 

The explanation i've heard, any number of times is, that it is a massive transmission for a pick-up, with larger than normal gears & it takes awhile for the synchro's to line everything up so that the shift can take place, smoothly.

That's one of the reasons for using the proper GL rated gear oil. There needs to be some friction in the oil. If it's too slick, the synchro's take longer to slow things down so that a smooth shift can take place.

My own experience with an aftermarket, very high quality gear oil was that it did shift slightly better. Some folks have been using RedLine MTL ($7.00/qt., if you shop around) with great results. I may try that next.

I recently heard that the NV-5600 has been used in some smaller Freightliners.

Joe F.(Buffalo)

 

Factory fill is synthetic. With respect to the NV5600, everything I've read is that it has a lifetime fill of oil in it. I certainly don't buy that. I don't think the dealer will change it out on warranty based on some stiff shifting - they'll probably say that they are all like that.... yada yada yada.

I changed my tranny oil the first time around 18k and it was the best thing I had done to the truck. It had been shifting notchy (especially going into 3rd) for a few thousand miles by then. It made world of difference - and I should have changed it out earlier.

Poor shifting could also be due to the clutch being out of adjustment; but I'd change out the oil first. I've used both Amsoil and Redline (whats in it right now); next time I change it Amsoil will go back in.

 

"I recently heard that the NV-5600 has been used in some smaller Freightliners."

We had this discussion in another thread. I said it wasn't true to my knowledge. Can you give me a model and engine ?

 

Mine is rough until it warms up and then gets better, I have almost 16,000 miles on her now, it seems to be getting smoother. I have heard the same thing on 2nd and 3rd being on different shafts. I think its pretty normal....Just my 2 cents