I've had to start double clutching when i'm shifting into 4th gear because most of the time my tranny whats to grind instead of going into gear and occasionally it wants to grind when i'm downshifting into 3rd. This problem just started happening all of a sudden. Are my synchros getting worn or am I having clutch issues?

 

I don't think that a clutch problem would cause a problem with just one gear. It is probably in the transmission.

 

Will it hurt anything else to run it like that. Is the 4th gear synchro worn out? This truck only has a little under 93,000 miles

 

I don't think that you will do much damage by driving it. Just do as you have been and try to match up the right rpm so it won't grind so much. Have you ever changed the lube, if so what are you running in it now? I installed a new NV5600 in my truck and it wouldn't shift properly, had the wrong lube in it. Installed the Amsoil made for this transmission and no more problems. Been shifting great for about 200K miles.

 

Well I drove the truck for a few hours tonight down the highway and when I got back into town it had no problems shifting. It seams like it only gives me problems it when it is cold?? I've never changed the oil in it since I've had it. I bought new oil for it awhile back this spring but haven't had the time to change it yet but I probably should change it this weekend.

 

I found a lot of junk in my transmission when I changed the fluid. Pull the side plates off and clean out the bottom. Have been told that there was a magnet there but couldn't find it in mine. What kind of oil did you buy?

 

When I changed my fluid last month I found the magnet laying on the bottom of the case. Its like a big refridgerator magnet. I thought it was supposed to be on the side cover?

 

I got some of the Mopar oil. I should have gotten some Amsoil it probably would have been cheaper cause the dealer is really proud of their oil I think I paid $16 a quart there

 

Mine is doing the same thing in 3rd. Only when it is cold. I think it is caused by a bad syncro. I have heard that parts are hard to come by for the 6 speeds. Does anybody know if that is so?

 

My 3rd syncro has been bad for 100k miles or so. Very obvious when the trans is cold but gets better as it heats up. I just pause between my 2-3 shift and do not down shift into 3rd unless I know the rmp's and speed is right. I have been running 6qts of Schaefer (sp) 5w-30 engine oil in it with a sideplate filter from quad 4x4 for about 70k miles. I am going to put Amsoil syncromesh in it next time. Next time I put a clutch in it I am taking the trans to Standard Transmission and Gear (they are fairly close and I dont know anyone else that will touch it). Bearings, syncros, and seals are no problem to get for these transmissions, but gears and shafts have been really hard to find. If you run it 1qt over full you will without a doubt increase the life of the nv5600.

 

Westexhunt how do you over fill it ? the only thing I could think of is parking on a curb with the fill plug on the high side our taking the top off but that dosent sound like much fun.

 

It's a snap to pull the top off, and the easiest way to overfill it that I have found. You can also fill it thru the top bolt on the PTO cover, but for only about a half qt.
Sounds like the original poster could use a lube change/upgrade. I run Redline MTL and its great except when it gets cold outside, then I get cranky shifting until it warms up. I also think the synchros could be wearing out. I had a lot of yellow metal flakes and dust when I changed out the stock "lifetime" fluid at 60K. Amsoil is also a good bet according to those who run it. Kurt

 

It takes a few minutes to pull the stuff around the shifter and the top off, but it's quicker than rebuilding the trans, and much cheaper.

 

Mine was doing the same thing at about the same mileage. I switched to Redline MTL (not overfilled, only four quarts) and the problems is completely gone. Shifts great in all gears 20K later.