BobK said:
Hey Rene....thanks for the info.
Did you get a manual for yours?You know,something with an exploded view of the internals?
What exactly did you do to yours and how much did you pay for the parts?
No manual, just pulled it apart about 4 years ago when I first got it...bagged everything and put it away. I got it for nothing but it was a basket case. Was run critically low on fluid, input bearing got red hot, input shaft sheared, 4th gear on the main and 4th on the counter were fragged, 3-4 synchro was fragged.
I had to replace the input shaft (4th gear attached), the entire countershaft, all the bearings and seals, 3-4 synchro assembly and a bunch of small parts. I'm into it for about about $850-$900 US in parts, still need a bell and shifter...
I've found a few online exploded views and parts lists. This is a pretty decent one:
http://www.rsgear.com/NV4500Trans.htm
My NV4500 is a '95 with the 5.61:1 first gear, which also means I have the one piece countershaft. Yours should have the two piece countershaft, semi-useless trivia.
FWIW I decided to use the stock 5th gear nut on mine. The reading I've done points to high input torque and heavy loads being the two largest contributing factors. 5th gear rocks slightly on the splines during the transition from coast to drive and vicy-versy and works against the nut behind it. As you can imagine high input torque and/or a very heavy load would greatly exacerbate this 'problem'. The tranny is rated for 450 lb of input torque. I can't recall the max load it's rated for as for as weight goes, but I think it's in the 12,000 lb range. Most any Cummin's is easily exceeding the input torque rating, and at the crank I'd bet the old 6.5 TD was too.
I don't tow with mine...let alone really heavy stuff and I don't run a bombed CTD, I run a NA 6.2. Lastly, on my NV4500 and on yours there is a vibration dampner between 5th gear and the nut which isolates the nut from any possible loosening.
I did spend some time examining my mainshaft for any signs of fretting where 5th slides on and and found nothing.
I'm currently waiting for two synchro's and then mine can be finish assembled. I'll make sure to snap some pic's if you want at any stage of assembly. PM me if you want any specific pic's...or if you have any other questions.
BTW, you will need a specific socket to remove the 5th gear nut. Plus it's torqued to ~300 ft/lbs...
You can manually shift the tranny into reverse as well as a forward gear to lock it up (so you can undo the nut). You already have the top cover off, so it'd be easy to do. Then you just need to be able to hold the tranny itself from rotating.
Rene
