I have a feeling I'm getting close to rebuild time on my NV4500HD. It's got over 240,000 miles on it, and when I had the clutch replaced last year, the guy told me the input shaft bearings were toast (as in they fell out, in pieces) and the rest showed signs of significant wear. Very understandable at this age and mileage. He replaced what he could easily get to, and I opted to avoid a complete rebuild at the time, though he said I'd likely need to re-address the situation within the next 25,000 miles. (This is a transmission tech my family has known for years, so there's a high level of trust here.)

So my question is... do I simply rebuild this transmission—effectively returning me to a like-new stock tranny—or do I go with an aftermarket setup of some sort?

My thoughts are: a rebuild will run me less than $1,000... probably more like $850-900. It's lasted this long under some pretty hard (but not abusive) use, and if I can get another 200,000 out of a stock rebuild for that kind of money, I'll be more than happy.

If, however, I can do something else for not terribly much more that will give me a stronger tranny... I'm certainly willing to consider it. At present I'd guesstimate I'm hitting ~250hp/500tq, although I plan to get an upgraded TST fuel plate to get me in the neighborhood of ~300hp/700tq fairly soon. I honestly don't see myself going past that, so I'm not in need of anything extraordinary.

Y'all know far more than I do. What would you do in my shoes?

 

a bearing kit, new syncro's, and dip as many parts in a parts washer as you can will go a long way.

I would also go ahead and get a new slave cylinder if the one you have is still the stock one.

also, if you havent already, tack weld 5th gear so it wont fall off, very common on the NV4500's

 

The 5th gear tack weld has been done. My father in law, the previous (original) owner, did it after losing 5th on a long trip and having to limp home in 4th...

The bearing kit, syncro's, etc etc... is that pretty much what a rebuild would entail? Or would a full tear-down and rebuild involve replacement of more than that?

Thanks for the tip on the slave cylinder. Definitely will do.