What are your motivations for this mix n match? The NV4500 is not a wholly better transmission. My buddies seem to keep having to fix, and re-fix their NV4500s.

Used Getrags seem to be getting more common again. Rebuild parts are available on eBay and Rockauto.

 

I definitely think anything is better than the Getrag. The NV4500 is pretty stout as long as the 5th gear issue is dealt with and if your towing heavy alternate into 4th to keep 5th in place. The nv5600 is the best choice for guys that either tow heavy or tow long distances. I've had a total of 4 Getrag trucks and only one wasn't a complete waste. When I tow im normally in the mid to high 20K total gross weight so it could be I just am pushing its limits where most haul a 2k lb trailer with a 3k lb car on it and thats it. My Eager Beaver alone weighs over 6k lbs before I put a tractor or truck on it. Getrags have never worked for me.

 

I think Getrags get a bad rep because of improper set up. If you read Mysteryman's posts, the NV wasn't really a better choice, it was just a more readily available unit.

I like the G360s, set them up tight, overfill them, and they will work for a long time.

 

I'm with BHD on the Getrag. Mine have worked long and hard. Another was right effed up from day 1 (previous owner). I'm just about to do bearings in one now, and my buddies have been through their NV's 3+ times now. 5th gear addressed early, followed my 3rd gear, input, and mainshaft breakages. I haul heavier (up to 12-14k# gross), more often, than they do - not 20k# mind you. That's going to wear out any pickup truck trans fast.

An MDT trans and clutch will put up with more. Non-OD versions can be quite affordable.

 

If determined to go with the NV4500.... I think I'd buy the correct 2ndgen bell, fork, adapter, and starter.

That way you have a complete Getrag setup to sell somebody for rebuild (auto/manual swap?), and recoup most of your cash outlay.

 

After using the junk Advanced Adapters sells for the Getrag to NV-4500 swap bell housing and other associated parts I would agree. I found the AA parts pretty low quality in comparison to OEM parts.