NV3500 vs 4500 difference

[hb32]

Are they the same physically as in can a 4500 be put in where a 3500 with no modifications? I realize the clutch would be bigger and trying to do the least possible modification to be able to tow a 5000 lb trailer. Truck is a short bed regular cab with a 305. Mostly short haul with no big hills

[hatzie]

The NV4500 should fit with relatively minor modifications elsewhere.

The case lengths are different.

You'll likely get to move the crossmember.

The shift tower may be further back on the 4500. Whether this translates to sheet metal changes depends on how different it is.

The input shafts are 10 spline GM so the friction disc splines will fit. Your friction disc and pressure plate may need to be swapped to put up with your intended tow weight... but maybe not. Do your research.

The propshaft(s) is likely a different length.

The 2wd 4500 has a fixed output yoke vs the 3500 with a slip yoke.

The slip yoke propshaft probably has a larger size universal than the slip yoke. You can get hybrid universals to mate a propshaft to a different size fixed yoke or you can change the yoke to match a standard universal.

You're likely going to need to replace the master to slave line.

4wd output is 32 spline on both but the transmission lengths likely differ enough to cause problems with propshaft lengths.

[hb32]

Thanks for the detailed description hatzie. That rules out that avenue. On a similar theme, what would be a decent heavy duty clutch for a 3500 ? Looking at the Centerforce KCFT355216 which seems to be unavailable in Canada at least where I am located. Any thoughts on something comparable ?

[hatzie]

The 3500 has a torque limit of around 250-300ft-lbs. It may or may not put up with heavy towing and it doesn't have the lower 1st gear to get her going.

The other thing to think about is whether the 1/2 ton tires, brakes, and suspension are up to the task. On a lighter 1/2 ton you could easily end up with the trailer attempting to drive the truck instead of the correct way round. Both of my last 3/4 ton trucks came from guys that were moving up to 1 ton duallys to pull their big new 5th wheel campers.

As far as swaps like this go it's pretty straightforward. My guess is it's around a day or two of fiddling to get it to fit and since this as a GMT400 that already has a manual transmission it's maybe $100 in parts... $200 far on the outside and that's with the smaller Canadian dollars.

I'd get the propshaft(s) off the donor and use a hybrid universals on the diffs... if it's needed.
Moving the crossmember back is pretty easy.
I bet the 4500 shift tower is still under the 3500 hole in the floor. GM generally put a pretty big hole in the floor.