gm nv4500

[south456]

hey guys i have been considering putting a 90s nv4500 in my 1985 square so it will have overdrive and i can actually drive it on the freeway, has anyone done this and can shed some light on how difficult it is actually going to be. i know i will have to get a adapter to put my np205 on the back of it and i know the frogger arm is on the passenger side not the drivers but what else will there be?

 

[SquareRoot]

First things first. What trans and t-case do you currently have? I know someone who is familiar with this swap.

 

[south456]

I currently have a sm465 tranny and np205 transfer case

 

[SquareRoot]

Is the truck currently using the 465? Just clarifying if the truck originally had a manual or auto. Since K20's didn't come with a 205 in 85 I'll assume it's not original either. Is the 205 the figure 8 or round pattern version? There's a reason I'm asking these questions, hang with me.

 

[85K304SPD]

Following... My '85 K30 has 465/205. Overdrive would be awesome!!

 

[south456]

Is the truck currently using the 465? Just clarifying if the truck originally had a manual or auto. Since K20's didn't come with a 205 in 85 I'll assume it's not original either. Is the 205 the figure 8 or round pattern version? There's a reason I'm asking these questions, hang with me.

The truck currently has a 465 it was stock manual and i swapped in a 205

 

[SquareRoot]

Good news is your 90% there. You need the correct bell housing. You can modify yours or buy the Advance Adapter one. Your existing member will work. Mine bolted into the same holes on the frame. You need a 4500 specific trans mount. You will need a shifter and bracket of some sort to work the t case. Now's a perfect time to swap it to a twin shift setup. ORD and others have shifters and brackets specifically for this application. Also, put a fixed yoke on the output shaft and get the shaft adjusted if needed. It will need a slip joint put in it regardless. I love my setup. It's worth the effort.

 

[south456]

Good news is your 90% there. You need the correct bell housing. You can modify yours or buy the Advance Adapter one. Your existing member will work. Mine bolted into the same holes on the frame. You need a 4500 specific trans mount. You will need a shifter and bracket of some sort to work the t case. Now's a perfect time to swap it to a twin shift setup. ORD and others have shifters and brackets specifically for this application. Also, put a fixed yoke on the output shaft and get the shaft adjusted if needed. It will need a slip joint put in it regardless. I love my setup. It's worth the effort.

Cool! Thank you for your help.

 

[Jester67]

I don't want to hijack this, but would it be the same if you had a 208 Tcase?

 

[7900_Blazer]

I've done this swap 3 times... I just finished this for my 1975 GMC Jimmy; and back in the spring I did this swap in my 1985 K20. As @SquareRoot said - you'll need a bellhousing - I ordered my from Advanced Adaptors.

My Jimmy had the np203 transfer case which will not mount to the back of the NV4500 without an adaptor but I wanted 2wd anyway so I sourced an np208 transfer case from a salvage yard. I don't think the NP205 will mount to the NV4500 without mods but I can't speak from experience on the np205. The np208 bolts right up no problem. Note to self: make sure if you go the NP208 route - that you find one that matches the drop side of your front differential.

I had to have both drive shafts modified. For the rear I used Tom Woods Driveshafts (cheaper than my local shop and as fast even with shipping it from Utah) simply because the rear of the np208 takes a slip yoke... and I also needed a CV-joint there - only Tom Woods seems to have that combination for the NP208.

For the '75 Jimmy, I had to source a 'W' style cross member for the NP208 - salvage or ebay, or if necessary there is a company that builds them called Tejas Steelworks, Inc. - my '85 already had the 'W' style cross member.

Lastly I had to build some clutch linkage as the pushrod for my SM465 was to short for the NV4500. I picked up some threaded rod from Tractor Supply and built my own.

Overall a really simple swap - I can now cruise at 70 mph at 2000 rpm.