Upgrade to 5 speed manual

[kipps]

Originally Posted by cadillac_al

A guy wrote in to Four Wheeler magazine saying he put a nv4500 in a 70's K20 to replace a sm465 and it was an easy bolt in swap. He said it couldn't have been any easier. I made a mental note in case a sm465 truck finds it's way into my stable.

The sm465 to nv4500 swap does have a few unique challenges. The shift tower is about three inches rearward on the nv4500. This is beginning to intrude on the transfer case shift lever, but it can usually still be made to work. The passenger side slave is the worst problem with the 92-95 nv4500, when installed in a 4wd truck. For a 4wd, you really should go with an aftermarket bell, or a 96-07 nv4500 and bell.

But otherwise, the length is the same, the spline counts are the same, the slaves displace about the same amount of fluid, and the external dimensions are basically the same.

[44th Miss Inf]

Originally Posted by kipps

The passenger side slave is the worst problem with the 92-95 nv4500, when installed in a 4wd truck. For a 4wd, you really should go with an aftermarket bell, or a 96-07 nv4500 and bell.

I ran an early NV4500 with factory bell housing for over 10 years using the truck ie driving thru ditches, gullies, etc, never babying it and never had contact with the front driveshaft

Know of several others with them who abuse their trucks with no issues either. I think if the springs are worn out, or you put a big block in a truck with 2 leaf front springs instead of 3leaf (81-87 trucks) you may have a problem. But that’s worn out suspension not slave placement problems

[1976gmc20]

Originally Posted by cadillac_al

A guy wrote in to Four Wheeler magazine saying he put a nv4500 in a 70's K20 to replace a sm465 and it was an easy bolt in swap. He said it couldn't have been any easier. I made a mental note in case a sm465 truck finds it's way into my stable.

Oh! I would just love to find a K/20 in good condition with an SM465 and NP205.

The lack of overdrive doesn't bother me because I would only drive to town maybe a half dozen times a year.

[kipps]

Originally Posted by 44th Miss Inf

I ran an early NV4500 with factory bell housing for over 10 years using the truck ie driving thru ditches, gullies, etc, never babying it and never had contact with the front driveshaft

Know of several others with them who abuse their trucks with no issues either. I think if the springs are worn out, or you put a big block in a truck with 2 leaf front springs instead of 3leaf (81-87 trucks) you may have a problem. But that’s worn out suspension not slave placement problems

How much suspension lift is on those trucks? I mocked up a passenger-side slave on the truck in my signature, and decided I didn't want to take the chance.

[tucsonjwt]

I got a response to my email from Advance Adapters. The information they gave me is that it is not a simple swap. Here are the links they provided me:

Mechanical Clutch Linkage Adapter: $28.87

https://www.advanceadapters.com/prod...-bellhousings/

96 and up NV4500 bell housing adapter kit: $418.20

https://www.advanceadapters.com/prod...llhousing-kit/

Or 93-95 NV4500 Adapter kit: $438.48

https://www.advanceadapters.com/prod...llhousing-kit/

"Note: This bellhousing assembly can also be used with the SM465 4 speed transmissions."

The local transmission guy I talked to about this said the used NV4500 transmissions around here go for about $1,000 from a junkyard, but they might come with a 1 year warranty.

Looks like $500 is the typical core charge for transmission rebuilders, with $2K for an upgraded NV4500 plus shipping and tax, plus add about $500 for the adapter stuff. I am nut sure that my stock clutch will work, based on what I am reading.

I have heard and read that you can just replace the SM465 with an NV4500 and it is a simple bolt in operation but there is conflicting informaton.

Also, I would think I would need a new shifter and maybe a cutout modification of the transmission tunnel hole.

With a new driveshaft required I think this swap could easily be in the $4K range or more.

[kipps]

Originally Posted by tucsonjwt

I got a response to my email from Advance Adapters. The information they gave me is that it is not a simple swap. Here are the links they provided me...

They're assuming you will keep the mechanical clutch linkage. That's why they're pushing their adapter bellhousings, since that's the only way to use a mechanical linkage on a nv4500. I'd suggest the following method instead.

Go junkyard diving for a complete pedal setup from a manual trans 85-87 truck. These pedals are intended to work with a clutch master cylinder. Price will vary between $50 and $200 depending on whether it's a backwoods junkyard or if you get it from Ebay. This will include the brake and clutch pedals, the complete pedal "bucket" assembly that holds it all together, and the two braces that go to the firewall to support the clutch master cylinder.

Buy a new 85-87 master to use with the above setup. This master can be adapted to work with either a stock 92-95 nv4500 external slave or a 96-07 nv4500 internal slave. I have more info about the adapters needed if necessary, but they are relatively inexpensive. It should cost less than $100 to connect the 85-87 master to either of the nv4500 slaves.

Buy a complete 2wd nv4500, including the stock bellhousing. It will bolt up to any GM engine. The choice of flywheels and clutches will vary depending on what engine is involved.

Yes, there will be floor modifications needed. For a 2wd it won't be much of an issue, though. The shifter will come through the floor about three inches rearward of where the stock sm465 shifter is, assuming you're leaving the engine in the same location. It's all relatively flat metal, so it's easy enough to just pop-rivet a sheet of metal across the old shift opening, and slice open a new hole.

[tucsonjwt]

Thanks for the information Kipps.

For background, there are no square bodies left in the junkyards around here. A rust free square body in the desert Southwest goes for $2K and up, depending on how complete it is. The body can be dented up, but as long as the frame is rust free and straight they sell for top dollar. About 5 years ago people started snapping up the available square bodies off Craigslist and they never make it to the junkyards. Occasionally you will see one "lightly rolled" as they say in the junkyard business, but that is a frame only truck. Even the Suburbans are popular now.

I can see doing mods to get the NV4500 in place, but hacking the tunnel doesn't sound like my cup of tea. I am told by the transmission guy here that 2WD NV4500 are seldom seen, and he pays $1,000 when he finds one, so getting one of those would not be easy for me.

I will not be doing the work myself. I do the simple stuff, but R&R transmission and Gear Vendor is more than I want to tackle, especially with limited facilities and tools.

I do like my mechanical clutch, and don't want another hydraulic item to break.

Actually, the granny 4 speed is fine with me, but I do miss the Gear Vendor overdrive. With a 4:10 rear axle my engine is revving high above 35 mph in town, and that is where the GV was nice. When I had the GV working I could take my foot off the accelerator and the truck would coast to a stoplight easliy.
Now the truck feels like I downshifted into 3rd.

If I could fix the granny incontinence problem (leaking oil out the front) and fix the sloppy shifter without welding it up, then I would get a reman Gear Vendor and call it good. I am hesitant to buy a rebuilt SM465 online, since everyone I know who went that route got burnt. Transmission shops have the worst reputation for doing good work, and the big companies have the worst reputation. My granny shifts fine, so I am hesitant to give it up.