NV4500 Swap - Clutch/Hydraulics Dilemma

I've talked about doing this for a while, and am finally getting around to putting an overdrive transmission in my truck. I know there have been a number of NV4500 swaps done over the years, and I really didn't want to start a whole new thread about this, but I couldn't find my specific scenario described. So here is yet another NV4500 swap thread. After I make this post, I may come back and tag some of the folks who I know have done this swap. I know a couple guys are actually working their way through it right now. Anyway, let's get on with it...

Pertinent Background Info:
1990 GMC 2500 Suburban
454 / SM465 / NP205
Hydraulic pedal assembly, bellhousing, clutch kit, master cylinder, external slave cylinder and clutch fork (driver's side of bellhousing) from 1985 K30

I picked up a low(ish) mileage NV4500 that was pulled from a 2001 Silverado 2500HD. I have the original bellhousing, clutch kit and internal slave cylinder/release bearing assembly that came from that truck. *Note: the slave cylinder opening is also on the driver's side of the bellhousing.* I do not have the master cylinder or pedal assembly from that truck. I figured I'd be able to use my existing pedal assembly and clutch master cylinder.

While setting all my parts out this weekend I realized that the hydraulic hose for the internal slave cylinder has a large fitting that looks to be some sort of quick-connect style connection that goes to the master cylinder. This does not appear to be compatible with my existing clutch master cylinder. So I started looking into getting a master cylinder from a 2001 2500HD. Well the pushrod connection to the clutch pedal is different than my existing pushrod and pedal connection.

So, my initial questions are as follows (depending on the responses, I will likely have follow-up questions):

1. Is there an easy way to adapt a 1996+ style NV4500 internal slave cylinder to my existing SM465 master cylinder?
2. Is the SM465 master cylinder going to move the volume of fluid needed for the NV4500 slave cylinder?
3. Is my existing SM465 clutch kit (disc and pressure plate) and pilot bearing going to work with the 2001 NV4500 input and slave cylinder/release bearing?

I know there are options for retrofit external slave cylinders, different bellhousing options, etc. I would like to use as many of the parts that I already have, and minimize the amount of money I have to spend on retrofit components. I would also prefer to use my existing clutch kit, as it is a relatively new Ram Clutch kit, versus going with the clutch kit from the donor Silverado.

Lastly, no, I have not pulled the SM465 out yet, so I'm not able to set the transmissions or clutches next to each other and compare. I can get some pictures of the NV4500 components if that helps. But I know there is a wealth of knowledge floating around on this site. So hopefully someone can point me in the right direction.

 

And a picture just because...

 

6 in one half dozen the other...

This is all based on my research and I am in no way an expert. But...my setup does work and I slept at a motel 6 last night.

If you’d like to use your newish sm465 clutch, etc. you need to get the advance adapter bellhousing. It’ll let you use the sm465 stuff, including your existing master, hose and slave.

If you want to use the internal slave bellhousing, you’ll need to experiment with clutch and flywheel packages although a package for a 98ish 3500 with a small block should be close... Not 100% sure on the hydro line for this setup, although there may be a adapter hose. If not, a good hydraulic shop can make you anything. That is, of course if the fluid volume displacement is the same on the internal slave master and your master.

If you ask me, $450 for the AA B/H and slave bracket gets you using all your other stock stuff. That’s not too bad. My clutch kit and flywheel was damn near that much alone.

 

As much as you don't want to, forget the factory stuff and buy the AA bell housing. I had the factory bell housing and a brand new 12" clutch that came from the donor vehicle. It's too much of a hassle trying to make it all work together. The clutch didn't fit in the bell housing anyway. Buy the AA housing and a standard 11" clutch.

I would forget the internal slave/TO bearing. You will need a different input shaft bearing retainer to accommodate the early external slave setup.

The swap is not for the faint of heart especially if your converting from an auto!

 

Best I can tell, they were put in GM trucks up to 2007. But I'm no expert on the history of the NV4500. I just knew that I wanted a 96 and up version.

 

I'm glad you guys chimed in! I knew you both were working on this recently. As much as it pains me to say it, you're both probably right about the AA bellhousing. I tried to avoid going that route for the simple fact that I think AA is WAY too proud of their stuff. It definitely seems like the easy button though, and I'm not necessarily opposed to that.

I seem to remember reading something in the past about people using their SM465 bellhousing, and machining it to accept the NV4500 front bearing retainer. I can't remember if new mounting holes had to be drilled in the bellhousing also. Can anyone shed some light on the potential for going this route? If it's doable, it seems like I'd be able to retain most/all of my clutch and hydraulic components.

 

That's possible. I believe the front bearing retainer needs machined and the mounting hole spacing on the trans end needs drilled & tapped. This is not something you would do yourself but requires precision machining to keep everything centered or you'll be replacing bearings and shafts in short order. For me, it came down to economics. Machine shop time is expensive.

Get the AA conversion "kit" and it starts making more sense financially. You're going to put a lot of time and effort into this, you don't want to get it all together and have to pull it back apart because of a faulty used part.

Granted, mine was converted from an auto and pulling the dash apart to swap the pedal assembly was a major PITA. However, when the moment came to crank it over the first time, I was ecstatic that if fired up with no noise, vibration or other issues. The first time I got on the highway and dropped it into overdrive I almost pissed myself with joy!

 

You are correct. Moreover, guys that had trucks with the ZF 6speed preferred the NV 4500 almost every time. 4500's shift like butter!

 

Ahh, so you would drill/tap the front of the transmission to match the existing holes in the SM465 bellhousing in lieu of the other way around...yeah, I don't want to do that.

Just to make sure, this is the bellhousing kit I think I need 712576 : Chevy V8 & V6 to the 1996 & up GM version NV4500 5 speed, adapter bellhousing kit. | Advance Adapters

Will my existing external slave bolt to the side of the AA bellhousing? Or do I also need 715535 : GM Hydraulic Clutch Linkage Bracket for use with Advance Adapters NV4500 Bellhousings | Advance Adapters

Will my existing throw-out bearing work with these AA parts? These are probably great questions for AA, but I seem to get quicker answers here.

 

Those are the correct PNs. The b/h is designed to be used with the sm465 clutch components and flywheel, so you should be good to go.

 

I got all new EXEDY brand components (master and slave cylinders and hose) from Rock Auto for under $100. Ordered for an 85 model year. Cheap insurance.

The TO bearing will depend on your specific clutch. My 12" clutch hit the inside of the BH, my new McLeod does not.

 

Awesome. I will give them a call just to see if there is anything else they need to sell me. Then I'll probably search around for the best price on those kits. Summit has traditionally done me right on price, free shipping, and because they have a warehouse in ATL, I usually get my order next day.

I am 95% sure I replaced my slave and master cylinder with parts store components when I did my new clutch probably around 5,000 miles ago. Doesn't mean they won't give out tomorrow, but those parts are easy to replace even after the swap is all done. I'll probably hold of on that for now.

 

I did the swap about 10 years ago. I started out with a 79 k20 GMC with a new GM crate engine and a turbo350 without a lock up convertor. AA bell housing, external hydro clutch, with an after market clutch pedal that was tricky to line up the linkage. It also had a remote under the hood hydro reservoir. NP205 transfer case with AA clocking ring. Gas mileage went from 8 to 15mpg.
I think automatic trucks might have higher rear ends than manuals. I do not know for sure but it does not have the power to pull 5th gear without sucking more gas than 4th gear. 3rd gear on the NV4500 feels like 3rd gear with the old turbo 350. The truck sees no highway use so if I had to do it again I would have installed a SM465 / NP205. The gear spread would have been better than the NV4500 for what the truck is used for. The truck was originally AWD all the time spinning the front axle. I am sure getting rid of that problem saved me some MPGs. (AWD was more fun to drive and seemed to turn shorter.) The NV4500 is a nice shifting transmission once the oil warms up. However it is still shifts like a truck and not like a car. Advance Adaptors are great for support.

 

I hear ya. If this was a farm/woods/trail truck, I would definitely leave the stout SM465/NP205 combo in it. I would actually really like to keep the 205 in it with the new transmission. But another $600 for an adapter is not in the cards. I got a low mileage, good condition NP241c for a good price, so that's what's going back in it. If we weren't on opposite sides of the country, we could have traded setups, lol.

My goal is to get this truck back into more regular towing duty. With 35" tires, 3.73 gears, and no overdrive, it doesn't pull nearly as well as it needs to. As part of this upcoming transmission swap, I'll also be throwing a deeper set of gears in it. I'm leaning towards 4.56 gears right now. With overdrive, I believe that would reduce my highway cruising RPMs slightly, but more importantly, give me the grunt I need to pull.