Re: NV4500 swap is underway
 

I swapped to th400 in mine and it came with the brace arm that you show Larry. I've been contemplating how to mount it with the torque mount. Reading your comment's make me think to just take plate off. Then mount bar. Would make more sense. I really don't want to break tranny case. Thanks, Daren

Re: NV4500 swap is underway
 

The support rod from the tcase to the trans bell is a good idea and I will eventually do that too once I find a support rod to modify to fit my contraption. The bracket from the tcase to the frame is a horrible design which has been a topic of many threads here in the 4x4 section and it seems everybody has and opinion.

Members Zoomand75, BeamN7, and I work in the class 5 through 8 truck manufacturing industry where one of our retired colleagues is also a retired service engineer from GM. In his years of service at GM he worked with GMC Truck and Bus after graduating GMI sometime in the 1960’s. Back in 2010 when I was doing this NV4500 swap the topic of supporting the tcase kept coming up over and over which I asked Winston his thoughts. Winston is an old guy with an engineering degree that can make any short story long where he told me all about the tcase adapter issues on 1969-1972 Chevrolet and GMC trucks that used the 205 to frame brackets and did not allow the tcase to rotate with the rolling torque of the engine resulting in broken adapters. He told the story like it was yesterday then said DO NOT use a frame to tcase mount and if you have an old truck with the bracket remove it. Much of his experience was supporting the Trans-Alaska Pipeline construction contractors where GM trucks were used to their fullest. The duty cycles those trucks saw on the job may not appear in a personal use truck for decades.

Yes, there have been tons of stories where members here claim to have a 43 year old truck with the tcase frame bracket and never broke a single adapter or broken bellhousing on a TH350 that they know of. Great for them, but the propensity of an adapter or auto trans bellhousing failure is much greater with the frame bracket. As he mentioned, tcase adapter failures on manual trans trucks happened often anyway even after the frame bracket is removed. That is one of the reasons GM was so happy to move to the SAE 6 bolt round adapter in 1985. The old skinny adapter used on the figure 8 205 tcase is just the weak link in the driveline but the tcase to frame bracket makes it far worse.

Back to the support/torque rod, the reason it is a good design is it supports the cantilevered weight of front output side of the tcase but the entire assembly is still supported to follow the engine/transmission assembly torque roll. This is the reason GM ditched the frame bracket in favor of a torque rod after 1972 although not all trucks got a torque rod. Which got them and which didn’t is still a mystery.

Funny modern story somewhat related to this concept. Our company used a long oil fill tube that was attached from the valve cover to the radiator support which is bolted to the frame at the other end. With the torque rotation of the engine, the oil fill tube adapter in the valve cover broke on thousands of our trucks because the entire assembly was not rotating together which allowed it to pull itself apart as the powertrain moved around during normal operation. That is exactly what happens when you tie the tcase to the frame and not allow it to rotate with the torque roll of the engine/trans assembly.

Re: NV4500 swap is underway
 

I'm befuddled by the direction this thread took on the mere outside chance Larry might break the rear housing on his 4500. I know there are other guys running 4500's on this board and others like CK5 and don't remember them getting spammed with posts needing the cast iron rear housing.

Having been at this dealer for the last 5 years we've replaced 1 NV4500 in a 2002 Silverado 2500. Was the rear housing broke? Nope. It was popping out of 5th under load. I can say this having wheeled with Larry, he's no throttle jockey. The chances of his breaking is no greater than one that was installed in a truck from the factory. When you have torque on demand like his 8.1L builds you don't have to beat on it like a rented mule to accomplish the task at hand. Now that he's pulled the advance adapter's chunk of beef off of the rear of the trans and gone to a factory round 205 for a direct bolt on, his chances of stuff breaking should have gone down, not up.

Re: NV4500 swap is underway
 

i wheel a k5 blazer with a 396 nv4500 203 205 with one tons and 42 inch tires. i am not at all worried about breaking my adapter.

Re: NV4500 swap is underway
 

hey Larry hows it goin, can a chevy 2wd 32 spline shaft tranz have the rear shaft whacked off like this and a 4wd rear housing bolted on then a 88-91 241 bolted up to it--and instantly made into a 4wd---for a DSDrop setup?
and whats the big deal with having to cough up the $$s on AA bells---as far as a early 93-5 chevy version,, any old bell could just be taken to a competent machine shop and have the bearing opening opend up to 5 1/8" --someone could use a cast iron bell too ( easier to weld on--redrill /modify) and the same ole throwout lever.

Re: NV4500 swap is underway
 

As far as I know you can cut a 2wd NV4500 for use with the AA kit to use a 205 but, you would probably be money ahead by just replacing the 2wd mainshaft and rear cover with a 4wd mainshaft and rear cover and just use a 32 spine 205, 208 or 241.

The big deal with using the Advance Adapters bell is the fact that setup allows you to run all stock GM hydraulics from an 85-87 (up 91 in square K5’s, Suburbans). By using the AA bell you can use off the shelf square body specific master cylinder, slave and most importantly the hose. You can certainly use a 92-95 bell but the slave is on the wrong side where a custom hydro hose would need to be built. Building a hose isn’t a big issue but it is when you are in the middle of friggen nowhere like where I go with my truck. Having all mostly stock / off the shelf parts sure makes life easier if you do have a roadside break down and need parts fast.

There are a few ways someone could go about making various bells work, just go the route that fits your need and priority.

Re: NV4500 swap is underway
 

OK thanks for the input, i like the idea of the good old TOB arm, --no hydraulic stuff to piss on the clutch and needing to take the whole damn truck apart to replace. And I also dig the idea of clutch CABLE actuated, but thats a custom mod project having to use parts from--say a mustang, etc.
Do you know if all the newer type nv4500's without the snout sleeve can easily have an earlier type front shaft retainer with the sleeve for a conventional TOB just bolted on and replacing the hydraulic style retainer?

Re: NV4500 swap is underway
 

I’m just the opposite. I don’t miss the old z-bar mechanical clutch linkage at all. It gets old when the linkage gets all bound up to the point the rod falls off or shears off the pivot ball when the truck is flexed out. You don’t have that problem with a hydraulic clutch plus they are much nicer to step on. Very soft. A cable clutch would be a bad idea just like it was in a lot of cars of the 80’s.

I don’t know for sure if the front bearing retainer would transfer from an older NV4500 to a later one but I don’t see why not. If you research the Advance Adapters bell that you commented on you will find it also comes with a front bearing retainer for use with a standard release bearing. Their bell kit allows for use of a mechanical z-bar clutch linkage or like I mentioned before, a slave from an 85-91 square body…..so no fluid leaks on the clutch like the 1996 and later model trucks are famous for.

You can see the front bearing retainer for a standard release bearing on the NV4500 on the left
https://farm9.staticflickr.com/8355/...22269ac8_c.jpg

Re: NV4500 swap is underway
 

Larry, do you have any idea what the AA shift handles originally were for? My brother just purchased a brand new NV4500 and it came with the same goof ball handle. :lol:

Re: NV4500 swap is underway
 

Their handle looks homegrown but their knob looks like a late 80’s Jeep knob to me.

Re: NV4500 swap is underway
 

I am in the same boat i have a nv4500 with the 2wd 32 spline shaft and want to go with the 205 t case too .Might cut the out put shaft and get a tail housing that bolts up or run one divorced.I am taking a lake wood blow proof opening the center up to 5 and an eighth .Then drilling it to bolt to the trans .Then i can run a mechanical clutch linkage or a external slave and master cyl .And have a blow proof housing .After 50 years i find im kind of attached to my nuts.ha ha

Re: NV4500 swap is underway
 

Where did he purchase it from? I thought that these have been out of production for a while now and everything available was rebuilds?

Re: NV4500 swap is underway
 

Larry,
How has the modified, aluminum adapter housing from the NV4500 to NP205 been holding up? I'm getting ready to do my swap in the next month or so and was hoping to get your feedback. Let me know what your observations have been. Thanks!

Re: NV4500 swap is underway
 

Still not sure why people are nervous about the aluminum adapter but yeah, it’s working fine. In May we ran a couple thousand miles around Arizona and Utah. 200 miles in Canyonlands bouncing and crawling for 2 days in 4 low. The front shaft tried to commit suicide and pulled the front yoke on the 205 loose and still didn’t cause any issues with the aluminum bracket. The twin stick 205 is still giving me fits though. That beoatch does not want to SHIFT wants it hot on the trail :banghead:

Re: NV4500 swap is underway
 

Good to hear. It never hurts to check!

Re: NV4500 swap is underway
 

i have the AA spacer and case hanging off the OEM AL housing in my M715. for the last 5+ years. no issues what so ever. has at least 20K on that rig since built. pulled the trans and tcase for a clutch issue and re-checked everything while it was on the ground and the studs/nuts are tight and right still.

Re: NV4500 swap is underway
 

I rock crawl my nv4500 with a doubler on the end.

Re: NV4500 swap is underway
 

Hey larry nice set up im starting on my nv4500 swap im still trying to gather up all parts I got trans aa adapter 10 spline 205 31 spline output What do you recomend should I run it like that or upgrade to 27 spline also I got 93-95 oem bell im mounting behind my 5.3 is that going to be an issue the only thing I need is the pedal assembly you where I can find one.

Re: NV4500 swap is underway
 

There's a guy on the Pirate site that has a stock of new OEM late model NP205 cases. Bought mine for $80. AA has an adapter (basically a 2" solid spacer) that sells for around $60-$70 (I think?). This is the way I went to get the strongest and shortest (and newest) NV4500/NP205 setup. I also got a brand new 32 spline and bearings from him. He owned a company that converted/upgraded new trucks to HD specs for the forest service and emergency vehicle applications (ambulances, etc.)

Re: NV4500 swap is underway
 

Thanks for that info but my nv4500 has that big 31 spline output shaft that can only be used with a coupler think

Re: NV4500 swap is underway
 

It's possible to use the early TH400 32 spline input for the 205 and not use the 2" spacer to get 2" shorter, if shortest is the goal. I've actually got the long input and spacer like sunsoaked but debating whether to convert...

I searched and just looked on pirates classifieds. but didn't find any clues about the person w/ the round pattern cases. Got any more info?

Thanks!

Re: NV4500 swap is underway
 

31 spline is Ford and I don't think the 4500 used 31 splines... GM: 27/32 and Dodge 23/29 splines...
GM switched the bolt pattern early on to the Dodge style so if you have a Dodge trans or an early GM BH, they may not match.
Advance Adapters has a conversion guide you can download or ask them to send it to you w/ lots of info.

Re: NV4500 swap is underway
 

I have a nv4500 mated to a fig 8 np205 dont know what year the trans is but it has AA to mate the 205 it has a fat coupler 31 splines and 10 spline for the 205. I think they change the output on the trans because I never seen a output that big I thought 32 spline was the biggest. I bouht the the set up off a guy that had it rebuilt and never used it i payed 1300 for the whole set up nv4500 complete with adapter and 205 but when I got home I seperated it and thats what I found 31 spline mated to 10 spline np205 so is it a dodge or chevy trans because it has a chevy bellhousing as well im confused here

Re: NV4500 swap is underway
 

Welcome to the 67-72 forums Alberto! Sounds like you have a 10 spline 205 that was originally behind a 465 manual trans. It also sounds like the NV4500 you have has already had the mainshaft cut for the AA kit (that is where the 31 spline comes in). If that is indeed what you have the 31 spline to 10 spline sleeve from AA will work. The only issue is most 10 spline 205 have pretty ugly splines where even with a new sleeve they can be pretty sloppy. That is why I went with a 27 spline when I first did this NV4500 swap a few years ago plus the fact I could not find (or willing to pay for) the ideal round pattern 32 spline 205.

The 93 bell with the passenger’s side slave can become an issue depending what you install this setup in as you must build your own hydraulic line or use a 88-94 master cylinder, which does not work well in a 73-87 truck. If you’re looking for square body truck hydro pedals good luck. They are getting harder and harder to find every day.


Funny, there is always this “guy” or “some website” that sells these elusive new round pattern 205 cases. Steve talked about those years ago and when I was ready to buy nobody could come up with the source that sold them. :lol:

Yep, exactly. I agree. That is what I did on my NV4500 version 2. I used the TH400 short input so that way I wouldn’t need that AA spacer. See post 284 of this thread.

The NV4500 does have 31 splines when you cut the mainshaft and use the AA sleeve. If I remember correctly, the 31 spline is where I believe the damper would go if the trans was equipped with one. This is when we cut the mainshaft for provisions of the AA sleve.
https://farm5.staticflickr.com/4103/...0e702523_z.jpg

Re: NV4500 swap is underway
 

If you read through all 14 pages of this exact thread it should shed some light on what you have. It sounds to me like you have pretty much the same AA kit that I originally started with other than you have the 31 spline to 10 spline sleeve whereas I had the 31 to 27 spline sleeve.