Switching my sm465 to a nv4500 in a 1969 Chevy C20

[raycow]

Your question is a good one. My personal feeling is that the cast iron bellhousing is way overdesigned for the job it has to do. We have a member on one of the boards here who is planning to hang a Gear Vendors overdrive off the back of his stock 4 speed without any additional support.

If you intend to use the truck primarily on pavement, I can't see how you would have any problems with the stock mounting setup. If you will be driving on badly rutted roads or off-road, then maybe you might want an additional crossmember under the rear of the NV4500 just for insurance.

Ray

[treveiger]

Im the type where id rather over do it. Could i take the crossmember out of a chevy truck or a dodge truck with a nv4500 and use that?
Thanks

[JJorgensen52]

The cast iron bell housing is the same all the way through 60 series big blocks, so I wouldn't expect you to have ANY problems with that.

I'm about halfway through my swap (unfortunately got called for duty and won't be back home until mid-October) - I've taken a lot of pictures but can't upload them from here.

So far, I've learned the following:

SM465/T221 trucks have two cross members, one under the trans/tcase adapter and one under the front yoke of the driveshaft with a skidplate. On my truck, there were two sets of mounting holes, and the stock position was the forward set. I was able to unbolt my cross members, move them back one spot and reinstall them in the factory holes with the NV4500/NP241 in place.

I had to modify the transmission crossmember on the passenger's side to clear the NP241 output (it's roughly 2" lower than the T221's is). I was able to weld the '94 truck's transmission mount adapter onto my original crossmember without any cutting or bending and have it line up at the appropriate height and position.

Both driveshafts need to be modified. My original rear shaft was about 52" length, my new one is 36.5". I used a new slip yoke and pinion yoke on the rear end with 1350 u-joints. I have not done the front shaft yet, but it's going to have to be longer than factory and I am most likely going to stick with the factory 1310 joints for that (with a double cardan joint at the case).

The shifter location is about 5 3/8" back from the SM465 shifter. With the AA bellhousing, I was able to reinstall and have correct clutch operation without even changing the adjustment on my clutch linkage. I did change to the starter I mentioned previously, and needed one shim on the outboard side to obtain correct engagement. Shows me for saying I've never had to shim

The present hangup I am having is a dragging clutch. This is my own fault, I installed the clutch disc into the pressure plate reversed, so it's dragging against the flywheel even when disengaged.

I did all the work myself in the span of about 3 full days. I'd estimate I have two days left to get everything back together and done (including repulling everything to fix the clutch).

I still need to make a shifter linkage for the transfer case, but I've already got it designed so it's going to be a quick project.

I have a two pictures that I took with my phone of the trans/tcase and the modified crossmember - when I finally get home I'll have lots more to upload.

This was after final test fitting - I welded reinforcements in at the joints where the old crossmember ends on both sides. The material was all 3/16" mild steel in the crossmember, so I used 3/16" angle and plate to make the new section.

[JJorgensen52]

Originally Posted by treveiger

Im the type where id rather over do it. Could i take the crossmember out of a chevy truck or a dodge truck with a nv4500 and use that?
Thanks

The newer truck's cross members are too wide. You'd be better off finding an original 4wd truck crossmember and bolting it in - as I said in my post, the height and positioning on the frame are very close. If you drilled new holes, all you'd need to do would be bolt on a spacer - maybe 1/2" or 5/8" - and drill holes for the tranny mount to bolt through.

[treveiger]

JJorgensen52 is your truck a 4x4? So i shouldnt need another crossmember to help support the nv4500?

[JJorgensen52]

Originally Posted by treveiger

JJorgensen52 is your truck a 4x4? So i shouldnt need another crossmember to help support the nv4500?

Correct, my truck is a 4x4.

The actual mass of the NV4500 (while slightly heavier than an SM465) is in about the same location (since the tail housing is aluminum). There were other transmissions in the 40-50-60 series trucks that were MUCH heavier than an SM465.

That said, I see no problems whatsoever with a stock crossmember/bellhousing and an NV4500. If I were swapping a 2wd truck myself, I would put in a crossmember because:
A. I don't like the idea of the transmission hanging that far behind the mount, knowing I use my truck for work, hauling and plowing
B. The frames in our trucks might as well be made out of play-doh, they need all the help they can get!

Here's my philosophy on all vehicle parts swapping: If the General did it, and it isn't a known problem causer, then it's good enough for me. I like to use as many OEM parts and pieces as I can when doing these kinds of things, because they are usually the most proven combos you can put together without breaking the bank. So, I'd go right ahead and leave your crossmember as is.


Now, I knew you were doing a 2wd swap when I suggested the 4x4 crossmember. The reason I suggested that one, if you wanted to add a crossmember, is because it is the correct dimensions to bolt into your frame, and it is at almost exactly the right height to mount the NV4500 without modifications, making it the easiest way to add a crossmember

[treveiger]

So i should try and grab a crossmember from a 67-72 chevy 4x4? Would that directly bolt up to the NV4500 without any mods? Im not planning on using my truck forwork to much but i do have trailers, boats, and a camper i can and probably in time pull with my truck and want to make sure its as strong as possible. I have thought about also the front and rear sway bars for my truck and maybe an anything else i can think of to make my frame and control as solid as possible lol.
Thanks

[JJorgensen52]

Originally Posted by treveiger

So i should try and grab a crossmember from a 67-72 chevy 4x4? Would that directly bolt up to the NV4500 without any mods? Im not planning on using my truck forwork to much but i do have trailers, boats, and a camper i can and probably in time pull with my truck and want to make sure its as strong as possible. I have thought about also the front and rear sway bars for my truck and maybe an anything else i can think of to make my frame and control as solid as possible lol.
Thanks

Correct, it will bolt in without modifications. You'll most likely have to use a spacer (I think it would be about 5/8", but it could be thicker or thinner depending on the angle your stock crossmember holds the bellhousing at) to mate up with the tranny, but that's a simple thing to do.

[Jacfourteen]

suscribed!

[treveiger]

What about a crossmember out of a 71 cheyenne 2wd automatic? Do you have any pictures of a 4x4 crossmember so i know what im exactly looking for?
Thanks

[treveiger]

What about the drive shaft, what kind of modifications would that need if i went with a dodge nv4500, i know i need to shorten it but was thinking about going with one piece anyway. The year i think i need is a 93-97 gas dodge truck, is that correct or is there a eaiser year? Any information would be great.
Thanks

[JJorgensen52]

Originally Posted by treveiger

What about a crossmember out of a 71 cheyenne 2wd automatic? Do you have any pictures of a 4x4 crossmember so i know what im exactly looking for?
Thanks

A 2wd crossmember would also work; my preference would be the 4wd crossmember simply because it bolts to both the top and bottom of the frame rails, making it a better reinforcement.

The pictures I posted of my modified crossmember are of a stock 4x4 member, I modified only one side of it and added the platform mount in the center. Haven't got any pre-mod pictures I can upload right now

Originally Posted by treveiger

What about the drive shaft, what kind of modifications would that need if i went with a dodge nv4500, i know i need to shorten it but was thinking about going with one piece anyway. The year i think i need is a 93-97 gas dodge truck, is that correct or is there a eaiser year? Any information would be great.
Thanks

It's impossible to say for sure what length you're going to need, but you will need it shortened as both Dodge and GM units are considerably longer than the old SM465 was.

Your info about the dodge is correct; you don't want diesel because of the oversized input shaft.

Whichever box you chose, you're going to need a driveshaft yoke that matches the transmission (be it a slip yoke or fixed). I had a new driveshaft made for my truck, including a new slip-yoke for the transmission and a new rear-end pinion yoke as well, for about $360. If you have a serviceable tranny yoke and keep your stock pinion yoke, make that $150.

My driveshaft (factory) was 54 1/2", my new one is 36 1/2". I've heard you can safely run a one piece driveshaft up to 72", but I don't think I've ever seen a factory one past about 58". I would check with a local drivetrain shop on that count.

[treveiger]

JJorgensen52 Thank you , i keep coming up with more questions lately as i do more research. So my local drivetrain shop would be able to tell me what i all exactly need? Why did you decide to go with a GMC NV4500 other than a NV4500 from a dodge?
Thanks

[JJorgensen52]

Originally Posted by treveiger

JJorgensen52 Thank you , i keep coming up with more questions lately as i do more research. So my local drivetrain shop would be able to tell me what i all exactly need? Why did you decide to go with a GMC NV4500 other than a NV4500 from a dodge?
Thanks

Having the questions now is better than halfway through the swap - I know that one from experience - I spent a good 10 months doing research into this swap before I made one single phone call looking for parts.

Yep, a drivetrain place should be able to help you match up all the yokes, seals and driveshaft parts once you decide what tranny to use.

I am using a GM NV4500 primarily because I wanted to get the lower ratios that dodge never offered. I loved my SM465, just the lack of an overdrive was killing me as I've been doing more highway driving lately - so I chose the 6.34 GM box to be as close to original as possible.

It also made my swap (read 4x4) a bit easier because of the transfer case I decided to use.

[treveiger]

Ya im like that to i have to be able to know exactly what im doing or at least know as much as i can.

I love my sm465 to but you can tell its starting to get wore out pretty good, its leaking and has some decent play in it so either i rebuild it or get the nv4500 with overdrive and still have a good transmission.

Thanks, im sure ill have more questions later.

[Junkpyl]

Hey fella's, any new info on the swap? Has anyone finished one in a 2wd and what was the final outcome. I want to do this to my C-30. My poor little SM465 is getting pretty sloppy. Great thread btw. Based on the info here, it looks like the adapter plate and Dodge version is the way to go. Does anyone know what year range is the most desireable? What year did the mechanical speedo go away? Thanks for any more info.

[treveiger]

Originally Posted by Junkpyl

Hey fella's, any new info on the swap? Has anyone finished one in a 2wd and what was the final outcome. I want to do this to my C-30. My poor little SM465 is getting pretty sloppy. Great thread btw. Based on the info here, it looks like the adapter plate and Dodge version is the way to go. Does anyone know what year range is the most desireable? What year did the mechanical speedo go away? Thanks for any more info.

I have the info at my house, i was going to do the dodge swap but decided i like my 465 to much and am going to rebuild it. Ill look at it tonight and see what year was needed for the best and easiest swap.

[LockDoc]

-
While you are waiting you can type in NV4500 into the google search box at the top of this page, click on the circle in front of 67-72chevytrucks.com, and click on the Google button. You will have to sort out 2w vs. 4x4 but there is a lot of info.

LockDoc

[treveiger]

I did a little research on it to make sure i got it right and these were the best sites i used to compare the 465 to the 4500

http://en.wikipedia.org/wiki/New_Ven...0_transmission

http://www.novak-adapt.com/knowledge/sm465.htm

From what i understand the easiest swap is the 1993-1997(that way you still get the Gear drive speedometer in tailhousing)after 97 there is no speedometer gear instead they have the VSS in axle.

Make sure you get the standard duty instead of the heavy duty one because the swap is harder, those two websites will help on any info or questions you have and of course if you have anymore questions this site and thread is great to

If anybody has anymore info please feel free to chime in!!!

[Junkpyl]

Thanks for the info. I appreciate it.

[treveiger]

No problem, have anymore just ask

[truckeez]

Originally Posted by JJorgensen52

Having the questions now is better than halfway through the swap - I know that one from experience - I spent a good 10 months doing research into this swap before I made one single phone call looking for parts.

Yep, a drivetrain place should be able to help you match up all the yokes, seals and driveshaft parts once you decide what tranny to use.

I am using a GM NV4500 primarily because I wanted to get the lower ratios that dodge never offered. I loved my SM465, just the lack of an overdrive was killing me as I've been doing more highway driving lately - so I chose the 6.34 GM box to be as close to original as possible.

It also made my swap (read 4x4) a bit easier because of the transfer case I decided to use.

I got a question--a few posts above yall are talking about the cast iron bell, Im wanting to use a nv4500 to a 292 truck six--and those got the 3 bolt starter that bolts to the bell--instead of the block , anybody know how this is done or what yrs nv4500 could work? Thanks

[truckeez]

Originally Posted by truckeez

I got a question--a few posts above yall are talking about the cast iron bell, Im wanting to use a nv4500 to a 292 truck six--and those got the 3 bolt starter that bolts to the bell--instead of the block , anybody know how this is done or what yrs nv4500 could work? Thanks

I lucked out -my free rebuilt 292 is drilled for the sbc style starter too!

[Inline Fury]

As far as bolting a nv4500 to an inline six goes, the stock flywheel, clutch and pressure plate will work. My 292 only has 2 bolt holes for the starter, so i ordered a chepo racing starter that has 4 holes inline for either flywheel size. It worked great.