Finally caught a break NP440 / MY 6

[Brad54]

Thanks for the kind words guys!
I'm really glad you got some benefit out of that article.

I honestly don't know the power handling capacity of these transmissions--I bought it used, had it rebuilt, and dropped it in front of my 290hp crate engine and beat on it for several years... 60,000 miles and it's still operating perfectly.

That said, I don't know WHY I'm still hunting for an iron case version, but I am.
Maybe to put in my '56 Chevy with the hot rod 283 I've got planned for it.

As for the OD ratios: Depending on the application, the OD ratios for a T5 are .86 to .73... and the .73 ratio versions are 4-cylinder mini vans. I believe most performance applications are .86:2 final.

-Brad

[Rich 5150 69]

Originally Posted by par4tom

He's got me curious...what is the torque rating of the NP440/MY6? Not that it matters, I'm not going to be drag racing. Mainly bought this transmission for better freeway manners...

Plus...my neighbors laughed at the old SM420 I had...I had it in first and it sounded like I was going a hundred...he turned around and I was doing like 4 mph!!! HAHAHA...

Big Hat, No Cattle!

Its just below the muncie from everything that I had read, the only problems arises from the OD bushing in the front of the case ( the weal point ) if the PO had been towing heavy loads in OD it wears the case out ..oblong, you`ll know it when OD will not stay in gear there by needing overhaul. The cast iron case is not affected quite so much.

[par4tom]

Hey Brad,
The iron case trannies are relatively easy to find. Apache Auto Parts in Arizona had one that was pretty weathered, but I'm sure it could be rebuilt. Here is the pic they sent me. I think they wanted $150 bucks for the deal plus shipping...there are several others out there in the 4wd versions. Tailhousing may be a problem.

Tom

[cortcomp]

I'm at work so i can't put too much detail in here, but mine is waiting to be picked up from the rebuilders as we speak (the aluminum cased standard bolt pattern version, not the part mopar part chevy bolt pattern version.) Anyway, it's a drop in switch. You can use that special mount and all, or just bolt a hurst competition plus shifter to the side, and make your own rods.

I have another of these in my 71- pontiac tempest (t-37) It has something like 360HP and 425 ft lbs of torque....at the wheels, on the heartbreaker mustang dyno. We figured it conservatively at 430HP and 500 ft lbs of torque. I have 17" nitto wheels, posi Olds-12bolt 8.4" rear, all upgraded tubular suspension and bushings, braces, etc. It puts more hurt on taht tranny than you likely can with any truck you'll find here save the LS and big block custom guys. It holds up fine and shifts great. I don't care much for finding the correct rods, you can make them with a jack handle on your bench.

I opted for heim joints, small bolts with locktite, and B7 alloy all thread. It shifts great (the hurst comp plus shifter is amazing) and has zero slop and will never wear out the shifter bushings becaus there are none. I love this model tranny, and come across them every couple years, i've had 3 in my hands in the last 5 and sold one. You have to take a lot out to totally change speedo gears, do that with the tranny out if you can do the math with your tire size and rear gear. OD is great with 3.73 gears. Don't forget the handy integrated backup reverse light switch.

[cortcomp]

Rich is right about the case front bearing wallowing out on super hard use, tranny shops will bore that out and sleeve it with stronger material to solve it if it's an issue.

[Brad54]

Originally Posted by cortcomp

Rich is right about the case front bearing wallowing out on super hard use, tranny shops will bore that out and sleeve it with stronger material to solve it if it's an issue.

Yes, that's the standard fix from the Mopar guys... it's not a big deal, just need to be aware of it.

As for the speedo gear, if you need to change BOTH parts of it, yeah--it's a pain. I was able to do the math and find the correct drive gear and housing online--it's the same as a TH350 and 700r4 unit.
My truck has tall tires and 3.42 gears, and that OD is just sweet driving down the highway honking along at 80mph.

Since I've got a '60-'62 truck, I'm forced to use the stock bellhousing with the side mounts and hydraulic clutch. I could convert it all, but there's really no need.
So, with that said, does anyone know if there is an iron case with the Chevy-style mounting to use with a typical GM bellhousing?

-Brad

[Rich 5150 69]

Brad from all that I have read, and have not been able to confirm, iron case only came on 4x4, diesels, and or commercial....!

[cortcomp]

Same here, the iron cases i've seen have that weird housing where you need the bell with it. Since i used mine in a BOP (3.42 rear gears, big cam though so numerically lower gears would be terrible, 3.42 is just good, 3.73 would be great) i had to have the input bearing turned down to a car sized bell hole (you could do the same to use it with chevy car bell i believe.) and use the gm pattern one for my BOP bellhousing.

You do almost never find them with the shifters and can never find shifter parts, but i'd rather make my own anyways because they're fresh new shifters and less slop than facory linkage. Muncie "shift arms" work no problem. I had to "narrow" one side of the arms to get it to not rub the tunnel in my A body, but there's so much room under these trucks.

Rebuild kits are cheap for bearings synchros and everything, so the only really tough part is finding one with the gm pattern, everything else is just a little elbow grease if you can't find it. It lives up great behind this beast:

[cortcomp]

Also, if you pay attention, my BOP bell has a second bolt pattern on it that's a rectangle in portrait mode, not landscape mode like the muncie pattern. I think it's for T-10? Anyways, there are ears there on the NP440 but they're not drilled there...if your bell has both holes, and you break an ear off of the trans, you can drill through the flange and use one of the other bolt patten holes on the bell.

[Blue666]

I'm hitting the pick & pull next week. Behind which engines (diesels & 4WD's) would have had these trans? I have a couple of vehicles to look at?

[cortcomp]

if i recall 81-86? Most will be 2WD aluminum jobs like mine above, but those junkyard pics show the cast iron version and other 4wd versions. I've never seen the 4wd one in person.

[par4tom]

Cortcomp,
My experience on finding this tranny was different. I could find the cast iron and several 4wd versions, even a few aluminum ones with the Chrysler gm pattern. The one I bought in the picture above, was the only one on the entire car-parts website with this pattern. There were a couple aluminum versions but the had the combo bolt pattern as well.

Music Man found some leads on Craigslist and several were wrong listings. There was another in Montana with the correct bolt pattern, but the owner only wanted a local sale and pickup. He did sell me the shifter rods.

The tranny I got was from an 82 Chevy 1/2 ton. It seemed that GM shifted to the combo bolt pattern about 84 and later.

Hope that helps narrow your search. Good luck. Hon's in Georgia or South Carolina has a complete aluminum unit with bell housing and combo bolt pattern. They are on the car-parts website. Just make sure you look for one with side case a shifter, 2wd.
T[QUOTE[/QUOTE]
Posted via Mobile Device

[Russ.W.]

G'day all ...

Sorry to bring this post back, but I have a NP440 ID question.

What are the casting numbers on the transmission that identify it as a NP440 overdrive?

I'm trying to find one, but being in Australia, my only way to source one is via email etc through dismantler's and such in the US. Problem is, it makes it hard when they don't actually know what they're looking for. Narrowing it down by year make and model doesn't really help - especially if it's already pulled form the vehicle and sitting on a shelf with 100 others.

I need casting numbers and where to look. This way I can tell them "it will have this number on this part of the trans". All they have to do is see a number, if it's right I want it, if it's not, I don't.

Thanks for your time.

~ Russ

[ky-donzi]

Not tiring to hi-jack this thread, but why choose the np 4 speed over the easy to find nv3500 ?

[Russ.W.]

Originally Posted by ky-donzi

Not tiring to hi-jack this thread, but why choose the np 4 speed over the easy to find nv3500 ?

I have a 3 speed column shift truck, and I want to keep it column shift. The NP440 will give me an overdrive, plus I can keep the current column with the only mod needed being a separate cable for reverse.

[MusicMan70]

Russ.W. Re: Finally caught a break NP440 / MY 6

G'day all ...

Sorry to bring this post back, but I have a NP440 ID question.

What are the casting numbers on the transmission that identify it as a NP440 overdrive?

Russ, here are some of the numbers I have found; hope this helps you. Also it has 10 bolt side cover and the back up switch on the side. Try to find a complete unit with shifter. need more pics let me know. G'day!

[Russ.W.]

Thanks mate. I'll do some digging and try and make some sense out of them



Also, for anyone in New York, S K Speed are selling their entire transmission inventory.

They're only selling them in lots, ie: all the Hemi 4 speeds together, all the Muncie's together etc.

According to their website, they have 10 or so NP440's, and you can have the lot for $2,500.

If I was in the US, I'd be all over this.

http://www.skspeed.com/p.aspx?u=Manu...mission%20Shop - #15 on the list.

[Russ.W.]

Sorry for another question folks, but I have to ask it.

I realise the spline count for the input shafts are different, but does anyone know if the internals are the same between the GM and Mopar versions?

Would the Mopar gears etc still actually mount on the mainshaft, or are the a completely different diameter?

[MusicMan70]

Russ, this article says internals are the same.

http://www.customclassictrucks.com/t...n/viewall.html

[Russ.W.]

Originally Posted by MusicMan70

Russ, this article says internals are the same.

http://www.customclassictrucks.com/t...n/viewall.html

Thanks mate. Good read.



I just got a reply back from Jamie Passon of Passon Performance. I asked him the same question.

Reason I asked is, Passon makes an actual OD gearset for the Mopar trans. Not a half effort like this factory version that requires the flipping of a rod etc, but an actual dedicated gearset they make to use as a replacement. They did it for guys with original Hemi cars that wanted an OD, but didn't want to lose their numbers trans or hack up their floor for something aftermarket.

It gives them approx. the same gearing as the A727 Torqueflite, plus an OD 4th - and much, much, stronger than the factory OD trans.

He's also developed a new 5 speed giving them their standard 4 back, plus an OD 5th gear. He's built it in a case almost identical the the A833, so for those guys it's a direct replacement. Same holes, same length, same splines, same shifter location. Nothing changes.


Doing some research and I was actually quite surprised no one has ever done this for the Chevy 4 speeds (m20, m21, etc). It's a no-brainer - creating proper OD internal gearsets that is - and considering there are a million more potential GM customers than Mopar customers - I'm very surprised some snazzy business minded folk within the GM community hasn't done it.


Here was Jamie's reply:

The internals are the same. The input and output shaft have different splines and of course the case and tail are different

Are you referring to our 18 Spline OD gearset?

If so, you would need to bush 3rd gear on the mainshaft to make it work. Then there would be issues with the bearing retainer in the front. Our 18 Spline OD gearset is a larger diameter input. Therefore, it isn't going to work. You would have to have bearing retainer made custom. This is doable, just expensive.

Food for thought.

[par4tom]

Updates:

Hi guys,
I see where this thread got opened up again so I thought I'd share some thoughts on this tranny now that I've had a chance to run it a bit.

I have this behind a 420 hp 383 stroker with a 3.73 posi rear end. Let me just say, this tranny is PERFECT. The gear ratio is really nice for daily driving, with first and second gears being way better than the old granny sm420 I had. The .73 overdrive is really nice too...looking forward to better weather and some road trips to really run this thing through.

This thing bolted right up to my existing bellhousing, with no modifications needed other than a slight rerouting of the speedometer cable to reach the speedo cable input of the tailhousing. Which was no big deal. Not having to modify the bellhousing or move the clutch from the passenger side of the vehicle, was worth the extra time it took me to find this unit.

Great tranny, and I'm thankful to the guys who got me turned on to this particular model. Couldn't be happier for my application.

Tom

[Greg63]

Originally Posted by par4tom

Updates:

Hi guys,
I see where this thread got opened up again so I thought I'd share some thoughts on this tranny now that I've had a chance to run it a bit.

I have this behind a 420 hp 383 stroker with a 3.73 posi rear end. Let me just say, this tranny is PERFECT. The gear ratio is really nice for daily driving, with first and second gears being way better than the old granny sm420 I had. The .73 overdrive is really nice too...looking forward to better weather and some road trips to really run this thing through.

This thing bolted right up to my existing bellhousing, with no modifications needed other than a slight rerouting of the speedometer cable to reach the speedo cable input of the tailhousing. Which was no big deal. Not having to modify the bellhousing or move the clutch from the passenger side of the vehicle, was worth the extra time it took me to find this unit.

Great tranny, and I'm thankful to the guys who got me turned on to this particular model. Couldn't be happier for my application.

Tom

I did the same thing this past August and I totally agree with everything you said.
Greg.

[zetan]

I have one of these New Process 833s (RPO code MY6) behind my GM 6.2L diesel.
It has a lot better drive ability than the SM465 granny low manual trans.
I have the 4wd version as well with the round-6 bolt adapter to tcase hanging off the back, but it needs a new input bearing retainer.

Here is a detailed article about it
http://zetan.cc/van/np833/

1975 thru 1987 Overdrive 3.09:1 - 1.67:1 - 1:1 - 0.73:1

The transmissions is rated at 270 ft-lbs. torque.

[cortcomp]

On the backside, where i marked in red, upside down it reads "C-15390" and has the New Process logo above it (below it if you're reading the words right side up and the tranny upside down.) The logo is an N and a P grafted together, inside of a gear.

Honestly, i'm doing mine because i have it, and because someone cut my floor for a side shifter 3 speed conversion, and this should line up in that same hole. If i was doing it from scratch, and didn't have a tranny, the 5 speed really is the way to go. shifts smoother, no wide gear gap, more available, etc.

[cortcomp]

"Doing some research and I was actually quite surprised no one has ever done this for the Chevy 4 speeds (m20, m21, etc). It's a no-brainer - creating proper OD internal gearsets that is - and considering there are a million more potential GM customers than Mopar customers - I'm very surprised some snazzy business minded folk within the GM community hasn't done it."

I don't have any links, but that for sure has been done with muncie trans by at least one but i think several companies. The main problem you get into with all this is cost. Well, two problems, cost and strength. Any time you do OD like you do on the NP440 or muncie conversion, you are transferring power differently through the trans than say a 5 speed with a planetary setup. It creates the issue of wallowing out or thrust wear on one of the shafts, when you put lots of power to it AND you have traction. In my truck, the 327 will be stock and not have power. In my t-37, i have power but street tires so it doesn't really hook up (and i'm a cruiser anyways, bad a$$ as i pretend to be). So, you end up with a transmission that has wider ratios than a 5 speed, the linkage can by annoying to adjust and maintain, and even when you get it perfect, isn't quite as amazing as a trans where the shifter connects right inside the top. Lastly, to do the muncie conversion, it was like a grand. Then you have a grand to get a muncie in great condition. For that price you can get a nice 5 speed setup.

A lot of guys live gear vendors OD unit and that's nice but it's more work and all that and i prefer an all in one average setup.
There are really two ways to go with these projects in my book, IF YOU ARE GOING TO DROP LIKE 2K, and if you are making decent power. (this doesn't apply to my A-body, because to look and seem normal it needs a side loader and the NP440 is great for a bodies with big torque in my opinion, because they look right and most factory parts fit them, hurst shifters, etc.)

Either get one of those 5 speeds that 5th is 1:1 and you pick a high gear out back like 2.74, which makes your RPMS like you have OD but you have 5 gears to tear it up with so you get the acceleration of having 3.73s, or get a T5 or tremec or something 5 speed that has OD in it. For the money you'd put in a muncie conversion, you have a transmission you're afraid to lean on because you might break it . On the T5/tremec.etc parts are just around. On the NP 440 you can get gears and parts and sleeve that wallowed out case problem and rebuild.

So for me, stick shift and OD being the project:

1K and under: NP440 hands down. Freshen it up, get a new shifter and make your shift rods nice and smooth and no slop, and you'll love it.

Spending over 1k?: Go T5 or something top loader and be done with it.