Finally caught a break NP440 / MY 6

[Dazzoman]

Originally Posted by 65Robb

Ok awesome haha

Right on Drako thats right .
One thing I regret is that I could have reused my old zerked U joints and here it is :
U joints that were made pre 1990s were made better and lasted longer and/but the drive line specialists might say "If they have zerk fittings thats weaker , 'BAD' plus these new non zerked joints are made to go over 100k miles without having to grease them " .
Well they are half right about the strength with the zerks but what they won't tell you ( so they can sell more ) is that you can use your old ones and they are just as strong .
You WILL have to use an new front smaller joint AND it HAS zerks !
But don't worry , it will not break .

[65Robb]

Ok sweet great info guys I'm thinking once I get the slip.yoke in ill replace all u joints and carrier bearing just so its done and won't have to worry about them for a long time.

[Dazzoman]

Originally Posted by 65Robb

Ok sweet great info guys I'm thinking once I get the slip.yoke in ill replace all u joints and carrier bearing just so its done and won't have to worry about them for a long time.

I meant if you have USA made pre 90s u joints with zerks YOU SHOULD RE USE THEM .
Otherwise if you just get the new ones (without zerks ) you are at a dis advantage because they last about 100k whereas the old style are better .
They were still into making things last when they made em .
Ya you have to grease em once and a while but they will outlast the new .

[trailcarnage]

I am so hoping that somebody in this thread can help me out...

I recently picked up one a MY6 that I am going to mount behind my LT1 in my C10. I know that the LT1 uses a 153t flywheel and a 10.4" clutch with a T56. It looks like the '84 C10 that this trans came from uses a 11" or 12" clutch. I am trying to determine what flywheel and clutch to order to this combo.

Any advice would be greatly appreciated!

[par4tom]

I have a 168 tooth ring gear on mine...
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[Captainfab]

What is the input shaft spline count on the MY6 versus the T56?

[Dazzoman]

Originally Posted by trailcarnage

I am so hoping that somebody in this thread can help me out...

I recently picked up one a MY6 that I am going to mount behind my LT1 in my C10. I know that the LT1 uses a 153t flywheel and a 10.4" clutch with a T56. It looks like the '84 C10 that this trans came from uses a 11" or 12" clutch. I am trying to determine what flywheel and clutch to order to this combo.

Any advice would be greatly appreciated!

Do the flywheel bolt hole pattern(s) line up so far when you put it on ?
If not then you have another question .

[trailcarnage]

Originally Posted by Captainfab

What is the input shaft spline count on the MY6 versus the T56?

MY6 is a 1.125"x10T while the T56 is a 26T spline. A bonus is that they share the same pilot bearing part number.

[trailcarnage]

Originally Posted by Dazzoman

Do the flywheel bolt hole pattern(s) line up so far when you put it on ?
If not then you have another question .

I don't know yet as I don't have one. I pulled the trigger today and ordered an LT1 flywheel and '84 C10 clutch. That will tell the tail.

I found a fellow on another board who installed a T56 behind a '87 SBC using the LT1 flywheel and T56 clutch. It really sounds like the Gen I & II bottom ends are near identical. The reverse flow cooling and timing seems to be the big difference.

[par4tom]

Originally Posted by trailcarnage

MY6 is a 1.125"x10T while the T56 is a 26T spline. A bonus is that they share the same pilot bearing part number.

When I swapped out the SM420 original 4 speed for this transmission, I was able to bolt the MY6 to the bell housing in place of the original 4 speed without any problems or modifications.

My existing clutch off the old sm420 fit perfectly and was practically new so all I did was install a new pilot bushing (Identical as the original) and install a new throw-out bearing (identical as the original as well).

This is a very simple swap...

[Dazzoman]

Wow exellint !
Mine had bolt ears on one side that bolted on perfect but the other side (L) was an different pattern , had to use the straps .
Maybe all this time I had the wrong transmission and there are more MY6 's out there with differences . I don't know for sure .
Or maybe your bell housing is different . Again I am not sure but .

[par4tom]

There are at least 2 variations of this transmission . If you look at the picture on my very first post on the first page, this is the bolt pattern for the aluminum cased transmission. There is a Chrysler pattern that is in their cast iron cased transmissions that is squared off.

The aluminum version will bolt right up to the older style bellhousings like mine. The cast iron versions are different and I understand came out of the GM 4x4 vehicles of the 80's...
Tom
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[Dazzoman]

Where did you say ( or can I see please ) the pictures were ?
Are you saying I didnt have to do all that retro fitting with bracket straps after all ?
My trans is the 1982 cast iron model .

[trailcarnage]

I picked mine up for $150 including shifter and aluminum bell housing. The PO did break one of the bosses for the shifter mount. Any ideas for repair besides welding?

[par4tom]

Here is a picture of the NP440 ALUMINUM cased transmission that is the same transmission I put in my truck. This is the exact same bolt pattern as the SM420 original transmission.

Literally, you can bolt this up and its ready to go...the second picture shows my bell housing with the passenger side clutch fork and the two bolts for the hydraulic clutch slave cylinder. No modifications were needed...

Tom

[Dazzoman]

Freaking beautiful !
I am amazed I had to go thru all that to get it to work and all this time I could of had it so much easier .
I guess the good news is that if there is ever an shortage then the other weird one ( like what I have ) can be retrofitted .
The other thing is that mine is the cast iron model ....
So
Did they make them in cast iron like yours with that bolt pattern is a great question ?

[Chevystep]

Has anyone come up with a good source for speedo gears for this tranny? I've bolted one up behind my 283 and love it. But I still haven't found the right speedo gear, could also use the speedo cable case O-ring....

[par4tom]

Originally Posted by Dazzoman

Freaking beautiful !
I am amazed I had to go thru all that to get it to work and all this time I could of had it so much easier .
I guess the good news is that if there is ever an shortage then the other weird one ( like what I have ) can be retrofitted .
The other thing is that mine is the cast iron model ....
So
Did they make them in cast iron like yours with that bolt pattern is a great question ?

I don't think they do...at least I have never seen one and don't recall anyone else ever saying they had a cast-iron version with the Muncie bolt pattern...

[par4tom]

Originally Posted by Chevystep

Has anyone come up with a good source for speedo gears for this tranny? I've bolted one up behind my 283 and love it. But I still haven't found the right speedo gear, could also use the speedo cable case O-ring....

You can find different gears online. This tranny uses the same gears as the old Turbo 350's. If you give any transmission shop your differential ratio and the height of your tires, they have charts that will tell them which gears to get.

Be advised, you will have to pull the whole transmission and the tail housing in order to install the gear.

Or...if you don't want to spend the money, go to the Apple App store and get the "Waze" app...its free and tons better than Maps. Plus, it uses GPS to plot your speed, keep track of the cops and traffic...cheap fix but it works!

Tom

[Dazzoman]

Originally Posted by Chevystep

Has anyone come up with a good source for speedo gears for this tranny? I've bolted one up behind my 283 and love it. But I still haven't found the right speedo gear, could also use the speedo cable case O-ring....

I went to summit and got the regular mechanical one but a tad longer than the original by about 12 inches .
Its a little choppy at times but pretty good for China made .

[Chevystep]

Originally Posted by par4tom

Be advised, you will have to pull the whole transmission and the tail housing in order to install the gear.

Tom

I thought the gear was right behind the speedo cable plate below the shifter, the plate with the fork holding it on?
On another note, if you can't find the OE GM shifter knob, you can always have a Hurst like one made-since it is a Hurst unit anyway!

http://www.epcomfg.com/

[trailcarnage]

So, I have to pull the tail housing so I can get the shift mounting bracket lug welded and tapped. While I have it off I may as well rebuild. Any thoughts on this kit?http://www.ebay.com/itm/191336459496

[Blue666(2)]

Here's an 833 less than a grand.

https://indianapolis.craigslist.org/pts/6123842202.html

[Brad54]

Some answers to questions:
Speedo gear: same as the Th350. This is a two-part gear: the one that goes on the end of the speedo cable, and the one that is "attached" to the output of the trans. You pull the speedo cable "port," and replace that gear. They're colored for reference. You shouldn't have to change the gear that's part of the output of the trans--so you won't have to pull the tail shaft housing.
Mounting patterns, aluminum and iron case:
The aluminum case has two different mounting patterns; one is like the standard Muncie pattern and bolts up to our stock bellhousings. The other has one side squared off like a Mopar, and requires the factory re-tooled aluminum bellhousing.
That bellhkusingndoesnt have side mounts--it's like a later Chevy bellhousing, but with the funky mount.
There are two different aluminum bellhousings:
One with regular mechanical linkage, one with a boss for a hydraulic slave cylinder to push the clutch fork.
Input shaft lengths and diameters are all standard GM, so the original throw out bearing and clutch disc works.

[Blue666(2)]

Originally Posted by Brad54

Some answers to questions:
Speedo gear: same as the Th350. This is a two-part gear: the one that goes on the end of the speedo cable, and the one that is "attached" to the output of the trans. You pull the speedo cable "port," and replace that gear. They're colored for reference. You shouldn't have to change the gear that's part of the output of the trans--so you won't have to pull the tail shaft housing.
Mounting patterns, aluminum and iron case:
The aluminum case has two different mounting patterns; one is like the standard Muncie pattern and bolts up to our stock bellhousings. The other has one side squared off like a Mopar, and requires the factory re-tooled aluminum bellhousing.
That bellhkusingndoesnt have side mounts--it's like a later Chevy bellhousing, but with the funky mount.
There are two different aluminum bellhousings:
One with regular mechanical linkage, one with a boss for a hydraulic slave cylinder to push the clutch fork.
Input shaft lengths and diameters are all standard GM, so the original throw out bearing and clutch disc works.

Brad, do you know if a hydraulic clutch can be used with a trans originally set up for a mechanical clutch? Any info as to which part numbers would be needed? Thank.