A833MY6

[kb426]

Does anybody know details about the MY6 trans?

[enjenjo]

Most commonly found in C10 trucks. What do you need to know?

[kb426]

Frank, so far I haven't been able to find any GM info, only Dodge. What bellhousing does this take? Would this be a simple replacement for a 4 speed in my friends 58 corvette? After what Charlie said about a t5 conversion, it would be nice to find a simple somewhat economical overdrive solution for him. If there's anything that I need to know, it will be much appreciated.

[enjenjo]

Okay, here goes. It's based on the old A833 New Process trans used in Mopars in the 60s. But it has an all aluminum case, which is not as strong as the steel case. I have used them behind a BBC with no problems. There are two versions of this, early and late. Between the two they covered from 1980 to 1986

The early version will bolt to a standard Chevy bell housing using the stock clutch and throw out bearing. The only problem on it, the pilot on the front bearing retainer is about 5.125", and I believe that  the Vette will be 4.6875" You may be able to cut down the bearing retainer to the smaller diameter, but you may have to change to Allen bolts to clear the bolt heads. Or, you can find a truck bell housing with the 5.125 pilot and use that.

It's the same length as a Muncie 4 speed, and has the same output spline. The shifter position is slightly different, but a Muncie shifter will fit, after modifying the rods.

It is a true overdrive, which is done by making the original 4th gear the new third gear, and installing OD gears in the 3rd gear position. So the 3rd/4th lever on the box is installed upside down so the shift pattern remains the same. Ratio spread is about the same as a 700R4.

Now to the later model. It has a unique bolt pattern on the bell housing, unlike anything else. the bottom bolts are the same as a regular Chevy trans, but the top bolts have been moved. I am told that some bell housings can be plugged and redrilled to match, but it would be easier to just get the right bell housing.

[Digger]

There is a bunch of stuff on the Corvette Forum about this trans.
Google MY6 transmission and one of the headings says Corvette Forum
MY6 trans swap into 65 coupe.

[kb426]

Does the version used in the Dodge pickups share dimensions with the Chevy version?

[enjenjo]

Does the version used in the Dodge pickups share dimensions with the Chevy version?

No, the whole front end is different, different length tailshaft. Some of the internal parts are the same, but that is about it.

[kb426]

Thanks, guys. We have a beginning. I found a trans shop that has a used one. Now I have enough info to start asking questions.

[GPster]

This may or may not be in your interest. It was in this week's bargain shopper. SN465     four speed trans out of an '85 Chevy C30 truck. Includes bell housing, clutch and flywheel. $200.00 After '84 I never paid any attention to any trucks other than Ford Rangers but following the replies the truck bell housing and flywheel for the crank with the old style rear main seal had me guessing. Just to let you know that I'm still here paying attention. This cold/gray weather is overwhelming my anti-depressant medicine. GPster

[wayne petty]

http://www.customclassictrucks.com/techarticles/0905cct_a883_four_speed_overdrive_transmission/viewall.html



a gm parts list for it..

http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=426466

a great list of transmission gear ratios

http://www.vibratesoftware.com/html_help/2011/GM/gm_transmissions.htm

just thought i would add a few links...

W

[406Rich]

The my6 also designated NP-440 trans, as they said 1979 to 86 mainly used in GMC both gas and deseil, made in aluminum and cast iron, if you end up with the aluminum case it may or may not have the the front bearing support for the fourth gear wallowed out, due to towing or pulling heavy loads, they do sell a repair bushing for it. Herew is a thread from the Gasser site to install the mopar trans, the A833 behind chevy. thanks to Casey for the info.
Ok guys, I got asked to post what mods is necessary to put a mopar 4 speed behind a chevy engine. You will need an adapter plate to begin with that bolts to mopar trans and in turn the adapter bolts to the chevy bellhousing. The one i have is a vintage Lakewood piece from the 70's and has been out of production for years. The only place i know of to get one is from passon performance, I have talked to Jamie Passon before and he says they have the plates.
You will need to cut 3/4 inch off the pilot on the input shaft and then turn down the remaining pilot to fit a chevy pilot bushing. The next step, which is where I'm at right now is getting the chevy TO bearing to fit the mopar bearing retainer snout. The chvery bearing has a larger ID then the mopar. My buddy has done this b4 so it wont be a big deal. Take some fairly thick walled tubing that fits the mopar snout snug enough that it has to be pressed on. The turn it down in the lathe to fit the chevy bearing. I haven't asked, but Passon may carry a bearing retainer already setup this way to simply things.
Now of course you will have to modify the crossmember in your ride to accomadate the mopar trans. I will post pics of mine for my 64 impala as soon as i can. I had to remove material from the front of the crossmember to clear the main case on the trans. Then I took some 1/4 in flat and welded it to the x member and bolted it to the trans. Plate was about 8 inches long and 6 inches wide but will depend on your app.
I was able to use the factory chevy rear trans mount, just had to come in 1.25 inches on each side and drill new holes. Bolted to the mopar trans perfectly but took a wrench to do this because clearance gets pretty tight.
Last you will have to mount the trans in the car to locate where the shifter placement will need to be. I built my own bracket based off a picture of the bracket that was used by mopar in some B body bench seat apps.
Guess that does it guys, any ? just ask, I'm always glad to help and I will get some pics up as soon as i can get my lovely wife to take them