The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Engine & Drivetrain

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-12-2019, 03:37 PM   #1
HO455
Registered User
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 5,759
NP440/MY6 (Chevy 4 Speed w/Overdrive)

Is anyone familiar with this transmission? One for sale kinda local and I was wondering it it would be worth the trip north.

https://seattle.craigslist.org/sno/p...929681217.html

Ad reads as follows:
This is for an NP440 transmission that I recently rebuilt. Price is firm. This is a rare transmission used in some chevy trucks during the 80s. The chevy RPO code for this transmission is MY6. This is a chevy 4 speed with 4th gear being overdrive. There were two options for this transmission 4wd and 2wd. The 4wd transmissions got the cast iron case while the 2wd transmissions got an aluminum case. I took a 4wd case and converted it to 2wd with an aluminum tailshaft and 2wd mainshaft. This is the strongest way this transmission can be built in 2wd. I already have one of these in my car and I do not need this one. This transmission has a 27 spline output shaft tooth count and you can use a TH350 transmission crossmember to mount this transmission. This transmission uses a hybrid chevy chrysler bellhousing bolt pattern. This comes with the correct bellhousing. It also comes with a bellhousing to block spacer if you want to use a hydraulic throwout bearing. This transmission has almost the same gear ratios as a 700R4 transmission. If you want to keep a manual transmission and give your hotrod/truck overdrive that is decently strong and will not break the bank here is your chance.


NP440 Gear Ratios:
1st: 3.09
2nd: 1.67
3rd: 1.00
4th: 0.73

Input Shaft Spline: 10 Spline
Output Shaft Spline: 27 Spline
Flywheel Diameter: 11 inch flywheel will fit
Clutch Size: 11 inch clutch will fit
Speedometer Drive Gear: 17 Tooth Red Gear (Part #8640517)
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F3 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is offline   Reply With Quote
Old 07-13-2019, 07:19 AM   #2
tkeduk8r
Senior Member
 
tkeduk8r's Avatar
 
Join Date: Apr 2001
Location: Alexandria, MN
Posts: 1,402
Re: NP440/MY6 (Chevy 4 Speed w/Overdrive)

They didnt make alot of these.... i have one for a future project and a spare for parts.... i have only ever seen three in junked trucks in the past 20 years. Its a muncie 4 speed look with od. If you trust the guy and his rebuild skills, id think about it, since the price of a rebuilt anything else is gonna be a fair amount more. Jmo.
Mike
__________________
63 C20 2WD, 230/SM420/4.11 73K
68 C30 dump truck, 327,SM425,4.56 66K original
68 C10 2WD SWB Stepper, 250/3-tree/3.73 66K.... Wifes
68 Buick Skylark Custom Conv., 350/TH400/2.56 In our family since '79
69 GMC 1500 SWB 2WD, 350/TH350/3.73 posi...
70 K10 SWB 4X4 4-sp,ps, pb, tilt, buckets, console, sliding back window (Need AC parts) WIP
72 Chevy K20 4x4 350/350/205/4.56 donor
72 Vette 350/M21/3.70 posi, triple black and super fast
84 Olds Cutlass Brougham 350/2004r/4.11 was Dad's
tkeduk8r is offline   Reply With Quote
Old 07-13-2019, 02:13 PM   #3
HO455
Registered User
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 5,759
Re: NP440/MY6 (Chevy 4 Speed w/Overdrive)

Thanks for the Information. Now its decision time.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F3 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is offline   Reply With Quote
Old 07-16-2019, 06:01 PM   #4
Tom
driving is in my blood
 
Tom's Avatar
 
Join Date: Dec 1999
Location: Mesa AZ
Posts: 4,912
Re: NP440/MY6 (Chevy 4 Speed w/Overdrive)

Theres like a 30 page discussion on these in the 73-87 forum. Everything you ever need to know.
They are a Chrysler transmission. They are fine with stock engines. They are not high performance units.
__________________
-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle.
-98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes.
-02 Suburban 4x4: stock
-CBR600F4i, CBR600RR, CBR1000RR, and standup skis
DISCLAIMER: I cant spell for the life of me.
Tom is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:38 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com