Want to see pics of gov. locker in CUCV's

[dependable]

For any differential, even if you can not find stampings, you can figure out gear ratio by dividing number of pinion teeth into the number of ring gear teeth. .

 

[kurtkds]

You will probably have 4:11 gears then, which is a good all around set of gears.

 

[aboonski]

Gov Loc & gear ratios

Just got another 12 bolt rear with the Gov Loc inside. I pulled the thing apart tonight and everything looks like new inside. Ring gear has 44 teeth, pinion 14. Sounds like a high ratio to me! Now that I have two of these 12 bolt rears with the Gov Loc, would they be worth the trouble to install into an M1009? I'll post some pictures. I still have the 79 K5 with the granny 4 speed that I plan to dismantle and part out pretty soon. This one even has the factory roll bar in the bed of the truck and a tachometer in the dash. Can't deal with gas motors anymore!

 

[11Echo]

Just got another 12 bolt rear with the Gov Loc inside. I pulled the thing apart tonight and everything looks like new inside. Ring gear has 44 teeth, pinion 14. Sounds like a high ratio to me! Now that I have two of these 12 bolt rears with the Gov Loc, would they be worth the trouble to install into an M1009? I'll post some pictures. I still have the 79 K5 with the granny 4 speed that I plan to dismantle and part out pretty soon. This one even has the factory roll bar in the bed of the truck and a tachometer in the dash. Can't deal with gas motors anymore!

Look again. the ring gear is a 43. It's called a 3.07 gear ratio.

 

[AJMBLAZER]

That would make it a swap candidate for the stock 12 bolt if you felt like doing it.

 

[aboonski]

For some reason I thought the M1009 came with a 10 bolt rear differential. My M1008A1 has the 14 bolt Detroit Locker which is as good as it gets. Eventually I hope to acquire an M1009 and will save up the parts I need to make it heavier duty. The 12 bolt rear axle out of the 79 K5 looks like it will bolt right in but not sure about the yoke for the driveshaft. Plenty of machine shops in our area can take care of that if I need to modify a shaft. Just wondering what breaks on the Gov Loc?

 

[aboonski]

Thanks for bringing the 43 to my attention. My eyes are getting pretty bad these days! I had a problem with a detached retna in my right eye so my eyesight will never be the same as it once was. Glad I took the macro of the ring gear numbers!

 

[AJMBLAZER]

The M1009 does have 10 bolts front and rear. The 12 bolt is an upgrade. Not a huge upgrade but it is an upgrade.

 

[DMgunn]

This is so obvious, but I will add anyway - the best way to count teeth is to take a paint pen and make a mark BETWEEN two teeth. That way you don't forget when to stop counting. Most people mark a tooth, then by the time they get back to the mark, they can't remember if the marked one was already counted . That is how you end up off by one tooth.......

Something no one has mentioned - the other major fault of the Gov-Pop...err Lok, is that it takes a bit of time to engage. I've seen many people, even older conservative drivers, whose first instinct after starting to spin is to floor it. Nice plan - now you have one tire spinning at 60 mph just in time for the gov-lok to engage. Pop!

 

[aboonski]

That's a great bit of advice DMgunn! I know I made the mistake when I counted the teeth. The 3:07 gear ratio is kinda high for the CUCV but fuel economy would increase a little. Now I will have to see what is in the 79 K5 differential which will probably be lower due to being a "trailering special" Cheyanne version of the Blazer. I hope to take components from my M1008A1 parts truck and the 79 K5 to make myself an M1009 clone out of an 89 GMC Jimmy. It has to do with finances more than anything.

 

[AJMBLAZER]

The M1009 has 3.08 geared 10 bolts. So the 3.07 geared 12 bolt you have is basically the same gearing as what a M1009 has.

 

[aboonski]

That's great information to know! Looks like you could almost bolt this one into an M1009 ; unfortunately I pulled the guts out of the differential before knowing this (I like to take things apart). The frame with the front and rear differentials is going for scrap tomorrow or Friday for sure. I am leaving the carrier in the front differential because it would take a ton of work to remove the axles - lots of serious rust on the knuckle bolts (or king bolts whatever they are called). Since there is so little difference in the ratio between the stock M1009 and the 3.07, what would happen if you used four wheel drive (off road only) with the two different ratios? Such a slight difference should not be a big deal so long as you were not on dry pavement.

 

[Jake0147]

T
Since there is so little difference in the ratio between the stock M1009 and the 3.07, what would happen if you used four wheel drive (off road only) with the two different ratios? Such a slight difference should not be a big deal so long as you were not on dry pavement.

When chevy went to IFS trucks they had greater differences than that straight out of the factory. Flatlanders come up here and drive them in four wheel drive from the first snowflake to the end of mud season, which while "wintery" all winter, truely entails about ten percent (tops) of driving being on roads that are anything less than dry. You'll get more difference in rotations from having a tire just a couple of pounds less than the other three.

 

[AJMBLAZER]

Yeah, 3.07 and 3.08 aren't really different ratios. Remember it's all rough math with some advertising thrown in and there is about a 5% difference that can be tolerated (if I'm remembering it right).

For example in the "4.10's" area there's 4.09's, 4.10's, 4.11's, and 4.12's and I think I've even read a 4.08 referenced. All work with each other and it just depends on which axle, which gear set, etc etc etc determines which gears you get.

So in other words the front and rear axles don't have to match perfectly. 3.08 and 3.07 are just fine.

Also, it should bolt in but you'd need new rear U bolts meant for the 12 bolt equipped Blazer and a conversion U-joint. I THINK the brake lines bolt in but don't hold me to that.

 

[hobie237]

Just for fun:

3.07 = 43/14
3.08 = 40/13
...
3.300 = 33 / 10
3.308 = 43 / 13
3.333 = 20 / 6
3.333 = 30 / 9
3.333 = 40 / 12
3.333 = 50 / 15
3.357 = 47 / 14
3.364 = 37 / 11
3.375 = 27 / 8
3.375 = 27 / 8
3.385 = 44 / 13
3.400 = 17 / 5
3.400 = 34 / 10
3.400 = 51 / 15
3.417 = 41 / 12
3.429 = 24 / 7
3.429 = 48 / 14
3.444 = 31 / 9
3.455 = 38 / 11
3.462 = 45 / 13
3.467 = 52 / 15
3.500 = 21 / 6
3.500 = 28 / 8
3.500 = 28 / 8
3.500 = 35 / 10
3.500 = 42 / 12
3.500 = 49 / 14
3.533 = 53 / 15
3.538 = 46 / 13
3.545 = 39 / 11
3.556 = 32 / 9
3.571 = 25 / 7
3.571 = 50 / 14
3.583 = 43 / 12
3.600 = 18 / 5
3.600 = 36 / 10
3.600 = 54 / 15
3.615 = 47 / 13
3.625 = 29 / 8
3.625 = 29 / 8
3.636 = 40 / 11
3.643 = 51 / 14
3.667 = 22 / 6
3.667 = 33 / 9
3.667 = 44 / 12
3.667 = 55 / 15
3.692 = 48 / 13
3.700 = 37 / 10
3.714 = 26 / 7
3.714 = 52 / 14
3.727 = 41 / 11
3.733 = 56 / 15
3.750 = 30 / 8
3.750 = 30 / 8
3.750 = 45 / 12
3.769 = 49 / 13
3.778 = 34 / 9
3.786 = 53 / 14
3.800 = 19 / 5
3.800 = 38 / 10
3.800 = 57 / 15
3.818 = 42 / 11
3.833 = 23 / 6
3.833 = 46 / 12
3.846 = 50 / 13
3.857 = 27 / 7
3.857 = 54 / 14
3.867 = 58 / 15
3.875 = 31 / 8
3.875 = 31 / 8
3.889 = 35 / 9
3.900 = 39 / 10
3.909 = 43 / 11
3.917 = 47 / 12
3.923 = 51 / 13
3.929 = 55 / 14
3.933 = 59 / 15
4.000 = 20 / 5
4.000 = 24 / 6
4.000 = 28 / 7
4.000 = 32 / 8
4.000 = 32 / 8
4.000 = 36 / 9
4.000 = 40 / 10
4.000 = 44 / 11
4.000 = 48 / 12
4.000 = 52 / 13
4.000 = 56 / 14
4.000 = 60 / 15
4.067 = 61 / 15
4.071 = 57 / 14
4.077 = 53 / 13
4.083 = 49 / 12
4.091 = 45 / 11
4.100 = 41 / 10
4.111 = 37 / 9
4.125 = 33 / 8
4.125 = 33 / 8
4.133 = 62 / 15
4.143 = 29 / 7
4.143 = 58 / 14
4.154 = 54 / 13
4.167 = 25 / 6
4.167 = 50 / 12
4.182 = 46 / 11
4.200 = 21 / 5
4.200 = 42 / 10
4.200 = 63 / 15
4.214 = 59 / 14
4.222 = 38 / 9
4.231 = 55 / 13
4.250 = 34 / 8
4.250 = 34 / 8
4.250 = 51 / 12
4.267 = 64 / 15
4.273 = 47 / 11
4.286 = 30 / 7
4.286 = 60 / 14
4.300 = 43 / 10

Obviously, not all of these would be practical or feasible depending on the actual sizes of the gears, strengths, etc. Also, obviously more ratios are possible that aren't listed here.

 

[DMgunn]

If you are going to build a M1009 clone, I have a data plate (the shipping one with all the external dimensions on it) for one that could help complete the illusion......

 

[aboonski]

Thanks for the offer DM but my M1008A1 has an M1009 data plate on the door that I have to swap with the correct plate for the truck. It's great to see that parts are so easily interchangeable with the CUCV! The ratio listing that Hobie237 just posted is really nice to have for future reference. I will be checking out the ratio of the differentials in that '79 K5 in a few minutes so I will not have to do the math to figure out the ratio once I read the ring gear. I did figure out how to remove the front axles and wound up pulling them out of the soon to be scrapped K5 frame; also kept the front gears as well. Will post a picture or two of everything an hope it will be of use to another member. I am guessing the 10 2 72 stamped into the ring gear indicated the date of manufacture. Also noted the part was a DANA - I think the rear differential had GM stamped into it.

 

[aboonski]

Pulled the cover off the front differential in the 79 K5 and took a picture of the ring gear - looks like 41 teeth on the ring and 14 on the pinion - ratio should be 2.93 very high and I am surprised they had this ratio in a vehicle used for hauling trailers! I imagine they depend on the granny gear to get the ball rolling. There's a Gov Loc in this one too (in the rear differential that is).

 

[bigflew]

can you put a gov loc in the front diff of a 1009? when I bought mine I thought they had them in front and rear. then I joined this site and got smart now the truck is in my garage in a thousand parts with way too many ideas of what to do to make it a lot better than new.
if you can put a gov loc in front where can i get one.

 

[hobie237]

Having a front limited slip won't be good for steering, nor will it be great for tire wear. Air or electric lockers would be better solutions. Well, really, anything is better than a gov-bomb.