Putting in a posi diff on a 79 with 3.73 gears

[chevybig10]

One question for putting in a posi lock diff on my truck.

Right now I have one wheel drive, no limited slip or nothing. So if I put in a posi lock, and if the other truck had a different gear ratio can I still put it in my truck?

By this I mean Will I have to change over the whole cluster and therefore not have matching gears OR Take off the ring gear from mine (Ring or crown...the biggest one on the cluster I am not sure of correct word) and swap the ring onto my cluster?

I am not sure about how posi works, I have a basic understanding only, but Iw as hoping to just pull the retaining bolt, pull the pin, c clips, axles, and then take off the caps and bushings and put in the new one with posi....or only have to put my ring gear on the new cluster.

Anyone know the real answer or truth to this one?

Thanks a lot!
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[maverick3656]

is your truck 2 or 4 wheel drive?

[chevybig10]

Two wheel drive.

[maverick3656]

it may be best if you just change the whole axle. you can pick up one at a junk yard with posi, cheap sometimes.

[chevybig10]

Nah, If I change the whole axle I would do the bearings, seals, new brakes, and an entire diff kit with all the pinion seal and bearing etc.

I just want to see if I can put in a posi that I am getting for free that runs well. I am not sure of the ratio though so that is why I am asking.

If I can't do it with a different ratio I will buy one new and put out the dough and do it all up right rather than half assed. I just want to know if it will work if it happens to be a different ratio before I take it all apart.

[90Accord]

what the other axles gear ratio?

[chevybig10]

I am not sure of it yet. It is being pulled out of a truck by a friend of mine that is out of town. He just cut the springs to pull it, so I am unsure of the gear ratio.

this is more of a precaution if it is different.

[90Accord]

the worse thing that is going to happen, will be a speedometer difference, without knowing the ratio i cant tell you the exact difference but i can tell you it will exist, as long as its from the 73-87 generation i dont see any problems putting in your truck so as long as your speedo being a few percent off its not going to be a ground shaking installation