3rd Member Question

[Hazdri]

Need some assurance that I am doing the right thing. I haven't messed with the backside before so this is new ground I am treading. Any insight would be appreciated.

Took everything apart this past week and the ring and pinion are shot. Everything else looks ok(Axles, carrier, etc.). I found a set from a guy that bought a mustang and he took them off because he wanted a 3.25 in his. They are FOMOCO C80W-4601-A C80W-4210-A 3.91(?). You can see where the bearing were pressed and the carrier bolts attached. Other than that, they look brand new. The ring still has the marking compound on the teeth. He told me that they were put together by the previous owner but never installed the case into the housing.

I have looked online and through my books but can't find much information on this setup. It looks like everything matches up and should work but I am just wanting to make sure before I put everything back together. I guess I am trying to clear any doubts.

[bruceandersson]

I'd verify the lash. If it is off you will just chew it up. Also verify your axles have the same number of teeth as there are 28 and 31 spline versions.

[64 f100]

If, the third member was set up right then you have no problem. You don't say what ratio is in your truck at the moment, nor how much he wants for the third member. Lots of ifs here. These trucks were low geared from the factory for a working vehicle Are you going to work this truck or pull anything? What engine and transmission are your running? 391 ratio would be great if your planning on pulling a house off the foundation, or maybe drag racing , but is going to be terrible for fuel mileage. If, I were you I would look for something closer to your original ratio or maybe one step higher and not lower. Used third members can be had for 50 to 125 as a general rule. Of course that is used. I have several I could sell but most likely I am not close enough to do you any good, southern IL..

Rich

[Hazdri]

I'd verify the lash. If it is off you will just chew it up. Also verify your axles have the same number of teeth as there are 28 and 31 spline versions.

My yoke is 28 spine and it fits on the pinion. I'll check the lash when I get it all together. Thanks

If, the third member was set up right then you have no problem. You don't say what ratio is in your truck at the moment, nor how much he wants for the third member. Lots of ifs here. These trucks were low geared from the factory for a working vehicle Are you going to work this truck or pull anything? What engine and transmission are your running? 391 ratio would be great if your planning on pulling a house off the foundation, or maybe drag racing , but is going to be terrible for fuel mileage. If, I were you I would look for something closer to your original ratio or maybe one step higher and not lower. Used third members can be had for 50 to 125 as a general rule. Of course that is used. I have several I could sell but most likely I am not close enough to do you any good, southern IL..

Rich

Good points. I've got a 352 with a NP 435 and I HAD a 3.00 but I'm not sure if that was original ratio with my truck. The axles are 28 spline. My ID plate doesn't have anything printed on the axle section. I'm assuming that it is the original but you know how that goes. I already purchased them and got a good deal figuring if I change my mind I shouldn't have problem getting rid of them. I kinda like the idea of pulling a house down the road but I probably will be just driving around town and weekends. I'm not terrible worried about MPG unless we are talking a dramatic decline. I've seen some complete thirds around here for around 100.

I just want to be sure that I'm not missing something by putting this ring and pinion in and fouling something up.

Thanks for y'alls help.