The Stovebolt Site Forums The Shop Area Driveline confused?!?!

hey gang, really confusing rite now took rear apart axle splines are 17 , on the chunk its stamped M A 518 . m a is a truck chunk, splines should be 26/28? any help would be great. also on the pinion gear itself is stamped 3789391-10-39. number on chunk is 3707340 is it car rear truck it is 10 bolt. but wicth one????

It would be helpful to indicate what year, make, and model vehicle you are working on. However, the 10-39 would indicate a 3.90:1 ratio. The most common rear end used on TF trucks such as my 56 have a 10 bolt housing with a 3.90:1 ratio. I'm not sure offhand what number of splines are on the axles.
Fred

thank you rfs56trk for responding. i do have pics of the rea in the project journal under my name.1961 apache 6 banger with 3 on the tree. their are 4 diffent 10 bolt rears i just want to know is it 7.5/7.6/ 8.2/8.6 ? i would like to get a posi for it. now im finding 17 spline is car axle?

I put the year, type and other relevant info for my truck into my signature, where you have “id rather be playing”. This way every post you make has the info we all need to better answer your/our questions.

What you have is what is known as an Eaton "corporate" rear end with the drop out center section. I believe it was referred to as a H033. It was common to 1/2 ton trucks from 55 through 62. There isn't much available except an aftermarket 3.36:1 gear set.
I don't believe there was a posi available for that unit, but if there was it would have been extremely rare. There are many 10 bolt rear ends in both cars and trucks in later models but it's unlikely that any of the internal components interchange.
Fred

Note: The spare axle(s) I have for my 56 have 17 splines.

Clutch type limited slip carrier was an option, at least in later years. Had on 30 + years ago, couldn't find clutches, etc.

thank you all for the info, really helped