I believe my '66 E225 has Posi, it has the tag on the rear diff, althought I haven't tested it yeto No: If it is, I'm wondering what ratio it is? Thanks!
If it's the same lineup as 1967, it's standard w/ 2.78:1, with 3.07:1, 3.42:1, 3.91:1 optional. Other than pulling the differential cover off for inspection, the only way to figure it out would be to attach a tachometer and let us know the engine rpm at a specific steady speed. Devon
If your the axle tube isn't rusted too badly, take some light sand paper or wire brush and look at the bottom of tube on the driver side 3-6" away from the differential housing. Really, it could be anywhere in between the diff housing and shock mount. The stamped codes for PT axle are as follows: 2.78 PO 3.07 PV 3.23 PZ 3.42 PW On posi's there will also be an X with a circle around it near the code.
Or, jack up the back of the car, put it in neutral (block wheels), put a mark on the tire and a mark on the drive shaft. Have someone slowly rotate the tire one complete revolution while you count drive shaft revolutions. The number of revolutions corresponds to your ratio. For example, just under 3 1/2 revolutions is 3.42, 3 1/4 revolutions is 3.23, etc. If you aren't sure between two ratios, perform the above, but rotate the tire two or more times while counting driveshaft revolutions. Divide the total number of driveshaft revolutions by the number of times the tire is rotated. This should give you more accuracy. Hope this helps!
I think they'll be fine (sitting in a box in the basement at the moment). I'm running a 3.07:1 posi right now. Devon
I have a 3.42 and a 3.23 rear sitting at my house not yet installed, that's why I was asking. I'm planning on the 3.42's with tall tires if need be for long road trips.. (sorry for the minor thread hijack, Alex)
So I guess I'll throw my coveralls on, jack her up in the back this afternoon, and do a little rear end inspection.:laugh:
She's a dirty girl. SO she makes me wear coveralls. Still haven't done my wire brushing/sandpaper:spank: I will tomorrow when I get her up on the hoist at school
The stamps sometimes are nice and deep but other times they are so light they are tough to see no matter what. Typically I have been able to find and identify the code on all but severly scale rusted axles. Once you locate part of the stamp if it isn't quite readable sometimes if you take some chalk and rub over the area, then lightly rub it off the high spots, the stamp will appear more noticeable.
Put her up in the air, no luck. Guess I'll be counting teeth :grin: My shop teacher made a point to remark how much faster she went down on the hoist than up...:rant:
Put her back up, rotate the tire and count driveshaft revolutions. Simple to do and you don't need to pop the cover. And to test if the posi is working, simply powerbrake it! :3gears:
