Yesterday I went to the Junk Yard and got a 3.00 3rd member to replace the 3.70 in my uni.Never gave a thought about spline count till I got it home...You guessed It... the uni is a 28 and the other one is a 31. I had a '78 F150 lb w/ 302 and swapped w a '72(2.75 to 3.50 r&p)no problems.The donor truck w/the 3.00 had a 360 and a 3 on the tree.it was a '73/74.I guess the FE engine made the difference.Anyway does anyone have some 28 spline spiders they care to part with?I could take them out of my 3.70 chunk but I am going to put it back in when I put the AOD in the truck,and don't want to do a bunch of swapping stuff around.Thanks.
Dave
You can swap spider gears and it will work but it isn't recommended because the axle rides in the hole in the housing under load and the hole is bigger on a 31 spline housing so the spider gears take all of the load which they are not supposed to do. In a light car it may not be an issue but in a truck it is a big deal and you will cause excessive wear in the center section if you just change the spider gears. You need a differential housing made for 28 spline gears. BTW, 73-79 Ford truck 9 inch centers are 31 spline as are most but not all vans from the same time frame. Hawkrod
Dave.
Might be one down here you could "borrow" Drop me a PM and I'll ask around.
But I have to ask why you're not going to a smaller ratio. The difference between a 3.70 and a 3.50 isn't enough for all that aggravation.
Uncle Skipper
I'm not arguing with you. I'm just explaining why I'm right.
Pardon me. Does your deaug bite?
I had a '78 F150 lb w/ 302 and swapped w a '72(2.75 to 3.50 r&p)no problems.The donor truck w/the 3.00 had a 360 and a 3 on the tree.it was a '73/74.I guess the FE engine made the difference.Anyway does anyone have some 28 spline spiders they care to part with?I could take them out of my 3.70 chunk but I am going to put it back in when I put the AOD in the truck,and don't want to do a bunch of swapping stuff around.Thanks.
