rear end yoke

[71badblue]

i bought a custom one piece driveshaft and i have a th400 with a fixed yoke so i bought the drive shaft with the slip spline in it. well when the driveshaft shop told me to measure for u joints my buddy measured the yoke on my tranny and we came up with it was the 1350 series. he said the rear end yoke ws the same. so i ordered a 1350 series driveshaft . front went right on yesterday in 3 mins. i go to put back in and it aint even clos. i measured it and i came up with its a 1310 series in the rear. i know they make u joint adapters but could i just put a 1350 yoke in the rear end? or to do that would i have to change axles?