D44 spindle size ?? and backing plate ?? too.

[5trucks]

Here are pics of the pass. side spindle and bearing. The axle is from a different vehicle and i wanted to know if i have the smaller of the two d44 parts. Timkin bearing has a number on it. LM501349. Will this affect an 8 lug swap when i get around to doing it? Also, if the spindles are all 6 hole and the backing plates are as well, why do they need to be changed for the swap. Thanks

 

[4X4HIGH]

The outer bearings are all the same. Starting in mid 1976 GM changed the inner bearing to a larger IIRC 2" ID bearing. The same race is used with both the smaller bearing and the larger bearing so no real big deal other than needing to make sure you have the correct bearing for the spindle you're going to use.

The backing plates need to be changed because the 3/4 ton rotors are a slightly larger diameter and the calipers will hit or rub on the rotors if the larger back plates aren't used.

FWIW you do not need to change the spindles when doing a 3/4 ton conversion, only the hub/rotor assembly and the back plates need to be changed.