9 inch ford swaps
 

I have ford nine inch 3.70 ratio in my 58 ranchero but they show lots of wear especially on pnion teeth so now I also have a 9 inch 3.25s out of a 65 ford f 100 and looks really good shape problem is there is no filler plug on that case and my housing under my 58 doesnt have a filler plug on the back the ring gear and pinions are different thicknes so I ask can i change the 3.25 gears with its own carrier or do i have to just trade the ring gear and of course the correct pinion match??

Re: 9 inch ford swaps
 

My last 2 projects had the same situation.
I TIG welded a 1/8 pipe plug on the rear of the housing and on the bottom.

Re: 9 inch ford swaps
 

You can swap out the pumpkin providing the axles have the same number of teeth.

Re: 9 inch ford swaps
 

You can pour the correct amount of lube down the axle tube if you jack it up on one side. You will be ok unless you have a leak.

Re: 9 inch ford swaps
 

I had the same issue with a 57 Ranchwagon. Took out the 3.89 and put in a 3.00. I drilled a hole on the flat just right of the pinion support, tapped it with 3/8 pipe. There is room to put it the same height as the original fill hole. Just need to be careful when tightening the new plug. Thread sealer is your friend here. No leaks after 5K plus miles. Still leak free when it was sold.