Hi everybody.The rear end in my 78 bronco is shot.I've been told it's a ford 9 inch and that all the 78+79 broncos had 9 inch rear ends that had all the same gear ratios.To help in my search for a used replacement could some of the good folks in hear help me out as whether those 2 things are in fact true.Regards and thanks

 

Hello, they all had 9 inch rearends, but there were different ratios available, I have 2 79's one with 3.5 something, the other had 4.11's. Not to mention that someone along the way could have put something else in too. A 9 inch from most 73-79 1/2 ton trucks will work, watch out though, there are some with different size U joints out there. Assuming your axles are in good shape, why not just change the pumpkin?
Wim

64 F600 Drilling rig
75 F250 4x4
(2) 79 broncos
Too many projects!

 

Oops, forgot, check your spline count. 28 spline small bearing, 31 spline large bearing 3.062 If you have the 31, keep it and fix it!

Wim

 

you can change internals a lot cheaper than getting a whole unit- maybe anyway it's an option- I recently helped my dad get into 4;11 internals for his '79 150 he had 31 spline- definitely keep 31 spline.

 

Thanks for all the help.This might sound stupid to you folks with more experience,but how do you check the ratio on a ford 9 inch.To me it looks like one solid case with the fluid hole.There doesn't look to me to be a case cover to take off and look or can the case be opened.Or do I have to spin the tire and count the revolutions while also watching the drive shaft.Thanks

 

Hey check this out it may help http://www.autozone.com/servlet/UiBr...3d800ce9fa.jsp

 

The older a truck gets, the less reliable the door stickers and axle tags are. Someone easliy could have done exactly what you are doing - swap third members for a different ratio.

The 9" has a removable third member. This means you can relatively quickly install and uninstall pre-setup gears. The whole carrier, ring, pinion, side and spider gears come out as one big unit, aka third member. It unbolts from the front. You'd need to pull the wheels and drums off and slide the axles out far enough so they won't interfere. Drop the driveshaft and unbolt the third member, and the new part goes right in.