How difficult to do?

[69rangerman]

I've got a good running 302 in a 69 f100 and have it at about 15mpg but wouldn't mind trading some efficiency for a little more torque. It's got 3.25 gears now/want 3.50 and I was wondering if this kind of swap was within the range of a novice. No fear of pulling axles etc. but seems like I've read warnings about setting up the gears correctly? It has a 9" diff.

Thanks for any advice

[fordman]

are you just wanting to change the ring and pinion or the whole third member. swapping the third member is just a part replacement operation. setting the lash and stuff is a little more involved. i read about it once but i've never done it.

[tynall44]

if your taking the 350s out of a old housing take everything and just gut the housing in the truck and put all the 350 stuff back in shimms and all..... then put yellow or white paint on the ring gear spin it and look where the pinion hits it , if its anywhere near the middle of the ring gear it will be fine i used to swap em all the time on my round track cars

[oldschoolrods]

I have done a few heavy truck diffs here at college and they are similar to the 9 inch, there not too difficult but arent just a simple parts replacement, best thing i can advise is get yourself a book, I can tell you you will need a pinion depth gauge and a magnetic base dial indicator.

[67highboy]

Having a pinion depth gauge is nice but not totally nesecary IMO, indicator and mag base are though.
I would recomend using a book and take your time.
Its not rocket science but it is critical to make sure the wear pattern is centered, the preload on the pinion bearings are set correctly, and the backlash is set correctly.
But if you take your time and be thourough you can do it.

John

[69rangerman]

Sounds like one of those "wait til I've done research and don't need the truck for a week" jobs. Thanks for the tips-at least I have a starting point.

Have a great holiday!

Thanks again,
Tom

[foghorn]

I just did a pumkin change and its a easy swap. I found a whole rear end from a late 70 to a early 80's cougar bought it for $100 and swapped it out. this rearend even had the hat like bill on the yoke housing and my yoke still cleared it with ease. The only prob i had was getting the yoke off of my pumkin. When you go back in with it use a good anti seize on the splines. I don't think mine had ever been off since it came out from the factory. I did put a new yoke seal and used a little RTV along with the o-ring on the housing. The axel seals were still in excellent shape so i didn't replace them and so far no leaks. Its been almost a week now and no sign of them leaking at this point. Just put the truck up on stands. Yank the wheels drums and unbolt the axels and slide out about 4". Unbolt the drive shaft and the pumkin and replace. Go back with the replacment then reinstall till you have it back on all fours. Then your done.