Can I swap a 9" into my 1987? Its an F150 (see sig) that I have been building for awhile now, and the rear 8.8 just went out. I would like to put a 9 inch in it, as they're tough as hell, but I need to know two things.

One, do/did they ever come with a 3.55 gear ratio? I looked on Randys Ring and Pinion and they sold a set of 3.50s but not the 3.55s that I have now.....If I found one with a 3.50 ratio, could I run that with my 3.55 front end and not have problems since they're that close?

Two, I've heard about not being able to ditch the 8.8 because of the speed sensor on top of the housing, but knowing the off road world, and how popular the 9 inch is, someone has had to have found something to fix that. I dont have CC, but this is a daily driver.

Thanks all

 

The slight difference in ratios will not have a negative affect on anything.You will be fine.
In a recent Bronco SAS and upgrade rear axle, I used a relocation kit from Brea auto electric and it works like a champ.
Might give these guys a ring and discuss this.

About Brea Auto Electric: Products: Speed Sensor

 

other than that, is it a pretty much bolt-in swap (i.e shock mounts, brake cables, etc?)

 

Yep bolt in other than speed sensor. As long as you have the right yoke on it for yor driveshaft.

 

Much depends on which vehicle you got the 9 inch out of. For the most part the perches, and shock mounts are easilly changed. Be prepared for the possibility of a driveshaft modification, since the 9 incher may have a diffferent yoke than the other axle. Maybe, maybe not, this could go wither way.
As far as the brake cables, you may have a length difference, and you may end up with a different size fitting for the brake line. All of the above items are pretty easy to modify and should not be a show stopper, but finding some small parts on a sunday might be frusterating.

 

well, there is the whole thing where I have to find the axle too.......this dang thing couldnt have broken at a worse time....my dad is not in good shape and making daily trips to the hospital, i've been out of work for awhile now, being a student. I am supposed to start fighting fire again for the summer, but the dispatch point is at home 200 miles away, and I'm broke. I'm trying to find one, but none of the local yards have one (of course) and since I have absolutely 0 cash to put towards one, it makes it that much harder. I need to go talk to one more guy out at the last yard, but he wont be back until monday, and the lease on the house is up on friday.........all I gotta say is ugh....I know it'll all work out, but it hurts when its happening.....

Sorry 'bout the rant, and thanks for the info...Im looking hard right now, so is there anything I need to look over real well before I go get a rear end from a JY? Last thing big I got from one was a tranny, and it wasnt until I took it to have it looked over that I found it was full of water :P

If I do need another yoke, how hard is it to swap them? Just a zap off and zap on with an impact gun?

Also, found out that the sender on top isnt a VSS, its something for the rear ABS (which has never worked anyways......) so I'm going to see what I can do with that to make it work.

 

You really would. Notr need anything for that sensor. Just leave it unhooked. I think the f150s had 9s in them up to at least 84. So if you got one from a 80 to84 it should be the closest to bolt in. And yes a yoke swap is easy. Take a nut off pop the yokke off and put new one on.

 

deal....I pick it up tomorrow and should have it in by thursday evening

 

I guess you must have found one, best of luck to ya puttin it in, make sure you open it up first and add new fluid...or atleast I would.

 

actually the JY that I got it from already did it for me......they took apart the first one that they were going to give me, but it had shiny stuff in the fluid and the carrier bearings were completely gone, and the ring and pinion were all pitted, so they're taking another one out, and I pick that up tomorrow morning.....they already took it apart in-the-truck and checked everything out and then put new fluid in it....I went and looked at it and it did look good.

best (and worst) part of the whole thing is that with the whole not-having-money thing he took a trade for a shell of a truck that I had bought for parts and tore apart a couple years ago straight across for the axle.....yeah hes getting the better end of the deal here, but I'm getting what I need and am glad I can do it now.......thanks for the help, if you think of anything extra let me know, otherwise I'll hopefully be letting you guys know that the swap went well tomorrow.....fingers crossed!

 

Ok, so I got 'er all done today.....didn't get the axle even until yesterday at 4 o clock because they were shorthanded at the JY, but to make it up to me, they gave me refurbed drums, new brakes and brake hardware, and put it all on for me. Got the 8.8 out and the 9 in, and its nice. Its also a lot lighter (in weight) of an axle, as I could easily pick up the 9 inch by myself, but the 8.8 required a li'l help. But, I got it all back on and it works great, thanks for all the help guys!!!

 

Pics man, we want to see this.

Good job with the install. Now save up a couple of bucks and read some of my stuff on
a $99.00 disc brake upgrade.

 

ill try to get some tomorrow for you guys