How hard would it be to put a 9'' in my 91 f150 would it just bolt in or would i have to modify anything. I appreciate any help.

 

just curious, but why would you want to swap a 9" in?

 

yes it will swap right in. you can even use the rear brake hardware (shoes,springs) from your 8.8 on the 9". you will lose your rear abs but frankly it doesnt make any difference. I did this swap about 2yrs ago and has been great other then the abs light on. braking is fine.

 

Hopefully this isn't considered threadjacking but on my 94 I was told I can't do the swap because there is some sensor in the pumpkin that controls the E4OD trans. Is this correct?

 

That's correct. If your 1991 F-150 has an E4OD, you also cannot do this swap. The VSS in the rear axle controls the rear ABS and the E4OD until 1992. Then it controls the speedo as well.

 

91 & 92's can swap to a 9" with no affects. the e4od signal comes from the tcase. its 93 that those signals come from the rear diff vss.

 

What about the driveshaft length....?

 

I was considering this swap a few weeks ago ... what would be the best donor vehicle to get the 9" from ..... so that spring perches and shock mounts would be in the correct place ... or will those need to be moved around on any 9" we use?

 

If you're all considering the swap for strength reasons - it's not really much if anything for an upgrade. The 8.8 is a good axle.

 

for my 88 the stock driveshaft worked just fine. i did the swap because i was a couple hundred miles from home and the 9" was $100. i do like the idea that if i break an axle in my 9" the wheel wont fall off. the cost to upgrade both axles is about the same.

 

Well ... since the yoke was rather loose on the pinion ... I expect problems down the road, and the 9" is tougher than the 8.8".

Kem Burns .... what did you get the 9" out of .... was it from an earlier year 150 .... a Crown Vicky .... a Real Mustang like my 73, which is not with me, that I have a spare 9 inch and locker for?

 

Are you sure? What about in a 2wd truck?

 

Yeah, that's another problem with the 8.8" axle. The pinion nut likes to back off on you. I've had it happen before.

If you take it out of anything other than a truck, you have to be careful of two things. One is the bolt pattern. Only trucks have the 5 x 5.5" bolt pattern. There are also a few early 80's F-100's with 5 x 5" wheels. Be careful. The second thing is the spline count. Most trucks have (I believe) 31 spline axles and most cars have (again, I think - Kem or someone else will know for sure) have 28 spline axles.

If you have a locker out of a 73 mustang, chances are it won't fit in a truck 9".

 

if your going for reasons of toughness...the 9" is still in the end a 1/2 ton axle. if you want to "step up" go with a dana 60. like said before the 9 isn't much stronger than the 8.8, and seems like a lot of work unless there is something wrong with the axle that is in there right now.

 

Thanks AndyM .... I tightened the pinion nut a few weeks ago .... my trucks ugly sister truck that a guy at the hobby shop on base drives daily had the same problem 3 years ago and the tightened it then, I hope mine is as good.

I know the 9 is 1/2 ton, I really wouldn't want to put the bigger 8 luggers in there ... If I have to replace I would feel better about a 9 than and 8.8 .... just call my a younger old schooler.

With the other engineering nightmares of this truck .... if I want a 3/4 ton or 1 ton I will start looking at buying a 2500 or 3500''s.