I am currently having my second 8.8 rearend rebuilt in my 83 F150. The first one was replaced with a used unit out of an 89 F150. Are these axles known for being problematic? The unit that is being rebuilt now came out of a low milage truck and within 10,000 miles of being installed in my truck started having problems. Then the other day the pinion bearings started squeling. Mechanic told me if I'm lucky he'll only have to replace the pinion bearings and races, if I'm unlucky I'll need gears also. I'd like to upgrade to a 9" rear, but my front axle is 3.07 gears and I don't think the 9" rears came with gears close enough to that ratio to work properly. Hopefully someone will prove me wrong.

 

How can one tell if he has an 8.8 or whatever rearend? I have an 83 f150 with 3.55 gears and have had to replace mine twice . I know mine has the bearings that use the axle as a race.

I am pretty sure the first was due to getting water in it when launching a boat. But within about 30k miles it went out again. This time it started with a bad wheel bearing which wore down the axle .........all the hardened steel mixed in with the gear oil took the facing off the gears.....the result was a complete melt down.

I had been hauling a camper which was pretty big......close to 2000lb I asked my mechanic if that was the cause.......he said that the rig should handle it but I bought a lighter camper (1500lb) anyway. I am hoping it handles this better.

I don't know if this is helpful to you. Or even if we have the same rear end. I will be following this topic closely though.

 

The main advantage of the 9" ford is the removable center section which makes gear changes easy. It does not make the total load capacity any greater. That is a function of the axle tube size/thickness, outer wheel bearings and to a certain extent, the wheel lugs. (alxe capacity, not spring, tire or frame capacity)

Ford does not recommend slide in campers on the F150. That said, I have one on my 86 f150 and have had no problems, but mine is very light, about 1100 lbs.

In my case, my 6200 GVW f150 (4x4, Supercab) has a base weight of 4700 lbs, so it has a capacity of 1500 lbs (this does not take into account the front / rear weight bias and how that might affect each end's individual capacities), so if you add this up, people/gear ---> 200 to 750, nominal say 350 lbs, and the camper at 1100 lbs, that alone makes it 1450 lbs, so you can see that not much is left over for all of your misc camping gear and other things we carry along.

OVERLOAD comes to mind. I was mindful that the 8.8" in my F150 also has almost 170k miles in it.. so I chose my camper carefully, we will see in the long run how things hold up.

No wonder I see so many people on the side of the road with failed rear axles.
It is hard to blame the 8.8" or 9" axle for our own mistakes??

Just my two cents...

 

An 8.8 axle will have a diff cover that bolts on the back. The 9" has the 3rd member that bolts on to the front.

You might check some yards, the 9" was in a lot of the early(80-83) F-150's and broncos, figure out the door tag code you need for 3:07 gears and go looking.

I had an 83 F-100 with the 8.8 and only had to replace the outer bearings and seals at about 100k miles, after my father filled it with compost and made it bottom out, even with add-a-leafs, coil helpers and airshocks. My 95 F-150 with the 8.8 never had a problem in the 130k I put on it, and I pulled some big trailers with that truck.

 

My 83 F100 is having problems at 160000 miles on it. It is an 8.8 3.55 ratio. Instead of messing with it I'm looking for a 9" to put in it.

 

lectricman, why was the first one replaced? You will want to check out the rest of your drive train, an unbalanced drive shaft, bad tranny mount, tranny output shaft, etc.. can put a lot of stress on the pinion and cause damage to the rear end. The 8.8 is a very good rear end and not problematic at all. The 9" is a good rear end as well, and is a little tougher.

 

The reason I replaced the first one is because it had so much slop in it that it was unbearable to drive. You literally had to be very careful how you shifted gears and let out the clutch. I just got my truck back today, the crush collar that sets the tension on the pinion bearings evidently was completely crushed and ate up the front pinion bearing and oil slinger. So it wasn't as bad as I originally thought. Now that you mention it, I wonder about my driveshaft. I might look into getting it balanced. Thanks for the info.

 

Who ever setup the second rear end set the pinion bearing preload up to tight got hot ate the bearings. You can get 308 gears for a ford 9 inch and that would work. The 8.8 is a good rear end, just a pain in the butt to set up right. I do not know what the load rating is for either rear end but I do know that a stock 31 spline axle 9 inch is rated to withstand 1200 hp's. That is the reason they race with them. For people that are going to load there trucks heavy I would recommend using a 75-140w synthetic gear lube in these it will supply needed lubrication even at very high temperatures and this is what Ford recommends on the new rear axles from 7.7 - 10.75. Also a lot of people use 80-90w gear oil in there rear ends and this isn't right stuff look at the owners manual and they will all list a xx - 140w for rear gears.

 

Still, that's not confuse the load carring capability of a axle with its twisting (torgue loading) capability.

By my research, while the 9" is certainly stronger in the twistng strength (1200 hp), in the load carring capability it has nothing over the 8.8" (about 3800 lbs, give or take)

On a truck the load carring capacity is the one that means the most, at least if the truck is used as it was intended (load carring) and I agree that whomever setup that 8.8" didn't do the job right.

 

the other thing is did you have an l.s. rear? clutch noise sometimes can be pretty loud in the rears.

 

The 8.8 rearend has never given me any problems and I treat it severely bad. Pulling 12,000lbs behind the truck for a 100 miles straight, you dare not touch it it'll scold your hand. Then there's all the droppin the clutch and the bad wheel hop it has, especially when you get it going in reverse and drop it in 2nd. Before i got the truck my uncle used to haul cattle all the time with it with a 18x7 gooseneck and now I use it for hauling my tractors to tractor pulls on a 25ft gooseneck flatbed, i just dropped the original oil out of it about 5,000 miles ago and rebuilt the engine 1000 miles ago. (86 F-150 4x4, 4spd, 300-6, 275,000miles) had an original clutch, I replaced it, but it really wasn't that bad, if I ever get around to it I'll put in different tranny fuild, also original, I pulled the input shaft bearing to check it when the engine was out, that smell would knock you on the floor, wheeeeeewwww, lol, but anyways my rearend hasn't even blew the wheel bearing seals yet, also due to that I caught the vent hole being plugged up which shot fluid out the input seal, but once I unplugged it it was alright.

 

The only thing that was wrong with the 8.8 in my 84 F150 was it had 3.08 gears with an open diff. Since then I have installed 4.10 gears and a locker...much better set up for my needs. It has given me zero problems, I haven't been exactly nice to it. Mud bogging, trail riding, pulling stumps, big trailers, pulling other stuck vehicles, hole shots, burnouts, you know anything like that, that could leave drive train parts and gear lube on the pavement or trail. It's a plenty stout axle for what I do.