I put a 9.75 axle in as part of my drivetrain swap, unfortuneately the new axle is from a 2000 and has the smaller 12mm studs. Also one of the studs is bent, I have been running it as I was still able to torque the lug, BUT I am not comfortable with it. I am going to be running a wheel spacer in the future and the truck will be on 37's so I want to go back to the larger 14mm studs. I know I can drill out the holes for the larger studs...does anyone know what size they are and what size they would need to be drilled out to? I do still have the original 8.8 and I believe the axle tubes are the same size and they use the same brakes, does this mean maybe I can just swap the hubs / backing plate or are the studs in the axle itself? I have never pulled it farther apart than just pulling the rotors so Im not 100% sure what I am dealing with yet. What do you guys think is the easiest way for me to swap the larger 14mm studs? THANKS!

 

im pretty sure the studs are on the axle itself i dont see why you couldnt drill the holes out but the problem with that is you cant drill out to a 14mm hole then your studs wouldnt fit properly get some calipers to measure the hole a machinists handbook wouldnt hurt either or just measure the holes from one with 14mm studs

 

ya took the brakes off the 8.8 I have...the studs are in the axle like I was thinking, so I could either remove the axles, pound out the small studs, drill out the backing plates on the axle and press in the larger 14mm studs BUT I dont know if I am 100% comfortable with that as they would have to be drilled perfectly and probably pressed in so they would be tight enough.

What about just swapping axle shafts with a newer truck or maybe even the axles out of my 8.8 that already has the 14mm studs? anybody know if both axles use the same axle shafts?

 

Pop one of the 12mm studs out of the axle and compare it to a 14mm. You will notice that the splines are the same. That means you can simply replace the 12mm studs with 14mm.

 

really? I bought one of each size from my local napa (actually one came from napa and one came from kragen) BUT the splined area on the larger 14mm stud is def bigger than the 12mm one I bought, the larger one's spline diameter is about 1mm larger using a caliper.

Neither one of the studs I got is probably the same brand ford uses...should I just go buy 10 14mm studs from ford and hope they are the same maybe? JMC you are the man but Im just slightly leery to do it because I basically have to pull the axle apart do it, including $60 worth of fresh fluid.

 

If you are unsure buy one and see if it will fit in your axle. Actually I have a spare axle from a 9.75 with 12mm studs. I will pick up a 14mm and check it out for you. Give me a day to find the 14mm.

 

I already bought one of each size stud, BUT the axle is still in the truck so I dont really have a way to check to see what size the holes in the axle actually are without dumping the fluid, pulling the clips and removing the axles and checking it out, unfortuneately I cant have the truck down right now so I need to figure out if they will swap right out and if so get them ready. If you are willing to give it a shot I would definetly appreciate it! if you are able to try one of the larger studs will you measure the hole in the axle and both studs with a caliper? Thanks JMC!

 

i just swapped a new axle shaft in not long ago. i guess i ended up with a left over rear end because the shaft i got came with 12mm studs and the holes drilled to fit them. the rest of the truck is 14mm.

i was going to swap studs but i remember the 14mm studs would not fit the new axle shaft.

 

any luck JMC? Chieffx4 Im not totally following you...you changed the whole axle or just one axle shaft in your existing axle? Did you actually check the size the the holes the axle and/or the size of the studs or did you assume they didnt fit?

 

i swapped the passenger side shaft only. it was brand new and matched it to the code on the axle.

the new axle shaft came without the studs installed. i pulled a stud from the old shaft (14mm) and tried putting it into the new shaft (drilled for 12mm). it did not fit.

 

bummer...I really had my hopes up it was going to be that easy! Thank you for answering the question for sure though!

 

I would have answered to this sooner, but why dont you just replace the bent 12mm stud and go on about your business? Those 12mm lugs are not going to break with the spacers and 37's. They are plenty strong enough, unless you plan on jumping the truck or something. People have run much larger tires on 8.8 rear ends that also have the smaller lugs. I think that your ring gear will be the weakpoint before the lugs are. If you insist on using the larger studs then find used axle shafts out of a 97-99 9.75 with the 14mm and swap the axle shafts. The 8.8 and 9.75 shafts are different. I believe the ones for the 8.8 are longer.

 

Haha Brad... He actually is planning on jumping it. And if he doesn't I will seeing as that is how and why he is building it the way he is. Haha.

 

haha ya Im not fully caging the truck and spending THOUSANDS to go full kill long travel for nothing, the truck will def be jumped, slammed through deep whoops, and overall driven HARD, desert trucks take a huge beating (probably more so than just about any other driving out there) and Im not even excited about running the spacers at all so I want to make sure I keep it as strong as possible! I tend to like to go overkill rather than what I think will work and hope it doesnt break...honestly I want to go to a full floating fabricated race axle as soon as possible but thats another $2500-5000 depending on what parts you use.

 

Well the news isn't good. I couldn't find a 14mm stud so I went and bought one. Unfortunately the 14mm stud, as you may guess, will not fit in the 12mm hole. The person who told me he did this on his truck is no where to be found. So I owe you an apology for leading you down the wrong path. For that I am truly sorry.