K1500 8.25 to 9.25 swap

[Gobistro00]

So to all that have told me it cant be done" In your Face! Lol thanks for sharing, I'm in the process of this as well, from my measurements I don't feel that I'm going to have quite as many issues, I have 6" lift - pro comp? I shaved a peace off frame on driver side because the 92.5 is fatter, but it looks like whoever originally put the lift on the truck shave the fins on the driver side of the 8.25 diff for it to fit, I didn't want to do anything to weaken it, I'll send a photo of what I did if I can figure out how, my donors from a 2004 2500 HD, I wish it was angled on the passenger side mount because I'd be In Like Flint, remind me to remind appears that it's going to bolt in if I altered that bracket hanging down for the passenger side. We'll see, my question for you is, what about the actuator? I've ls 4l80e swapped Holley wiring, can't find a cable actuated for it, need to figure that part out before I carry on ,I haven't done anything thiats keeping me from going back or sas if I win the lottery. Thanks

Sorry for late reply, I used the stock actuator that came with the diff, everything engages fine, used my front lockers about a dozen times too and have had 0 issues, no signs of wear anywhere

 

[offroadtahoe]

to convert to a 9.25 on a stock or cranked 3" lift truck

I'm sure you can use a diff drop kit and modify it,I tried it but you would have to shave the side fins a little bit,and it just hangs too low since its already bigger.i didn't like this route,It drops it 2"

I have a k3500 and k1500 stuffed the 8.25 in the k3500 to check the differences.
The only difference is the driver side top.everything else is the same,tried both,the lower one is the one to use and change the other,for cv spindle to not hit frame/ lca bolt

the bolt in passenger side a-arms stay the same for their frame,

to fit the 9.25 in the stock location.
#1 cut the drivers lower side mounting tab,you need to replicate the stock but make a bolt in version,or you wont be able to get it in

#2 you need to grind the corner of the drivers motor mount frame,not by much can't even tell but the middle of the diff won't clear you and won't be able to get the rear lower bolt in.

#3 the A-arm bolt's that hold the diff need to be drilled to the next size of the 9.25 bolts then use the 8.25 bolts now its wide enough and will bolt up.

#4 the top driver side is going to have to be custom made,check the pics.

 

[spooledyou08]

to convert to a 9.25 on a stock or cranked 3" lift truck

I'm sure you can use a diff drop kit and modify it,I tried it but you would have to shave the side fins a little bit,and it just hangs too low since its already bigger.i didn't like this route,It drops it 2"

I have a k3500 and k1500 stuffed the 8.25 in the k3500 to check the differences.
The only difference is the driver side top.everything else is the same,tried both,the lower one is the one to use and change the other,for cv spindle to not hit frame/ lca bolt

the bolt in passenger side a-arms stay the same for their frame,

to fit the 9.25 in the stock location.
#1 cut the drivers lower side mounting tab,you need to replicate the stock but make a bolt in version,or you wont be able to get it in

#2 you need to grind the corner of the drivers motor mount frame,not by much can't even tell but the middle of the diff won't clear you and won't be able to get the rear lower bolt in.

#3 the A-arm bolt's that hold the diff need to be drilled to the next size of the 9.25 bolts then use the 8.25 bolts now its wide enough and will bolt up.

#4 the top driver side is going to have to be custom made,check the pics.

Sorry if I missed the info, but what cv axles would you use if it was stock or cranked? And are you saying a lift kit makes it more difficult due to the CV axle length because of the differential drop?

This is a swap I’m very interested in if I can retain the 1/2 ton hubs and bolt pattern.

Thanks for the info!

 

[offroadtahoe]

sorry i should have added,i made my own thread with the cv axle info and updated pics. https://www.gmt400.com/threads/9-25-ifs-conversion-0-3-lift.60583/#post-1284970

for stock or cranked 0-3" the stock 9.25 cv's fit
keeps 6 lug.

yes it does,after testing my stock 9.25 cv setup i can see how,lift kits where your cranked 6" and not true 6" diff dropped,if you decrank you wouldn't have to shorten your cv axles,

LCA's in a straight postion with 9.25 cv's have plenty of space.the second you start cranking the lower control arms come down,at a point you instantly start losing space,
now imagine the cranking going a few inches more then stock 0-3"..even .5 past the 3" mark its diff drop,this is why you will have to shorten axles.

 

[spooledyou08]

sorry i should have added,i made my own thread with the cv axle info and updated pics. https://www.gmt400.com/threads/9-25-ifs-conversion-0-3-lift.60583/#post-1284970

for stock or cranked 0-3" the stock 9.25 cv's fit
keeps 6 lug.

yes it does,after testing my stock 9.25 cv setup i can see how,lift kits where your cranked 6" and not true 6" diff dropped,if you decrank you wouldn't have to shorten your cv axles,

LCA's in a straight postion with 9.25 cv's have plenty of space.the second you start cranking the lower control arms come down,at a point you instantly start losing space,
now imagine the cranking going a few inches more then stock 0-3"..even .5 past the 3" mark its diff drop,this is why you will have to shorten axles.

Thanks for the info. Does the 9.25 differential require front drive shaft modifications due to its size difference, or are the yoke to transfer case distance the same?

 

[Supercharged111]

Thanks for the info. Does the 9.25 differential require front drive shaft modifications due to its size difference, or are the yoke to transfer case distance the same?

OP will have the for sure answer, but I think the yoke hangs farther back. Pairing this with a 4L80 swap negates the need to modify your front driveshaft for the additional length of the 4L80. I think.

 

[offroadtahoe]

Thanks for the info. Does the 9.25 differential require front drive shaft modifications due to its size difference, or are the yoke to transfer case distance the same?

if you have the collapse kind,it should push in enough to get the driveshaft in,if not it has to be shortened