4Running Daily
Connor
- Joined
- Oct 3, 2018
- Messages
- 288
- Age
- 27
This is an idea I've talked with my friend David Farmer about many a time. If you design a 4WD LT kit, your limiting factor will be CV's for travel. And even most aftermarket kits just use Tundra CV's which aren't that much stronger than the tripod inner. Replace those with $1k RCV's, and you'll blow the diff first. Probably good for 16"-18" of travel with Tundra RCV's and my 3.5" LT. But you still have that 7.5" front diff. So if you're a guy who likes having 4WD for sand, but is primarily a go-fast build, this thread isn't for you.
But for the rest of us that like the complexity of IFS and want an upgrade up front, I think it's time we come up with a solution.
So I started digging around on the internet and found the famous AAM 9.25. This is your IFS diff for 2500 trucks. Here is a compatibility chart:
PDF is attached to the end in case you can't read this.
Ok so continuing on, this is a 1 ton IFS diff with a 9.25" ring gear. All aftermarket ratios are available for it, as well as lockers like an ARB. But it needs to be center mounted.
Also it's a big fucking diff
As you can see, it's a driver diff offset. Which is already ideal for our setup, but I want center mount front diff, and equal length CV's.
I don't see any clear reason, without buying one, as to why you couldn't take a gasket, scan it, DXF, and laser cut it. Then machine a cup for the bearing, and plate your own side of the housing more or less so that the stub shaft from the driver side fit in the passenger side. Then you would have the perfect mating surface for 2 CV's.
This is all theoretical until I try it.
Obviously there are cons with this diff. The stock 7.5" diff without an extension tube is 44 pounds. This 9.25 is 100-125 pounds. But it is weight that is theoretically below the center of gravity at least. It's also fucking massive. Obviously it needs extensive modification before it can even be attempted to be mounted, and I have no idea how you would get it in there without raising the engine and possibly even a new/modified oil pan.
Someone will ask about hubs too, but I purposely designed my LT kit to work with a fully fab'd spindle without modification. So really just a hub selection, then measure for axles and send them off to RCV.
Notable links to 9.25 info:
https://www.dieselworldmag.com/gm/u...5-aam-front-axle-for-your-gm-or-dodge-part-2/
https://www.race-dezert.com/forum/threads/center-mount-aam-9-25-front-differential.126163/
https://www.pavementsucks.com/threads/aam-925-axle-specs.39358/
https://www.gmfullsize.com/threads/...ton-locked-aam-9-25-with-hydro-assist.215119/
Other diffs to consider:
Ford 8.8. They are super cheap ($250), and have slightly less aftermarket ability.
The case doesn't split though, so I don't know how you would be center mount it. Notable mention though.
And also the 9" from the 2nd and 3rd generation Tundra's. These seem cool, lots of aftermarket, you can't find a diff for shit though. You'll never see one in a junkyard, and the only one on eBay is $800. It's been proven that you can shorten the ADD tube. The case also splits, so theoretically it could work.
Other options considered:
IRS diffs. Supra, Mustang, anything big and common would be great. But low pinion diffs up front seem to be not strong and not a good idea.
Aftermarket options:
Currie F9 https://www.currieenterprises.com/CE-4305B ($5k with gears and an ARB)
Dynatrac ProRock XD60 https://www.dynatrac.com/prorock-xd60-ifs.html ($6k with gears and an ARB)
Haven't looked into the Dana 44 front diff. If it can be center mounted, it is an option as well.
But for the rest of us that like the complexity of IFS and want an upgrade up front, I think it's time we come up with a solution.
So I started digging around on the internet and found the famous AAM 9.25. This is your IFS diff for 2500 trucks. Here is a compatibility chart:
PDF is attached to the end in case you can't read this.
Ok so continuing on, this is a 1 ton IFS diff with a 9.25" ring gear. All aftermarket ratios are available for it, as well as lockers like an ARB. But it needs to be center mounted.
Also it's a big fucking diff
As you can see, it's a driver diff offset. Which is already ideal for our setup, but I want center mount front diff, and equal length CV's.
I don't see any clear reason, without buying one, as to why you couldn't take a gasket, scan it, DXF, and laser cut it. Then machine a cup for the bearing, and plate your own side of the housing more or less so that the stub shaft from the driver side fit in the passenger side. Then you would have the perfect mating surface for 2 CV's.
This is all theoretical until I try it.
Obviously there are cons with this diff. The stock 7.5" diff without an extension tube is 44 pounds. This 9.25 is 100-125 pounds. But it is weight that is theoretically below the center of gravity at least. It's also fucking massive. Obviously it needs extensive modification before it can even be attempted to be mounted, and I have no idea how you would get it in there without raising the engine and possibly even a new/modified oil pan.
Someone will ask about hubs too, but I purposely designed my LT kit to work with a fully fab'd spindle without modification. So really just a hub selection, then measure for axles and send them off to RCV.
Notable links to 9.25 info:
https://www.dieselworldmag.com/gm/u...5-aam-front-axle-for-your-gm-or-dodge-part-2/
https://www.race-dezert.com/forum/threads/center-mount-aam-9-25-front-differential.126163/
https://www.pavementsucks.com/threads/aam-925-axle-specs.39358/
https://www.gmfullsize.com/threads/...ton-locked-aam-9-25-with-hydro-assist.215119/
Other diffs to consider:
Ford 8.8. They are super cheap ($250), and have slightly less aftermarket ability.
The case doesn't split though, so I don't know how you would be center mount it. Notable mention though.
And also the 9" from the 2nd and 3rd generation Tundra's. These seem cool, lots of aftermarket, you can't find a diff for shit though. You'll never see one in a junkyard, and the only one on eBay is $800. It's been proven that you can shorten the ADD tube. The case also splits, so theoretically it could work.
Other options considered:
IRS diffs. Supra, Mustang, anything big and common would be great. But low pinion diffs up front seem to be not strong and not a good idea.
Aftermarket options:
Currie F9 https://www.currieenterprises.com/CE-4305B ($5k with gears and an ARB)
Dynatrac ProRock XD60 https://www.dynatrac.com/prorock-xd60-ifs.html ($6k with gears and an ARB)
Haven't looked into the Dana 44 front diff. If it can be center mounted, it is an option as well.