Full Size Jeep Network

Hey everybody.

Title says it all. I picked up an absolute peach of a 1989 J10 (Laredo package no less) with a 360. Automatic. Interior is mint. I want to drive this thing and with that I also want to do some preventative maintenance.

The factory Dana 44 and AMC 20 will be fine for around town and around the farm, but, after doing a dynatrac swap on my 2023 gladiator, I have a set of new Rubicon Dana 44 axles with no home.

Looks like the length of the J10 axles are about 63/64", and the rubicon axles should net me roughly 5" overall (2.5-3" on both sides).

My idea list is as follows:
-Cut brackets off new axles
-Weld new brackets for springs, etc.
-Get some different backspacing wheels to tuck into the wheel wells (assuming I can find some skinny wheels/tires)
-More lift if I do run into backspacing issues
-New driveshafts. Guy that does mine is pretty flexible but I'm not sure if he can make the original t-case work. I hear flanges have changed over the years.
-Maybe an ARB compressor/lockers down the road since wiring the factory electronic lockers sounds like a nightmare, especially on this old truck.
-I think the clearances for the factory axles will be similar to the new Dana 44s in terms of fuel tank/underbody room.

I think it's a cool idea, but with that usually comes lots of roadblocks but I was wondering if anybody here has done something similar. Of course all the cool, new, fully built J10 builds/mods with new products don't ever post their how-to's online.

Biggest concerns are getting wheels/tires. I feel like the backspacing necessary might be impossible to find. If I can, I will have very little up travel before I hit the fenders if those wheels do poke out. Factory JT wheels might be a good place to start. Although, since I'm full-time 4WD right now, those caps for the hubs make me wonder if the new Dana 44s won't be about that wide. I'm thinking the new wheel mounting face will be towards the end of those center caps as it currently sits.

Let me know what you think! Thanks.

This says there's no such thing as an '89 J10. https://en.wikipedia.org/wiki/Jeep_Gladiator_(SJ)
What's the VIN?

A J-truck Corporate model 20 is not the same as the CJ model 20. Not a bad axle. IMO what you are suggesting is not an upgrade; instead a sideways move.

The rear axle on a J-Truck should be roughly 66.5" WMS as I recall. The rear axle is actually wider than the front. Nothing narrower will work unless either link the rear axle, or move the springs under the frame.

As I recall a JL Rubicon rear axle is 66.5" WMS. So, they might fit. But its possible the calipers will hit the springs. As the J-Truck rear axle has drums that are narrower than the disc/e-brake setup on a JL axle.

The front Could be an issue if you are wanting to keep your truck the same height. Up front, the axle is a spring under, and I think the pumpkin is going to be in the way of where the spring wants to live. You might have to outboard the springs, which is something people do if using super duty axles.

But as noted above, the M23 (FSJ version of the M20) is stronger than D44's of the era. Not as strong as JL Rubicon rear D44, but its not a giant difference.

tgreese wrote: ↑Fri Feb 02, 2024 8:06 am A J-truck Corporate model 20 is not the same as the CJ model 20. Not a bad axle. IMO what you are suggesting is not an upgrade; instead a sideways move.

The JL uses AdvanTEK "D44" axles. They are a D44 in name only, and not comparable to the D44's that came on FSJs (no parts interchange). The internals are quite a bit stronger than older D44s.

tgreese wrote: ↑Fri Feb 02, 2024 8:06 am This says there's no such thing as an '89 J10. https://en.wikipedia.org/wiki/Jeep_Gladiator_(SJ)
What's the VIN?

A J-truck Corporate model 20 is not the same as the CJ model 20. Not a bad axle. IMO what you are suggesting is not an upgrade; instead a sideways move.

Yes, the J-trucks ran until '87 and left over '87's were sold as '88's--I have an '87. Regarding the late model Jeep axles, they all have the smaller 5x 5" bolt pattern and seem a little light for a Full size truck. However, if you have a free set and can weld in the brackets to make it fit under the FSJ springs--go for it. Or maybe adapt the frame to use the Wrangler coils and 4 links.

Possible this is an MJ? DId they come with the Laredo graphics?

Other than the 5.5 bolt pattern, everything is beefier on the newer axles

^^^^^^couldn't agree more. This was a serious consideration on my truck before I crawled down the path I chose. The wheel studs are 14mm vs 1/2” so even that is debatable about the bolt pattern.

rocklaurence wrote: ↑Sat Feb 03, 2024 12:42 pm Regarding the late model Jeep axles, they all have the smaller 5x 5" bolt pattern and seem a little light for a Full size truck.

Its the same wheel stud size and pattern that the Ram 1500 uses. They can haul and tow more than any 1/2 ton J-Truck was able to, so that would not be an issue.

I think the main issue is are the axles going to clear the springs, as I noted above.

Stuka, FYI Dodge 1500 are 5x5.5 for the Classic and 6x5.5 for the updated fancy model. 1000% correct on the towing and hauling, even more than all but the heaviest GVW J trucks, but not by much.

Yeller wrote: ↑Sat Feb 03, 2024 3:47 pm Stuka, FYI Dodge 1500 are 5x5.5 for the Classic and 6x5.5 for the updated fancy model. 1000% correct on the towing and hauling, even more than all but the heaviest GVW J trucks, but not by much.

Oh, you are right, it is 5x5.5. Either way, the 14mm studs are more than strong enough for an FSJ. The axles will be a weak point before the wheel studs are.

Exactly

Stuka wrote: ↑Sat Feb 03, 2024 3:31 pm

rocklaurence wrote: ↑Sat Feb 03, 2024 12:42 pm Regarding the late model Jeep axles, they all have the smaller 5x 5" bolt pattern and seem a little light for a Full size truck.

Its the same wheel stud size and pattern that the Ram 1500 uses. They can haul and tow more than any 1/2 ton J-Truck was able to, so that would not be an issue.

I think the main issue is are the axles going to clear the springs, as I noted above.

Thanks for pointing out the similarities