Gen3 9.25 axle to replace Gen2 9.25

[russellle]

I have been looking and not found much on this. There is plenty about upgrading from 1/2 ton to 3/4 ton and 1 ton axles from the same generation of trucks. I have a 99 1500 with 9.25 rear axle. I was trying to replace the pinion oil seal and wound up over torquing the pinion nut, causing the crush sleeve to do it's job. After starting to take the rear end apart, I found something I am not sure about. It appears to me that a part of the differential has been riding against the bearing cap and wearing a groove into it. See pics. One shows the protruding metal piece which is loose but will not come out. The other two show the two bearing caps, one with an apparent groove worn into it and the other from the other bearing.

That being said, I am not sure this rear end is worth rebuilding (at least not to me). I was able to buy a 2003 9.25 axle for $300. It has the same gear ratio 3.55 and LSD. It does have disc brakes, which I was planning to convert to in the future anyway.

All that being said, does anyone know of any issues with this installation? I know the yoke on the pinion is different, but I have another drive shaft with the correct connection. I have 16 inch rims with 315/75R16's mounted. Do I need to mess with a proportioning valve at all? I am

 

[98hemi-ram]

I'll be interested to see what you find out with this swap. Somehow I think it will be far from a direct swap. If your other driveshaft is from the newer ram the diff came out of the yoke end that goes into the tranny will also be different and will not work in your trans

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[dodge dude94]

I do believe at a bare minimum the leaf spring perches are further out, closer to the wheels, on the 3rd gen 9.25. I dunno about the pinion though, I think that's the same.

 

[98hemi-ram]

I do believe at a bare minimum the leaf spring perches are further out, closer to the wheels, on the 3rd gen 9.25. I dunno about the pinion though, I think that's the same.

Pinion flanges are definitely different I know this from having the driveshafts out of both my 2nd and 3rd gen ram far more times than ive ever wanted to lol.

 

[dodge dude94]

Pinion flanges are definitely different I know this from having the driveshafts out of both my 2nd and 3rd gen ram far more times than ive ever wanted to lol.

Well there we go. lol


There was a guy on the unmentionable forum that was trying to put one in his 2001 one time and I forgot the outcome of that project.

 

[Merc225hp]

I can tell you this your 16" rims will not clear the rear disc brakes, I know this as I tried to do this upgrade many years ago. The person on the other forum is still working on this swap and he is lacking in info in his thread. As for the pinion yoke take the one off your current 9.25 and install it on the newer 9.25 diff.

The part that is causing the groove is called lsd clutch retaining clips, leave it like that and it will only get worse.

 

[Johnn123]

Merc is right, you're gonna need 17" rims, 16's dont fit 3rd gens. Gonna have to make sure the spring perches are the same, if not have to measure out, knock off and weld on the proper ones. I dont see why the pinion yoke from the old axle wouldnt fit on the newer 9.25.

 

[russellle]

Thank you for the info. That has saved me some headaches. Next question, if I get new rims/tires, is the lug pattern the same from the 99 to the 03? Want to make sure if I get 4 rims that they will work front to rear.

I was anticipating the spring perch issue and am prepared to do the cutting and welding needed.

 

[dodge dude94]

Lug pattern is the same 5x5.5.

 

[Merc225hp]

You can get new spring perches if needed right from Dodge and they are cheap like $12CDN for the pair.

 

[russellle]

*** Update ***

I have removed the old axle. I cut the perches from the new axle and welded them in the correct locations. The perches on the new axle are the same width, just the wrong location, so no need to replace them. The new axle is bolted to the truck. The shock mounts did not need any changes, shocks bolted right up. I installed new rotors and pads.

As I stated originally, I have another drive shaft that has the companion flange connection rather than the u-joint straps. I did a test fit and it is going to work, just going to replace the 2 u-joints and clean it up a bit. As several guys stated, I could have used the pinion yoke from the old axle, but I chose to not have to mess with re-torquing the pinion nut. I know it's not that big of a deal if you take your time and pay attention to what you are doing. Obviously I did not do that the first go around, but if I had not made the mistake, I would not have discovered the impending failure as the differential would have eaten itself apart and left me on the side of the road somewhere.

I am replacing the center rear brake hose with a new 2003 hose since it is longer than the 1999 model by nearly 3 inches. One note here, the 2003 axle uses M10-1.0 brake line fittings and the 1999 is 3/8". So, I will have to get an adapter M10-1.0 to 3/8" to mate up to the existing 3/8" steel brake line fitting on the frame rail. Also, not required but I am going to remake the steel brake lines on the axle because moving the perches moved a bolt that is used to secure the joint from the steel lines to the flexible lines at the wheels.

One item I am still working on is the parking brake cables. I am not sure if the 2003 cables will work or if I am going to have to rig something up to make it work. The 1999 cables use a lead ball/acorn on the end to connect to the parking brake. The 2003 cables use a connector shaped like ~ to connect. I am going to try the 2003 cables. I will update on what I find.

Next I am looking to replace the front wheel studs which are 1/2-20 .620" knurl to a 9/16-18 .620" knurl which is what the 2003 wheel studs are. I want all the wheel studs to be the same all around. Plus heavier duty studs cant hurt.

I will be replacing the wheels (and tires obviously) because as Merc stated, 16" rims will not work (I was not doubting you, just trying to be detailed in my post). 17" and 20" are the two OEM sizes for Gen 3 trucks, but I am leaning towards 18"x9" wheels with some LT325/65R18s.

So, for all to know, this is not just a simple bolt up replacement, but not impossible or extremely difficult either. It is possible and if you are planning to change wheels/tires and go larger than stock and looking at possibly converting to rear disc brakes this is another possible alternative. I will get a few pictures uploaded next week.

 

[98hemi-ram]

Good job man glad to see this working out for you. If I could find a 3rd gen axle I'd be tempted to try this before installing my gears in my current axle. Took me several weeks and a nearly 5 hour round trip to finally find the 3rd gen axle for my 06 last year lol.

I would love to have disc in the rear to though.

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[BeauDuke01]

what about the speed sensor in the rear end? are they the same plugs? or did you swap them?

 

[russellle]

what about the speed sensor in the rear end? are they the same plugs? or did you swap them?

It's the same plug. Just connected the old connector to the sensor on the new axle.

 

[leadrofthepak]

Awesome write up man! I will definitely keep this in mind if I ever get notion to do 4-wheel disc on my 2nd gen.

 

[BeauDuke01]

Outstinkinstanding