dodge35000

For the people that have done their own 3rd gen Dodge 2500/3500 gear swap, I am getting ready to change my ring and pinion from 3.73 to 4.56. I wanted to know how long it took to do the front axle and how long it took to do the rear axle?

Also, did you have any problems getting anything apart(ie. pinion gear out of the axle housing, seized unit bearings)?

I am planning on doing the gear swap in my driveway and wanted to know how much time to allocate to it and to make sure that I don't get caught by something unforseen.

BigIron70

Someone who has all the tools and has done it before could take 5 hours or more per axle. Dial indicator, torque wrench, pullers, turning torque meter, are just a few of the tools needed. I would not attempt it unless you have these tools. If bearing preload or backlash isn't set properly you will have noisy gears or pinion bearings will fail if preload isn't set to spec.
Here's procedure, good luck.
ADJUSTMENTS
Ring and pinion gears are supplied as matched sets. Compensation for pinion depth variance is achieved with a select shim, located between the rear pinion bearing and pinion gear head.

PINION DEPTH MEASUREMENT AND ADJUSTMENT
Measurements are taken with pinion bearing cups and pinion bearings installed in the housing. Take measurements with Pinion Gauge Set and Dial Indicator C-3339 (PINION GEAR DEPTH GAUGE TOOLS).

Assemble Pinion Height Block 6739, Pinion Block 8897 and rear pinion bearing onto Screw 6741 (PINION GEAR DEPTH GAUGE TOOLS).
Insert assembled height gauge components, rear bearing and screw into the housing through pinion bearing cups (PINION HEIGHT BLOCK).
Install front pinion bearing and Cone-nut 6740 onto the screw. Tighten cone-nut until Torque To Rotate the screw is 1.7-2.26 N·m (15-20 in. lbs.) (PINION GEAR DEPTH GAUGE TOOLS).
Place Arbor Discs 8289 on Arbor D-115-3 in position in the housing side bearing cradles (GAUGE TOOLS IN HOUSING).
Install differential bearing caps on arbor discs and snug the bearing cap bolts. Then cross tighten cap bolts to 281 N·m (207 ft. lbs.).
NOTE: Arbor should rotate freely in the arbor discs.

Assemble Dial Indicator C-3339 into Scooter Block D-115-2 and secure set screw.
Position Scooter Block/Dial Indicator flush on the pinion height block. Hold scooter block and zero the dial indicator.
Slowly slide the scooter block across the pinion height block over to the arbor (PINION GEAR DEPTH MEASUREMENT). Move the scooter block till dial indicator crests the arbor, then record the highest reading.
Select a shim equal to the dial indicator reading.
Install the select shim between the rear pinion bearing and the pinion gear head.
DIFFERENTIAL CASE BEARING PRELOAD AND GEAR BACKLASH
Backlash is adjusted by moving the adjusters in and out or both. By moving the adjusters the case/ring gear will move closer or further away from the pinion. In most cases this adjustment can be used to achieve the correct gear tooth pattern and set the case bearing preload.

Remove adjuster lock bolts and adjuster locks (ADJUSTER LOCK BOLT).
Loosen the differential bearing caps.
Slide differential case toward the pinion gear until the gears make contact/zero backlash. If zero backlash cannot be obtained, turn the pinion side adjuster until zero backlash is obtained.
Holding the differential case toward the pinion gear, turn bearing adjusters with Spanner Wrench 8883 (ADJUSTER SPANNER WRENCH) until they make contact with the differential bearings/cups.
Back off the ring gear side adjuster 4 holes, to obtain initial ring gear backlash.
Install ring gear side adjuster lock and bolt. Do not tighten adjuster lock bolt at this time.
Tighten pinion gear side adjuster firmly against the differential case bearing cup.
Rotate the pinion several times to seat the deferential bearings.
Loosen pinion gear side adjuster until it is no longer in contact with the bearing cup, then tighten it until it makes contact.
Tighten pinion gear side adjuster an additional:
New Bearings: 6 Adjuster Holes
Original Bearings: 4 Adjuster Holes
Install pinion gear side adjuster lock and bolt. Do not tighten adjuster lock bolt at this time.
Tighten bearing cap bolts to 115 N·m (85 ft. lbs.).
Tighten adjuster lock bolts to 33 N·m (24 ft. lbs.).
Measure ring gear backlash with a Dial Indicator C-3339 and Dial Indicator Stud L-4438 at eight points around the drive side of the ring gear (RING GEAR BACKLASH). The backlash should be 0.08-0.25 mm (0.003-0.010 in) with a preferred backlash of 0.13-0.18 mm (0.005-0.007 in).
NOTE: Backlash measurement should not vary more than 0.05 mm (0.002 in) between measuring points. If measurement does vary inspect the gears for burrs, the differential case flange and ring gear mounting.

GEAR TOOTH CONTACT PATTERN
Gear tooth contact pattern is used to verify the correct running position of the ring and pinion gears. This will produce low noise and long gear life. Gears which are not positioned properly may be noisy and have shorten gear life.

Wipe clean each tooth of the ring gear.
Apply gear marking compound to all of the ring gear teeth.
Verify bearing cap bolts are torque specification.
Apply parking brakes lightly to create at 14 N·m (10 ft. lbs.) pinion rotating torque.
Rotate the pinion/pinion yoke 4 full revolutions in each directions.
Read gear tooth contact pattern:
Gear contact pattern correct (CORRECT CONTACT PATTERN). Backlash and pinion depth is correct.
Ring gear too far away from pinion gear (INCORRECT BACKLASH). Decrease backlash, by moving the ring closer to the pinion gear using the adjusters.
Ring gear too close to pinion gear (INCORRECT BACKLASH). Increase backlash, by moving the ring away from the pinion gear using the adjusters.
Ring gear too far away from pinion gear (INCORRECT BACKLASH). Decrease backlash, by moving the ring closer to the pinion gear using the adjusters.
Ring gear too close to pinion gear (INCORRECT BACKLASH). Increase backlash, by moving the ring away from the pinion gear using the adjusters.
Pinion gear is set too low (LOW PINION HEIGHT). Increase pinion gear height, by increasing the pinion depth shim thickness.
Pinion gear is set too high (HIGH PINION HEIGHT). Decrease pinion depth, by decreasing the pinion depth shim thickness.

dozer12216

In other words, it is not recomended for a driveway project. 4.56 is pretty extreme for a diesel due to lower RPM potential. Are you pulling a heavy trailer or wanting to use for pulls?????

dodge35000

Actually, I have all of the tools that you mentioned and some. The directions are from the Dodge Service Manual which I have reviewed a few times. I do just about all of the work on my vehicles, so I am comfortable with this job.

My main concern is doing the job in a driveway because the vehicle could be exposed to the weather if I do not finish on time.

I am changing my gears from 3.73 to 4.56 because I just installed 37" tires. Thanks in advance for any advice you can give.

NDanecker

I've done a few gears in my time and I've only done 1 in a driveway and won't do that again. Setting up gears is NOT something you want to do outdoors where wind can whip up dirt and debri up into the axle. Also, you want to take your time with something like this. You may run into problems (tear a seal, parts not fitting, etc.) and having to have this done by dark (or other) just puts unnecessary pressure on the job. Just my opinion.

Can you at least pull the back end into a friends garage or someplace else where you'd be out of the elements? The last two gear swaps I've done was with a lift and WOW....what a difference then laying on the ground! Probably cut my time down in half.

Good luck!

dodge35000

Thank you for the advice. There is a garage I have acess to, but my truck will not fully fit into it. Maybe I can fit one end in at a time. Since it is a small one car garage, I hope that I can get by without having to completely remove the axleshafts.

C Schomer

I only pulled the axles out about 6" when I did mine - just enough to clear the carrier brgs. Craig

dodge35000

C Schomer I had a couple of questions about your gear swap if you don't mind answering them.

Did you have trouble getting anything apart when you did your gears? Did your factory shims work or did it take a few tries to get a good pattern? Last, how long did it take to do each axle?

Thanks again for any advice.

BigIron70

You will need a press to remove pinion bearing to get old shim out. You will want to use this shim if new ring and pinion has a "0" as a variance number. If there is a + subtrack that amount from old shim. If there is a - before the number you have to add that amount to a old shim.

therabbittree

456 gears just for 37 tires?.. 355s or the stock 373s would turn the 37s fine with the diesel... thats kinda a big ratio change..

welndmn

I setup lot and lots of gear sets for many people, and for your first time, I would not start with the dodge. Do you have the speical tool for adjusting the carrier bearing preload right?

If you do tackle this, do the front first. The front's are more forgiving if you give it a poor patteren. Plan on a full day, to do one axle. I have done hundreds, and it still takes me 4-5 hours.

dodge35000

On both the 9.25 AAM front axle and the 11.5 AAM rear axle it has adjusters for the carrier bearing preload and backlash adjustments. I do have the tool to make these adjustments.

My main concern is this a job that can be done in a driveway or would you only recommend that it be done indoors? Also, do you find in many cases the factory pinion shim brings you close to the correct pinion depth and correct contact pattern?

mrdrinksalil

I am very interested in your gear swap. I want to do the same soon. I am on 37s well and occasionaly pull 10-12K lbs. It is real tough getting started though some of that is probably the stock TC. RPMs just drop too low when in 4th and I am seeing egts up to 1350. What kind of unloaded mileage are you getting with the 3.73s? I'm curious what it goes to with the 4.56's. I'm not sold yet on 456s and am thinking maybe 4.11s because I am unloaded driving around 35 highway miles to work every day. I dont think you'll have too much trouble with the gear swap. Its more trial and error than difficult.

WhiteMule

I wound up and had to pull my rear back apart in an RV park in Colorado this summer due to a mistake that I had made during the initial ring and pinion change. I changed the pinion bearings and seal in a grassy area in front of my RV. I will agree that doing this inside a garage would have been better but since that was not an option, I did what I had to. I had to borrow, rent and buy the tools needed to do this as I was on vacation.
So, though not optimal, it can be done in your driveway (rear at least) depending upon your abilities. My advice if you decide to do this, is to get someone to help you as this will involve some heavy lifting (especially on your back). It always helps to have an extra set of hands. Would be better if one or both have some experience in doing this. Allow yourself plenty of time so that your not in a rush. I jacked mine up, pulled the rear tires, removed the center caps, reinstalled tires and put it back on the ground. With the lift and tires, there was plenty of room to work under there. The front would be a different story.