What's involved in doing a 3.73 to 4.10 gear swap?

[tschwab]

Possibly considering having 4. 10's installed to replace my 3. 73 (48RE auto). IF I decide to have this done, is it just the gears that are replaced..... or is their ECM programing/transmission changes that need to be done?



Approximately what kind of cost am I looking at to have this done? Just in the exploratory stages right now. I will have a much better idea if this will become a reality next week when I return from our 1st big tow.



Currently truck is rated at 21K GCWR, 4. 10's spec at 23K GCWR. If I just have the gear set changed, would my truck then spec at 23K?

 

[klenger]

Having a 2WD will make the change a lot less expensive than a 4WD. As to the GCWR, changing out the gears (or any other mods to the truck) will not change any of it's ratings, but personally, I would not worry about GCWR anyway as it is an unpublished number and I don't see any way it can be enforced. Your truck will behave like a truck with 4. 10 gears after the mod, and that's the important thing. Also, it is pretty hard to exceed the GCWR with a SRW pulling a 5th wheel because you will exceed the truck's GVWR because of pin weight long before you exceed the GCWR. I would think that the mod would be worth the expense with an auto transmission and the weight you are pulling.

 

[NDanecker]

Possibly considering having 4. 10's installed to replace my 3. 73 (48RE auto). IF I decide to have this done, is it just the gears that are replaced..... or is their ECM programing/transmission changes that need to be done?

The gears are a basic swap. To get the speedo and ABS to work properly, you'll have to specify the new gear set in the ECM. This is done thru a hand-held scan tool so you'll need to make a trip to the dealer for this. Unless of course you know someone or have the tool yourself!



Looking back, I wish I got the 4. 10s instead of the 3. 73s also. :{



I'm still on the fence for keeping my Dodge or getting a Ford. Seems everytime it breaks down I promise to get rid of the Dodge but get sucked back in when I see how much I'll loose on the trade in. My out the door price for this Dodge was $47k. Trade in is around $26k with 30k miles and about 1 year old. Ouch!!!



If I still have my Dodge by this Fall, I'm planning new gears with ARB lockers all around (if available). I ice fish upstate and need the full locking F/R diffs. The stock limited slip differential that Dodge offers really stinks in the froozen stuff.

 

[JCleary]

The gears are a basic swap. To get the speedo and ABS to work properly, you'll have to specify the new gear set in the ECM. This is done thru a hand-held scan tool so you'll need to make a trip to the dealer for this. Unless of course you know someone or have the tool yourself!



Looking back, I wish I got the 4. 10s instead of the 3. 73s also. :{



I'm still on the fence for keeping my Dodge or getting a Ford. Seems everytime it breaks down I promise to get rid of the Dodge but get sucked back in when I see how much I'll loose on the trade in. My out the door price for this Dodge was $47k. Trade in is around $26k with 30k miles and about 1 year old. Ouch!!!



If I still have my Dodge by this Fall, I'm planning new gears with ARB lockers all around (if available). I ice fish upstate and need the full locking F/R diffs. The stock limited slip differential that Dodge offers really stinks in the froozen stuff.

The pinion factor will only need to be changed if you change tire size. The speed is picked up by the ABS sensors.

 

[klenger]

I don't think that the ECM needs to be reprogrammed for gear changes. As I undertand the system, the speed pickup is on the rear axle, not the drive shaft. The only factor that changes speedo calibration is tire size.

 

[Matt400]

Also consider someone who may have 4. 10's and want your 3. 73's

You could just trade axle assembly.

 

[Tim]

I still can't understand why anybody would want 4. 10 gears in these trucks.

 

[NDanecker]

The pinion factor will only need to be changed if you change tire size. The speed is picked up by the ABS sensors.

#ad
Yep, I believe you are correct! Sorry about that. Looks like I jumped the gun with that post.



For some reason I thought the ABS sensor ring was on the pinion (input) side of the differential. Being on the output side does make sense as the speedo will work if any one of the 3 (front left, front right, rear pinion) ABS sensors are connected. From a design aspect it would make sense to keep the input factor the same for all 3 inputs. I guess what threw me off was the location for the rear ABS sensor. Its on top of the carrier case.



I've done a number of gear changes in my time, but never one with ABS. Something tells me swapping out the stock carrier with a ARB locker will be a pain in the arse on these trucks. But then again... maybe not!

 

[klenger]

Tim:



The reason for the 4. 10's with the auto is to get the RPM's up a bit for towing because of the numerically final drive ratio with the auto. the 48RE with 4. 10's is almost the same gearing as your G56 with 3. 73's. Also, the autos are more susceptable to failure with high loads and low RPM's.



Examples:



Trans - - - Ratio - - -- RPM - - - Speed

G56 - - - - 3. 73 - - - - 2000 - - - -64

48RE - - -- 3. 73 - - - - 2000 - - - -73

48RE - - -- 4. 10 - - - - 2000 - - - - 66



As you can see, the 48Re with 4. 10's is almost the same as your G56 with 3. 73.

 

[catoiler]

I have 4. 10's in mine and would love to trade for 3. 73's

 

[Coolslice]

I still can't understand why anybody would want 4. 10 gears in these trucks.

I thought like that until recently. IMO, if I were to do it all over again I would go with the 4. 10's. The 3. 73's would be ideal if you do alot of high speed interstate driving. I however spend most of my time on 55mph roads. The 4. 10's would have been a much better choice for me in hindsight.

 

[JEly]

I wish I would of gotten the 4:10 as well-------with 315's on and towing my rpms are too low IMO. I did check the price of changing and it was pretty pricey.



JIM