Changing 4.10s to 3.73s ?

[MojaveJoe]

How hard would it be to change the rear diff from 4.10 to 3.73 gearing?

And how much for parts and to have a dealer do the swap? I know, Im sitting down for this number.

Looking at a 2006 5.9/ 600/ 3500 SLT Bighorn with 4.10 gears. Comes with a 3mo/3000 mile drive train warranty. So if I can change the rear diff gearing (like I had) I would feel good about the overall towing ability and relative fuel economy when not towing (90% of the time).

Any and all input appreciated.

 

[RVTRKN]

Auto? Manual, stay with 4:10 it's easier on the Trans. Auto, might as well be a good idea to stay with 4:10's. Look at my 07 C&C in sig, wish I ordered it with 4:10s.

 

[MojaveJoe]

If I didn't drive it much I'd consider the 4.10s for the towing pluses. At almost 20K per year, most w/o towing, I can't see running the higher RPMs on the hwy.
Yes, an auto. My last 48RE was rebuilt to eliminate the common failures, and shifted quick like it was ready to put some more torque to those rear tires, not like it was afraid of them. :-laf
I wish I still had that trans to put in my next truck.

If I buy the truck with 4.10s I will drive it until Iam unhappy with it. Just wondering if the swap is feasible, how costly, and if it will require an ECM update? Anything else I may have missed?

 

[RVTRKN]

To technical for my limited knowledge, as far as price, I'm sure your looking @$1500.00 min. If your not towing, 3:73 are ideal for your style. Just not sure of the difference between auto and manual characteristics, I want 4:10s. You close to SoCal? Maybe we can do a swap?

 

[MojaveJoe]

I imagine you are right about the price. But if I do it, gotta be a professional job. Don't want to be servicing the rear end every 3 years.
Yes Im in SoCal. As for a swap, I don't have the truck yet, but if i get one with 4.10s I will PM you someday about it.

 

[RVTRKN]

Cool, good to hear

 

[mpaulson]

No ECM changes. The speedometer counts the number of ring gear revolutions and the rate of pulses from the sensor in the rear differential which will be the same no matter what gear ratio you put in. I did a change from 3.73's to 4.56 in my last 07.5 truck, nothing to do computer wise on these truck for a gear change.

 

[MMeier]

Joe, give Adams Driveshaft up here in Henderson Nv. a call, if you don't mind the short drive. Pretty sure he will do gear swaps. Adams (702)568-5680

 

[Tuesdak]

A dealer is the LAST place you want a diff done. You need an experienced shop that knows what they are doing to get them set properly. Usually they are exclusive to doing rear ends. Next door to the shop I told you about does rear ends as well as Performance Transmission in El Mirage, AZ. New gears and bearings... 4x4 takes both differentials doubling your cost.

Consider a good rear locker while you are there as we know the anti spin factory setup isn't very strong. Like a Yukon Grizzly or old school Eaton Detroit. Survey says MT trucks appear to be friendlier with a True Trac limited slip (over a locker) with more bias than the factory stuff has.

 

[MarkEkberg]

If you smart you can do it. I did a set years back. Took my time, had to change the shims to get the correct grease pattern on the gears.

Just need a dial indicator and specs.

 

[lpennock]

Why not just post an add on your local craigslist for someone to swap axles with you. People that are running 37+ tires would be interested in the 4.10 axles and the swap is pretty quick.

 

[MojaveJoe]

Wow Guys...That's a bunch of good info....... thanks. Yes I certainly will lookup a specialty shop then. Dealers rarely do such work, now that I think about it.

Did I read that right. If I have a 4.10 rear end, the front diff is also 4.10? And I would need to change both diffs, at twice the price? Good reason for me to buy a truck with 3.73s or 3.42s then
Now sure I would ever need anything other than the Limited Slip diff. I rarley do an serious off-roading/no-roading, but I have had situations in snow/mud where the free wheel would spin in back , until I engaged the 4wd (if I recall clearly)?

 

[lpennock]

Did I read that right. If I have a 4.10 rear end, the front diff is also 4.10? And I would need to change both diffs, at twice the price? Good reason for me to buy a truck with 3.73s or 3.42s then
Now sure I would ever need anything other than the Limited Slip diff. I rarley do an serious off-roading/no-roading, but I have had situations in snow/mud where the free wheel would spin in back , until I engaged the 4wd (if I recall clearly)?

You read it right. Front and rear need ot match.

 

[inlinesix3million]

A lot of folks prefer the 410's. Should not be a problem trading for what you want- even steven. I like my 410's just fine when not towing. I run 34" tires and get 18-20 mpg.

 

[Mingoglia]

Front and rear need to match if you use 4wd. If you want to have a smaller kick in the pants, and can live without 4wd for a while you can do just the rear, then save some coin for a few months then get the front done. Truck will drive just fine. Now if you put it in 4wd, well, magic things will happen.

 

[MarkEkberg]

Now if you put it in 4wd, well, magic things will happen.

Black magic.