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4.10 gear swap

8K views 21 replies 12 participants last post by  jstatruck 
#1 ·
So, I think I've decided to swap my 4.56s over to 4.10s. Is anything else required for this besides:
1) A set of 4.10 gears
2) Gear Lube/Oil
3) Bottle of friction modifier
4) RTV sealant for the housing cover

Do I need a new carrier or anything like that? From what I've found, the differential cover just uses RTV as a gasket, is this right?
 
#2 ·
Yes you will need a new carrier also. If you are interested I have the factory 4:10 gears and carrier from my truck, they have about 3000 miles on them and are in perfect condition. PM me if you are interested.

Bill.
 
#3 ·
There should be quite a few 4:10s available because many of the '04 guys swapped them out for the 4:56s. It might be wise to check with some of them before you do the swap. Most of them thought the 4:56s were an improvement.
 
#5 ·
Thanks Joe, got two micrometers, digital and analog, I've done two gear swaps before, one on a 1991 GMC Sierra 1500 and the other on a 1984 Vette, but always try to do as much research as I can before I start turning bolts, otherwise I get my a** in a bind pretty quick.....

Anything else that I might be forgetting?
 
#8 ·
BigBlackQC said:
but always try to do as much research as I can before I start turning bolts, otherwise I get my a** in a bind pretty quick.....

Anything else that I might be forgetting?
You're a smart man ;)

I assume if you've done gear swaps before then you have access to bearing pullers and a press? Keep your fingers crossed that the carrier doesn't need to be shimmed or you may need new side carrier bearings. You will also need new pinion bearings, pinion bearing preload shims and pinion depth shims from a 04 rear end. The pinion shaft diameters are different between the 4.56 and 4.10 gear sets.
 
#11 ·
Stingray, yes, bearing puller and a press are two things, among many, that I can't do without when working on cars.... As far as the shims, I'm picking up some various sizes from a local differential/transmission/gear shop so I think I'll be good.....

AWDIsuzu.... yes, better milage and dropping the RPMs on the highway, I can't see turning a 8.3L V10 between 2500 and 3000 rpms on the highway for hours on end.....
 
#12 ·
Getting ready to swap out mine too thats is why i tried that poll early with o5 with power adders I dont think there are alot of 05's racing I have the parts but trying to find the time to do it... It is hard to go with out the truck..
 
#13 ·
BigBlackQC said:
AWDIsuzu.... yes, better milage and dropping the RPMs on the highway, I can't see turning a 8.3L V10 between 2500 and 3000 rpms on the highway for hours on end.....
My '05 RC with 4:56s runs at about 1,700 rpms at 75 mph. :confused:
 
#16 · (Edited)
Big Asp, the auto tranny doesn't have the 6th gear ratio.... if it did then i wouldn't be thinking about this at all.... However, at 80mph it turns right around 2500rpm, with a 4.10 it should be a 10% drop in RPM due to a 10% change in gear ratio, resulting in 2250@80mph, which hopefully will result in a 10% increase in gas milage, or 1.1-1.2mpg.... it's worth a shot for a couple hundred bucks....

$200 divided by $2.50/gallon for gas is 80 gallons. multiply that by 12.1mpg (10% higher than what I get now, 11) and in 968 miles this theoretically will have paid for itself. IMHO I'd say it's worth a shot.

Tom, I thought about the unitrax but just want to see how this pans out first, if all works well then at my next diff. fluid change (about 6-8 months from now) I will swap to the unitrax., I just don't have any traction problems as is.
 
#19 ·
BigBlackQC said:
Big Asp, the auto tranny doesn't have the 6th gear ratio.... if it did then i wouldn't be thinking about this at all.... However, at 80mph it turns right around 2500rpm, with a 4.10 it should be a 10% drop in RPM due to a 10% change in gear ratio, resulting in 2250@80mph, which hopefully will result in a 10% increase in gas milage, or 1.1-1.2mpg.... it's worth a shot for a couple hundred bucks....

$200 divided by $2.50/gallon for gas is 80 gallons. multiply that by 12.1mpg (10% higher than what I get now, 11) and in 968 miles this theoretically will have paid for itself. IMHO I'd say it's worth a shot.

Tom, I thought about the unitrax but just want to see how this pans out first, if all works well then at my next diff. fluid change (about 6-8 months from now) I will swap to the unitrax., I just don't have any traction problems as is.
BigBlackQC

Your numbers are good, but don,t forget to add in the price of the new gears,carrier, lube and a little for your time!! ;)

I personally don't think you will see any difference in gas mileage!! I changed from 4:10 to 4:56's and didn't notice any difference in gas mileage!!

I did notice that the truck was much smoother through the gears!!

Also, I don't believe you will need a new carrier, not 100% sure though, I didn't put in a new carrier for my gear change, just had a good rear end guy do the install.

Good Luck and let us know how it goes!!!
 
#20 ·
Gears+Carrier+Lube=200..... 3,000 miles on the gears and carrier, but that's not too bad and worth a shot... If the gas milage doesn't increase then the 4.56s are going back in!
 
#21 ·
BigBlackQC said:
Gears+Carrier+Lube=200..... 3,000 miles on the gears and carrier, but that's not too bad and worth a shot... If the gas milage doesn't increase then the 4.56s are going back in!
If you can get gears, carrier and lube for 200.00, go for it!! Cause last time I checked, a carrier was going for $600.00. Not trying to burst your bubble but good rear end equipment better cost you more than $200.00. Unless you have a great connection and get things less than cost????? :confused: :confused:
 
#22 ·
Don't want to be a di*k

But it sounds like a waste of time to me. When I put the long tube belangers,catless midpipes and M/F cat back, I picked up approximately1-2 MPG. I think 2,500 at 75 is cool, I used to drive my 340 duster with 4.88's back and forth to school, 70 miles round trip at 3800 rpm, and it was all good. I think these V10's are pretty stout, maybe run 5w-30 instead of the 0w-20, cause thats where the problem could develop if you drive the truck alot, the oil breaks down. I talked to a Pennzoil rep ( I would never use Pennzoil) and he said thru tests they have found oil breaks down in about 1000 miles under normal driving conditions.
My 2 centavos
Zack
 
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