4:10's vs 3:73's
 

OK...so i am learning as i go. Turns out my truck has 4:10 gears instead of 3:73's. I was told when i bought it that it had 3:73's, oh well buyer beware I guess.
So my question is, what kind of cruise rpm can i expect with the 4:10 vs the 3:73? lets say at 70 mph.
Also, what decrease in fuel economy is there with the 4:10 ratio?
Kinda bummed out about this,Somebody tell me that 4:10's are great!!![:'(][:'(][:'(]

RE: 4:10's vs 3:73's
 

4:10's are great for off the line performance as well as pulling and towing, however you shouldn't expect this thing to be so great top end. The 4:10s will kill your fuel mileage too. They will pull down the side of a mountain when paired to the right motor too.

RE: 4:10's vs 3:73's
 

a 410 has 1 purpose..to PULL...forget performance/mpg

RE: 4:10's vs 3:73's
 

What year is your truck? I just wanna find out if you have a 3speed (TH350) or a 4 speed (4L60) or a manual.When I had my 04 crew cab Z71 (four speed) (4.10's) I could run 75mph at about 2400rpm's.

I averaged 16mpg on the highway on a 1300 mile trip between Ohio and Wyoming(I was hauling a longblock 355,two 12" wide tires and rims, two 6" wide tires and rims, and half a bed full of toys from my sons first birthday party.)

RE: 4:10's vs 3:73's
 

Nate's pretty much on the mark. I have 4.10's with 6.0 3/4 ton 4x4 and I'm usually around 2300 to 2500 (I've got a few hills in my area) and last time I took it out on the interstate I got around 13-14 mpg. I just put a TBS on and I can tell a big difference in my throttle response and it seems like I'm getting better milage, but I'm not sure. I'm heading to Kansas this weekend so I'll know what I'm getting with the TBS and I'll let you know. I'll probably do the throttle body bypass after I go to Kansas......

RE: 4:10's vs 3:73's
 

I forgot to mention that if you're going to be pulling anything heavy on a regular or semi-regular basis - don't swap out the back end. Argon's right, as usual, you can pull all day with 4.10's and a good motor. I've got the 4speed auto on mine and I pulled the bigger track hoe that Bobcat makes up a hill from a dead stop - kept up with traffic and the pedal wasn't ever near the floor.

RE: 4:10's vs 3:73's
 

My truck has the 4l60e auto 4spd. I came across a formula once where you can figure out rpm given a certain gear ratio and tire size. So as Nate says,if 4:10's give you about 2400rpm at 75mph what would the 3:73's spin the motor at given the same speed?

RE: 4:10's vs 3:73's
 

Im not sure about the 3:73 but the 3:42 which is what my z-71 1500 has at 75mph the rpm is at about 2000 to 2100 rpm. If this helps any. Thanks

RE: 4:10's vs 3:73's
 

the 342 is gone...it was about the perfect balance rear end...

RE: 4:10's vs 3:73's
 

What was the last year for the 3:42?

RE: 4:10's vs 3:73's
 

just came back from a quick trip and my rpm at 75mph was about 2200 to about 2250, sounds a little low for 4:10's doesn't it?

RE: 4:10's vs 3:73's
 

05...I think

RE: 4:10's vs 3:73's
 

Wade that may be right since your is a 1500. I know superddd has a 2500 so his may run a little high rpms with a 4:10.

RE: 4:10's vs 3:73's
 

i have the 07 clasic...4.10's and at 75 i am am almost exactly on 2500 RPM.

RE: 4:10's vs 3:73's
 

I'll check my 07 classic 373 in the morning

RE: 4:10's vs 3:73's
 

is gearing not just gearing regardless of the size of the truck? If a truck is bigger/heavier would it not just require more fuel/air/horsepower to move a certain mass? unless of course the transmissions are different, then that would effect engine rpm.

RE: 4:10's vs 3:73's
 

Its just like a bike...on speed 5,its ,more powerful but takes more energy.

The general...and all carmakers...go to EXTREMES to find the right "balance"..believe me,if pouring some snake-oil in the crankcase,or moving the timing a fraction would benefit BOTH performance and economy,it would be done

RE: 4:10's vs 3:73's
 

would it be possible that my truck has 3:73's even though it is option coded with 4:10's?(like i said before, guy i bought the truck from swore it was a 3:73 axle)my rpm at 75mph seems to be closer to the 3:73 range than the 4:10 . out of curiosity i jacked up the rear wheels today and did the old driveshaft to tire spin, and it took approx 4.5 turns of the driveshaft to = 1 complete tire rotation. this is more in line with the 4:10's.
I checked my speedometer with my GPS today, and my rpm with my scanner and all are right on the money. My tire size is correct, the reading is same as before: 75MPH=2200 2250 rpm.

RE: 4:10's vs 3:73's
 

I double checked mine and I hit right at 2500 going 75. The weight difference may have something to do with it: your's being a half ton and mine being a three quarter. I don't know what size you're motor is, but mine is the 6.0. Other than having a TBS, everything is stock from the rear end to the tires.

RE: 4:10's vs 3:73's
 

sorry guy's, i guess i should add that to my signature........my truck is a 2000 Z71 Silverado 1500
engine is the 5.3 Vortec, pretty much stock with the exception of a True Flow drop in air cleaner.

RE: 4:10's vs 3:73's
 

07 classic,373..

dead on 2000 @70mph

RE: 4:10's vs 3:73's
 

hey Argon, what do you mean with this?
the 342 is gone...it was about the perfect balance rear end...
cause mine has the 3.42 and im planning on getting 3.73 or 4.10, do you think that would help my performance? whats the better one?

RE: 4:10's vs 3:73's
 

yes,a 342 is no longer available on a new p/u..

remember...all a 410 is for is to PULL...forget performance and mpg...its to pull a load up a hill.

get the 373 for a decent "all around" ratio

RE: 4:10's vs 3:73's
 

thanks so much Argon, do you know about a good torque converter to get?
what do you think about FAST-FLASH programmer? i think it does a very good job in performance.

RE: 4:10's vs 3:73's
 

I'm a gm tech..not much of a performance guy..

SC CHEVYLOVER should be able to fill you in....SC?

RE: 4:10's vs 3:73's
 

Felix, I did some research for you and it apprears that the Fast-flash tune is the same as any other hand held tuner, i.e. Superchips, Hypertech, Jet Performance, etc... You can expect 18hp/17ft-lb and that is it. It is also a little expensive, over 400 dollars. The one interesting thing I found is that the Fast-flash tune allows you to tune your engine if you install a performance cam. I would check out the custom tunes before buying a hand held. There are some guys on here that can hook you up with the custom tunes, because I'm not to familiar with them. Here is the website to Flash-fast if you want to do some research.
http://www.fuelairspark.com/Products...ammer/over.asp

Now, if you are going to do minor modifications and not swap out heads or cam, then your torque converter will be fine. However, if you are going to do major modifications, go with a bigger torque converter. I personally like the TCI 4L60E Super Street Fighter TC with a 3000 stall speed. I will post a link for you so you can do some research on that as well. I'm still doing my homework on torque converters for our trucks, but I'll keep in touch. Hope this helps ya out.
http://www.lmperformance.com/4171/27.html

RE: 4:10's vs 3:73's
 

SC thanks a lot for your info, in a post i did before, someone told me that 3000 stall converter would be a little high, im planning on getting a cam also, and switching my 3.42 for a 3.73 as ive been told to do, they say 3.73 would help my performance, i already have the FAST FLASH programmer, and i think it does a very nice job, my programmer gives me 3 cam options, i dont know whats the best one to get cause i dont know about cams, i will really appreciate your help with that decision, if you cant find my cam options with fast flash and you know about that, tell me and ill send you the cams options.
thanks a lot.

RE: 4:10's vs 3:73's
 

comp cams can help you with the cam. But I would wait till you do other upgrades as this will change the cam you want. Do all the boltons first, then heads, then cam. SC_CHEVY is good at finding good prices and is a good resource, and has helped me so he is a good source.

RE: 4:10's vs 3:73's
 

Smoke, i already did all the bolt ons upgrades, whats next to that? SC?

RE: 4:10's vs 3:73's
 

Another bolt on you can do is the 80mm Throttle Body. BBK is the way to go with throttle bodies. They claim they add 15-20hp and with all you current mods, it should really help out. Here is a link to the BBK throttle bodies.

http://www.performancecenter.com/pro...Lightduty/5.3L

What I would do next is heads/cam, or even possibly greater displacement. Bore to 6.0 or such. There is only (so much) power we can produce out of our motors before you have to replace or upgrade parts, heads especially. If I had the money, I would get a supercharger right now. Therefore, I reccomend the same. If you want to be fast and I mean fast, get a supercharger.

Bottom line to increasing horsepower cost money. How much are you willing to spend is the question you have to ask yourself. Good luck

RE: 4:10's vs 3:73's
 

Supercharger if you can afford it, heads then cam if not.

RE: 4:10's vs 3:73's
 

smoke and SC thanks, i cant afford supercharger, ill get throttle body as soon as i can, i guess ill order it tonight. lmperformance is a good website to get it... i would like to know a good cam and heads setup, if some of you know of a link i can get them, let me know please. or another bolt on?

RE: 4:10's vs 3:73's
 

felix, man all i have done is reasearch heads and cams on our trucks...the BEST thing to do, which is good for almost 100 horsies...is get a good port and polish of tyhe stock 5.3 heads...these heads are AMAZING once they are opened up...ask guys on LS1TECH...they sqap ls1 heads for our 5.3 heads that are ported and polished..and dont have to pay as much as a set of new heads......as for cams, there are several options out there....just depends on how extreme your going to go. me personally, i am going to have it done soon, tired of waiting and saving. but i am ready for it. you can also talk to ISKY cams techs, and they can build a custom grind cam for you...a bit pricey ...but in the end it will all work out.

RE: 4:10's vs 3:73's
 

BigTexasChevy,thanks a lot for your advice, i would like toknow more aboutwhat you are talking about, i mean, port and polish my heads, sounds very interesting...
:D

RE: 4:10's vs 3:73's
 

I wish someone would polish MY head;)

RE: 4:10's vs 3:73's
 

Call blowtie, I'm sure he can take care of that.

RE: 4:10's vs 3:73's
 

the thing to do is find a shop that has done work on GEN 3 and 4 gm motors, and has done headwork...then find out if they will port or polish your heads up. if no one around you will get it done, you can send your heads to several companies that will do it, just google them up.! you'll find someone that will do it.

I'm driving a 2001 GMC Sierra 4x4, 4dr EC, 3/4 Ton, 4 speed auto..I do alot of fifth wheel towing and I too am interested in the 4:10 rears..I know that with the 3:73 at 70-75mph I show an rpm reading at 2000-2200 rpms.

I should also note my truck is fully stock, no mods whatsoever and running the 6.0 Vortec.