I posted this in the clutch, transmission ,etc. forum with 11 views and no answers... I have a 2003 super duty with the 5.4 and 33" tires and a 4.10 rear, would switching to a 4.30 anti-slip setup increase the performance of the truck? anyone running a 4.30 on a 5.4? and since my setup has been the same since the truck was new (over 100k miles), would it have any adverse effect on my transmission or engine (the swap, I mean) thx in advance for any help I can get. and how would my fuel economy suffer?

 

I wouldn't do it unless I wanted the LS diff in the 4.10. Worse gas mileage. No effect on engine, trans, except engine will wear out sooner due to more RPMs per mile. More torque at a given vehicle speed but at a price. Maybe if towing was a top priority. Not a wide ratio difference but I might do it just for the limited slip diff.

 

An opinion: The 4:30 over the 4:10 will give slightly better acceleration. Not only initially, but also when passing another vehicle. The limited slip is of no effect unless in/on slippery road conditions. The 4:30 will be easier on the motor and trans due to the increased torque multiplication. Fuel mileage will vary, depending on ones driving habits. You will get less mileage with full throttle starts, but you will enjoy the acceleration.

Bottom line: "IF" you want good fuel mileage, in fact super fuel mileage, take the bus...

 

So I wouldn't feel a considerable gain in acceleration and rear-wheel horsepower? So what I'm saying is, when climbing steep hills at highway or close to highway speeds, would my truck still downshift or would I really notice considerable performance?

 

4:30's will get you back to stock with 33 tires...No big deal..The diff? Go with a aftermarket Ls diff like truetrac...Stay away from stock..


Dick

 

are lockers truly that bad for non off-road use? I mean I live in northern New Jersey and lately have been doing most of my driving on pavement. (the economy has decreased my trips to northern Pennsylvania)

 

Not really bad but a TT will work fine. If you don't need traction stay with what you have..


Dick

 

Some more power, less downshifting, and some more gas, not that much difference.

 

Is your truck 4X4? If yes, then you'll need to install new gears front and rear. What have you done in the way of aftermarket performance parts such as CAI kit, tuner, exhaust?

 

had the hypertech programmer on high octane setting, considerable gains, but the higher cost of 93 octane had me go back to OEM settings. Have a K&N air filter and flowmaster super 44 dual outlet muffler.

 

I went from a 3.73 to a 4.30 in mine at about 95,000 miles. I noticed a "considerable" difference, especially on the initial "git up and go". Pulling my boat (about 4,000 pounds) it really did nice. Very little downshifting. With my travel trailer (about 5500 pounds and a big wall in the front!), at highway speeds it made a little difference, but not enough to write home about. With any significant hill or overpass it still downshifted (out of overdrive). On the flatland of I-10 it did pretty well. But for the most part, I still locked out overdrive when pulling anything. At 70mph I run at about 2200 - 2300 RPM, where with the 3.73's I was doing around 1900. As for gas mileage, very little difference running day to day. Even pulling my toys is very little difference. It's hard to get an accurate reading of the gas mileage when towing as conditions are always different (different terrain, different road conditions, different weather (headwinds or not)).

Sooooo, what does all the above mean...it depends on how much you are willing to spend going from a 4.10 to a 4.30. Again, I went from a 3.73 to a 4.30. I only paid $400 for a complete rear end, and another $400 or so to get it installed (and 4 new Bilstein shocks since they had the truck in the air anyway!). I think going from a 4.10 to a 4.30 would net you very little in the end, and it might not justify the cost.

 

Not enough ratio difference.

 

Selecting the right gears is like selecting the right wife... you can marry a pretty woman or you can marry an ugly woman... it's going to cost you just as much when you marry them, or God forbid, if you divorce them.

 

Installing the appropriate gears is a more permanent solution to an engine's improved performance and efficiency. I think that the initial cost scares some people away but let's look at some simple mathematics.

You can purchase a quality tuner for approximately $400.00 and use the performance tune that requires 93 octane fuel. The difference between 89 octane fuel and 93 octane fuel is generally 20 cents per gallon. If you completely fill your 38 gallon tank per week, that's an additional "premium" cost of $7.60. On an annual basis, that's an additional "premium" cost of $395.20. Some people may find that a performance tune and 93 octane fuel provides the missing performance that they need.

You can install new gears to ensure that your truck's engine is operating in the power band. The cost of gears varies depending on the size but let's say the average cost of gears is $255.00 per axle (This was the actual average cost of 4.10 and higher Yukon gears at BroncoGraveYard.com). That's a total cost of $510.00 for a 4x4 truck. I would estimate that the labor and misc. parts for the install are approximately $600.00 per axle. So, we are looking at $1,710.00 for new gears installed.

Now let's compare the two options. If I can accomplish the desired results with new gears, then the breakeven point is in 3.3 years. That's taking the $1,710.00 gear cost minus the $400.00 tuner cost, which equals $1,310.00. I then divide the $1,310.00 by the "premium" cost of $395.20 per year, which gives me 3.31 years.

So, if you plan to keep your truck more than 3 years, it actually is cheaper to install new gears than to use a performance tune and 93 octane fuel. Obviously, if you use less fuel per year, the longer the breakeven point.

 

not to mention the reduced strain on ur engine and tranny... Gears is always the best bet, sometiems its just hard to pull the trigger and git ur done...