p3ripperfw

Been doing some research on gearing after I put my 33's on my truck and it is lacking.....have 3.73's with limited slip in my fx4 and the gearing chart says 4.10 would be right near stock.....Problem I have is it says the chart is done for a 5 spd manual trany and that if you have an auto Od trany that the rpms will be lower.....

So I was pretty much set on putting 4.56's in but when I called 4wheelparts to ask them about the gear sets they carried I was transfered to their "driveline" tech. When I told him I had 33's and the 5.4L and wanted to put 4.56's in he pretty much might as well have said "hey you idiot what are you thinking" and I couldnt even get my question in because he was going off on how that would be a 20% change and way too much and cause me a loss in my mpg and all this....problem is even though I want my truck to get better mpg...(getting 12 now) I dont want to lose the ability to tow....Im running 1800 rpms right now at 65-70 and if when I need to pass the truck is downshifting way too easy. Havent towed with it yet but know its going to be lugged down pretty bad.

The guy at 4wheel parts is saying id be crazy to go anything above 4.10 but Im thinking that the chart does not take into account the Od gearing so there could be some leway.....

so what gearing has everyone gone to on a 4x4 with 5.4L on 33's?

wxmcpo

For 33's you shouldn't go any higher than 4.10's, but I'm surprised with 3.73 stock gears you have to regear at all. 1800 RPMs at 65-70 doesn't sound too much off from stock at all.

jhunt47

i had 4.56 in mine with 35 and was running about 2000 rpm at 70 mph if you plan on staying with 33s go with 4.10 but if you will ever go bigger save some time and money now and go with 4.56s alot of people i know go to 35s and dont regear may want to get a programmer to get back the power and to change gear ratios too

p3ripperfw

well I dont "have" to per say...but I think the truck would perform better....the other thing I didnt take into consideration is could my shift points and speedo be causing some of this? Im thinking trying a tuner first would be the cheapest way to find out if the shift points are off......if I could get it to shift into od up near 2000 rpms I think it would be better but It just seems to be downshifting too easily

p3ripperfw

haha just as I was asking about the tuner.....cool man ill have to grab one and see how it does....I didnt think about it that much but maybe its just my shift points that are off?

wxmcpo

Your dealership can also adjust your speedo and shift points. Mine was going to charge me $80 to adjust mine, but I just got a programmer instead.

p3ripperfw

yeah when I got the tires I called and they said well we might be able to but its possible we might not depending on the tire size.....said it would be an hour of shop time and it would run 100 dollars.....just sounded to me like they would try and put me through the ringer if I even took it up there...Figured 100 bucks toward a programmer would be better spent