Considering a 6" lift... With that, Im interested in how important it is to re-gear to 4.10s if I run a 37 with it. Truck is stock with 3.73s, I don't tow much, just a small camper and a car occasionally, nothing more than 5000-6000 pounds. If i run the 37's without going to 4.10s will that wreck the tranny, or just make the truck a total dog when I'm towing? Kind of a rookie question I know, never ran a lift/tires this big on anything before and of course im doing homework on my own but Im looking for your input...
Well I got an 8 inch lift with 38's on it and I also got 3.73's. I have never towed anything yet so I couldnt tell you how good it is while towing but unloaded or stuff in the bed it isnt horrible. My intake, exhaust, superchip probably help with that but I dont have any issues. But I would imagine it might hurt while towing. Someone else can chip in. And I am still get approximatly 13 MPG with purely only stop and go so. Thats my experienced. If I boost launch it will still smoke the 38's on accident lol
Without re-gearing, you'd really hurt the MPG on the setup. I've also heard that a 6" lift (which is what I have) will still rub on 37" tires (which is what I want). I don't think the transmission would be a factor, provided you have a good tow tune that tunes the transmission. I don't tow anything, but I've listened to what others have said and this is what I've taken from the majority of conversations.
Yep, sure is. 35s look a tad small on my truck to be honest... but I've just recently started hearing that 37s rub on a 6" lift. Looks like I'll have to go bigger on the lift to fit 37s without rubbing and/or trimming - which I'm not gonna do. So, I'll stick with 35s for now.
Honestly, its not worth the money to go from 3.73's to 4.10's. Very little difference, and most people will go up to 4.30's for that reason. If you end up with 35's instead of 37's, then definitely keep the 3.73's.
Yeah, i do kind of like the small goofy look if the tires are poked out a bit. weird i know. but yeah 4.10s with 35's wouldnt be much fun except leaving stop lights. Would result in pretty poor gas mileage on the highway. Dont feel like spending the money to regear if I'd be best off to go with 4.30s.
I know I'm comparing apples to oranges, but my 6.0 came with 3.73's and the tires were 34" in diameter from the factory. Aftermarket 35's with rims are a little heavier and wider and you'd notice a difference in performance going to 4.10's, but the cost of re-gearing doesn't really make this a good decision IMO. When I went to 8" of lift and 37's, I drove on the 3.73's for a couple of months until my TruTrac showed up. I went to 4.30's and the truck is turning slightly higher rpm's at highway speeds, but I would absolutely recommend re-gearing if going 37's or bigger. Not only to try to get back to the engine rpm's "sweet spot," but to offset the additional weight of the tires, rims, and lift kit (and the decreased aerodynamics of a lifted truck).
I think you guys are a little confused on lifts, tires, and gearing. I am not here to put anyone down, I just want to share what I have learned though years of off-road and building Jeeps. I understand that these are two different vehicles but the principals are pretty much the same. There is a mathematical formula for the selecting of gears to tires, here is a link that can walk you though it Gearing Up for Taller Tires! · Superlift · www.superlift.com in our trucks the main reason for regearing with larger then factory tires is to save the final drive ratios of the transmission,with the lower rpm the transmission will be pulling overtime shifting between 5th and 6th gear, you also want to regear to regain the performance and mileage lost by the added rotational weight that you put on the vehicle. You can get by with not regearing on 35's but fuel mileage and performance will be degraded. Here is a video to look at and think about FUBAR BIG TIRES KILLS TRANSMISSIONS - YouTube I don't agree with everything this guy says, but he explains this point pretty well....
Agree with you Duncan, and my point was that fuel economy and performance would not be degraded enough to justify spending the money on gears. Especially going to 4.10's, and I think you'd agree 4.30's are too low for 35's on a 7.3.
It all makes perfect sense:rofl: ill be keeping the stock gears and going with 35's with the 6" lift. Thanks to you all for confirming my thoughts and learning me a bit too. :thumb:
I run 37's with a 3.73 and while I haven't been disappointed in my towing (Nothing heavy, motorcycle trailers, cattle trailers etc.) I am dissatisfied with my highway mileage. I'm lucky to get 13MPG going 70 down the interstate and probably likely to get 12-12.5. That would be my biggest motivation to regear, especially if I do go to 40's when these tires run out. What does a regear to 4.30's normally cost?
Putting 4.30's in with my 37's was one of my best mods. Lower trans temps, lower EGT's, and better performance all the way around. I actually picked up 1 mpg and the truck is so much more fun to drive.
Snake your right I do agree that 4:30 is too low for 35's and a V8. I personally would look more to the 3:90 to 4:11 range of gear selection. OP I just called my contact in 4wheel-parts of Dallas and was quoted 1700.00 for a complete re-gear. That included parts labor and fluids.
you must have an 8" lift to run 37's or a 6" with trimming being done for that size tire, it will be much cheaper and less hassle in the long run to do a 6" lift with 35's. no regearing needed for that setup.
thats the way im leaning now. maybe down the road jump down to a 3.90 or 4.10 as mentioned before but i dont think im gonna have that extra $1700 off hand right away.
Yeah, I have a 6" with 37's and even with what seems like excessive trimming, she still rubs when it's turnedf if the road isn't perfectly smooth. I've heard you can even get away with a 7" lift much more successfully than a 6".
4.10's are fine with 35s but highway mileage suffers a bit. I usually get around 16.5 if I can keep it around 60mph, after that the rpms are over 2k and mileage drops. Stop and go I stay roughly 14mpg. I would rather have 3.73s for the highway mileage though.
I ran pro comps 6.5" lift with 37s and no trimming. 37x12.50x20 swamper ssr's. Pass side would rub if I was turned to the right and ran over a curb... But it only rubbed a couple times lol
I forgot to mention earlier that some guys will need a speedometer recalibration or an after-market tuner like the SCT so that you can change the tire and gear parameters. Not doing so will throw off your speed and mess with the ECM. I believe that the dealerships can adjust up to 35's, hope this helps.....
i run 37s with the stock 3.73s and i wish i had some 4.30s, especially when towing. i know my around town mileage would pick up and it would be easier on all other parts, ie: tranny. but if im going to do it i will do it right by changing out both diffs and front and rear at the same time which is going to cost a pretty penny
I run 295/65/20's that come in at 35.4. I would really like to throw a set of 4.30's in it. As it sits now the truck wants to run at 80-85mph and I have to really pay attention to keep it down to 70. Also with a bigger turbo you really need to keep your revs up some to keep the turbo spooled up. If I was going to 37's I'd really consider 4.56's, and 4.88's with 40's.
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