As the title says, have an 01' V10 with 35's. Looking at regearing as the big hills in the Colorado Rockies are no fun when towing. Currently have 4.30's but I know it would be easier on the drivetrain to regear.

Looking at changing to 4.88 or 5.13 gears in some new to me axles, D60 front and another 10.5 rear. Anyone have experience with 5.13 gears and 35's?. I know it will work and isn't a bad idea just looking for firsthand experience.

Thanks!

 

No, not 5.13s and 35"s, I currently run 4.88s and 35"s for an effective 4.39 ratio and it does very well with the 11k TT and our Eastern mountains.
I did run with the same gears and 32" tires for two years and it was like a locomotive! . But the unloaded mileage suffered a little, went from stock highway averages of 14 down to 11-ish MPG. The towing mileage increased from the stock 3.73 setup of 6 to 7 MPG to a solid 9 MPG after the gear change. Back then we were pulling a 9,500 lb toyhauler, we now get the same towing mileage pulling the 11k TT with headers and custom tunes.
If you are towing heavy in the Rockies then those deep gears will be a real improvement but expect to drop some MPGs when unloaded.

 

Keep in mind, there will be more heat with the lower gear, so make sure you run a good oil and possibly a bigger diff cover.

But I'd run that gear. I ran 4.88s in my old Ex, and it was great. But I started with 3.73. So a step from 4.30 to 5.13 would be about the same knoticable difference.

 

I didn't add the temperature sensor to my rear diff until after changing over to the 4.88 gears, so I don't know what the temps were in the stock configuration. But now with Mobil1 75W-140, an OEM '08 finned aluminum cover (not oversized) and the deeper gears at ambient temp of 70 to 90 degrees the diff temp runs between 160 and 205 typically, that is all while towing the 11,000lb TT. The highest that I've seen the temp go was about 225 on a very hot day while climbing some steep mountain grades in VT and the temp dropped right back down to the normal range once we made the summit. It's also pretty remarkable how much and how quickly the temp drops with just a little bit of rain, once the road gets wet enough to have some spray it will drop 30 to 40 degrees.

 

I WANT YOUR 4.30s

 

Looking at this as a long term solution hence the 60 up front. Not sure I "need" a 60 but there are benefits to regearing different axles that can just be swapped in on a Saturday. Its the daily driver so cant have much down time.


Made a chart for RPM's at different speeds and also in different gears. The Ex is fine in all instances except the big passes and I end up in second gear and have seriously feared not making it or ending up in 1st gear doing 10 mph.


I guess another good question is what RPM do most consider the "sweet spot" for towing/cruising? Along the same lines at what RPM are you over revving the motor for normal highway driving for sustained distances? For example with 35's, 4.88 gears, at 65 mph you are at roughly 2187 rpm. While the same with 5.13 gears you are at 2300...


Yes if I do go through with this idea then I would be selling the "old" 4.30 axles with something like 60K miles on them. That is another factor, could pass on a good set-up to someone who isn't running bigger tires.

 

I'll be here waiting

 

When you do, please make sure you don't advertise in any of the tech forums.

Please post in the classified forum or make contact with any interested parties via PM.

Stewart

 

Stewart absolutely, not looking to start a for sale thread here. It would be some time before the old axles would be available...and that's if I go through with all of this.


Thanks again to all those with input!

 

The day I had my new 35"s mounted I went out on the interstate before and after to gather a little data (I like driving and this way is more fun than just using a calculator ) and this is what I recorded. Using a GPS for the speed and the digital tach readout on my Ultra Gauge this what I recorded.
Speed............RPM 32"s..............RPM 35"s
50.................1930....................1720
55.................2075....................1900
60.................2280....................2055
65.................2430....................2230
70.................2595....................2400

As far as a sweet spot for towing (my EX sees very few unloaded miles) the run I've made that most impressed me so far with the current setup was made on 89 octane gas with a 5Star custom 89 Performance tune. Towing 11k through the Blue Ridge Mountains on I-77 and I-81 (virtually NO flat sections) I was able to hold OD on all but a couple of the steeper/longer grades by hitting the bottom of the climb at 72/73 MPH and letting it bleed a little speed off on the climb with throttle openings of 60/65%. 2200 to 2400 RPMs had it running very strong! That trip was 582 miles (Charlotte to Philly) with a moving average speed of 60.1 MPH and hand calculated out to 8.75 MPG. On other towing trips I've run in the mid 60s cruising with a lot less hills on the 87 gas and tune and have seen a best of 9.25 MPG. On a trip to Savannah from Philly with only me onboard and not towing I set the cruise at 65/70 and got just a hair under 13 MPG.

 

Tom thanks so much for your first hand accounts, much appreciated. I know 4.88's will be a good choice, just curious if the 5.13's would be a "bad" idea and I don't see how they could be. From most of my math you are looking at maybe 200-300 rpm difference and being at 5K plus elevation everyday I have less "fuel" to work with.


I wonder how much of a difference "where" the driving/towing we all discuss takes place. For example, when I am going up a 7% grade on Vail Pass at 10.5K+ft elevation vs. the Blue Ridge Mountain Parkway at a max of 6,053 ft (info via google). This is a serious question, should this info effect gear ratio selection?


I toss in the info that I may want 37" tires in the future and the 5.13's make much more sense....


I like discussions where details can be shared so sorry if Im getting a little too into it...

 

I hope my last post didn't offend anyone, from what I have gathered thus far no one is running 5.13 gears with 35's and the V10. I am still open to the idea as the V10 likes to rev. If bigger tires are ever in the plans it makes sense, if 35's are the max then 4.88's are probably the right choice. I don't drive much at 75 mph but it does happen.

I picked up the 2004 chassis with D60 front and 10.5 rear a couple weeks ago, getting everything cleaned up and ready for the gear change but it might take a while. Lots of little expenses add up. Front shafts need u-joints for sure, might try to use the current unit bearings, and will probably install new ball joints since I'm in there anyways. Add new brake rotors, pads and the random seals etc and this isn't exactly a "cheap" upgrade.


Any input on ball joint brand? I have heard Moog quality isn't what it used to be and a lot are going XRF? Already bought Spicer u-joints and I'm good with that. Need to have the front driveshaft rebuilt and balanced as well.


Thanks to all for the input!


If I could do what I "really" want I would go this route...


Just Differentials Ford F450 4x4 Motorhome on 42's Build Thread - Expedition Portal


41's with some super deep gears...

 

The extra elevation in your area will rob the V-10 of a little bit of power, so with that in mind those deeper 5.13 gears seem like an even better idea.
Like I mentioned earlier, I did run 32"s with the 4.88s for two years and thousands of towing miles, never once did I feel that I was over spinning engine for the job at hand. It happily spent several 10 hour days at 2300-2500 RPMs with a combined weight of 18k+ lbs.
I remember reading about that linked to camper build a while back, pretty cool rig and it's an "Xcursion"!
I still have to get my 4.88 front axle swapped under our EX, I have debated if I should redo all of the same stuff you are looking at too. Mine was reported to be very solid when removed from previous rig and it already has replacement ball joints installed (unknown manufacturer), but still would be nice to know its all fresh with top quality parts. If I do ahead with the refresh I will be using the XRF ball joints.
Keep us posted with your progress.

 

i live at 8700 feet in the rockies and have set up a few rigs to run the hills.
4.56 gears and 34 inch tires seem to do pretty well and i have seen quite a bit of improvement in gas mileage with that, but it was in conjunction with other mods,


CAI, throttle body, cat back exhaust tuner etc.

If you have already addressed the ability of your rig to breath then look at the gearing, but if you are still running the stock intake etc. do that first.

BTW i just had my gears done in the ex. 4.56 and will be running a 295/70/18 tire, 34.3 inches roughly. I feel the combo will be just about right. i am still on the 285/70/17 till tomorrow (new tires and rims just arrived) i am seeing 14-15 mpg hand calced running the through the mountains (3-5 over)

On the flat highway i think the 4.5 and 33 inch tire is too deep a gear 2450@70 mph with the bigger tires i am thinking the 4.56 will be a nice compromise and will get about 2200 at 70 mph.

pm me if you need a referral for your gear work, just had mine done $1000 parts and labor,

the power pack from 5 star tuning will be here soon also. headers,ypipe and tuner.

 

The EX comes from the factory with a good Cold Air Intake, don't waste your time changing it out for something that will only increase the noise not the output, just keep clean OEM paper filters in it. . Honestly the factory setup can outflow the engine at redline and aftermarket CIA setups have been tried by many members here that have reported no performance gains over stock.