Re-gearing from 3.73 to 4.10?

[MauiSportsmobile]

I have the 7.3L Diesel with stock size wheels and tires. I'll double check, but I believe my gears are 3.55's looking at the original window sticker and Quigley build sheet. I'm getting an Agile RIP kit installed and looking at going to 33's or 34's.

I would like thoughts on this from the resident experts...regear? What other upgrades would you suggest. Any input would be greatly appreciated.

[boywonder]

Ray/1der has a 7.3 and went with 33's and re-geared from 3.55 to 3.73......I imagine he'll be along here any minute....

[1der]

Originally Posted by boywonder

Ray/1der has a 7.3 and went with 33's and re-geared from 3.55 to 3.73......I imagine he'll be along here any minute....

Too funny boywonder!!

Yep, re-geared from 3.55 to 3.73 on 33's KO2's 285/70-17

Ran the 33's w the 3.55's and the gearing was too tall for me. Went 3.73's and still felt it might be too tall but also felt the 7.3 might be able to provide more power and the 7.3 was not quite right in its power output.

Next step was adding Hydra Tuner (after taking the DP out) w various mild tunes. That helped. Started using Hot Shots Stiction Eliminator oil additive and their gas additive to address what seemed like a couple of injectors not being up to snuff with only 95k miles on them.

After 5k mi of running the additive, the chip on 40 Tow or 65 hwy and a few long trips the 7.3 is running like it should and has a nice amount of power. So, the 3.73 gearing is a sweet spot - for us - with a van that tips the scales around 9.5k (at least ??) fully outfitted for a multi week trip. Maybe 3.90!would be perfect but 4.10 would be too much. Very comfortable cruise rpm of around 1800rpm at 65ish mph. EGT's w stock exhaust will climb to 1250F on a long climb. i have never used the 100 Perf setting. The 80 a few times to check it out. The 65 and the 40 are really nice.

We do have a shared boat/trailer that we tow occasionally. It weighs in at just under 4k lbs. I never feel the need to change the gearing. If we had something in the 6k lb range we were towing a lot, I would certainly consider changing gearing to 4.10, or even 4.56/4.88 if a really heavy trailer.

[boywonder]

Originally Posted by mgmetalworks

The carrier split is 4:56 I'm pretty sure.

Thanks MG!!

.....next question.....how do I determine what rear axle I have? Dana 60/70/80? Ford 10.25/10.5?

2008 Econoline passenger full float...axle code 34

Tag on the axle says

3.73 V8C24-AB
20 04457-2

[bigriver]

Originally Posted by MauiSportsmobile

I have the 7.3L Diesel with stock size wheels and tires. I'll double check, but I believe my gears are 3.55's looking at the original window sticker and Quigley build sheet. I'm getting an Agile RIP kit installed and looking at going to 33's or 34's.

I would like thoughts on this from the resident experts...regear? What other upgrades would you suggest. Any input would be greatly appreciated.

If you don't already have it you're going to want to upgrade to a full float rear end. These are heavy rigs and the addition of larger tires does add significant stress on the axles in a semi float rear end. A full float will alleviate any concern of potential problems down the road.

[boywonder]

..after a little wire brushing ......it's a Dana....not sure exactly what yet...


if the bottom number is a date code something doesn't make sense...it says 11 10 00.....and my van is a 2008


*EDIT..after a little searching apparently that's the P/N and date code for the cover, which hasn't changed in a long time.

[Annie O]

Oh dear I thought GOOD here is a thread than can 'splain how I find the axle/ratio/float/ and gearing because I'm trying to write my specs for a sale ad for HellBetty...


But all I see here is a bunch o Van'splaining! hee hee

[bigriver]

Heh... Van'splaining... I like it. Input your vin here it'll tell you everything you need to know.

https://www.ford-trucks.com/forums/vindecoder.php

[1der]

For Econoline vans, Axle codes from the factory are on the sticker located on the driver door B pillar. You can do a search for the code which will give you ratio and LSD or open diff. Add year and Econoline to the search for Axle code although it is pretty much the same from year to year.

Quigley - An email to Quigley with VIN, Make, Model and requesting build sheet and parts list for your van should be one of the first info requests made on a Quigley converted van purchase, if not included in the owner's packet. That Q build sheet will list diff ratio that it left Q with.

If a change in ratio was made subsequent to delivery from Q then you are down to estimating mph vs rpm and tire circumference, or yanking the diff cover.

re: Full float vs semi float - The ONLY way to tell for sure is to look at the rear axle with the hub/wheel cap off and looking at the center of the wheel where the axle hub shows. I trust NO listing stating full floater without a picture proving it. Even the Ford Spec/Sales sheets for a given model year and model are very suspect.

[MauiSportsmobile]

Originally Posted by bigriver

If you don't already have it you're going to want to upgrade to a full float rear end. These are heavy rigs and the addition of larger tires does add significant stress on the axles in a semi float rear end. A full float will alleviate any concern of potential problems down the road.

Thank you for the information bigriver and 1der! There is never a shortage of great information on this forum!