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Towing and Hauling Towing and hauling with Ford diesel trucks and vans.

Thread: axle gearing and towing up hills Reply to Thread
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  Topic Review (Newest First)
04-12-2019 09:43 PM
montibank So ... long story short ended up with 4.88 gearing. A little bummed I didn't have to go up to 37" tires to 'fix' my mistake but 4.88 with ~34" tires is pretty *****in for towing. Fuel mileage not so much but that was not a problem I am worried about. Next up... get the speedo fixed so I can figure out my range on a fill up.
01-13-2019 02:11 PM
montibank zf5 ... manual not automatic
01-13-2019 02:10 PM
montibank Oh ... it already has a factory turbo. Not that it wouldnt do the job... it did just fine if I was willing to go 35 mph. 120 miles at 35 vs 120 miles at 55 mph is a huge difference in time.
01-13-2019 02:07 PM
montibank "Towing waaay to much weight" yes likely.

Shop goofed and put 4.88 in it, thank god they did. Gearing is spot on for what I wanted rpm at 55 in fourth and 65 in 5th with 315s on it. In break in now so can't pull my trailer to test. Kinda wish I did have them put positraction in it. They called halfway through the job and I said no. Regeetting that choice already... Had to put it in 4wd to get up my buddies driveway the other day. His driveway is dirt, it was raining, and it is a really steep climb.
01-05-2019 11:42 AM
So when you are towing at say 60 mph and you come up to a hill and start to slow down does you truck tranny shift out of overdrive? Simply dropping a gear lower in tranny will give you higher rpm and more power. What are your EGT temps and what is the location of the probe.
01-05-2019 09:05 AM
wpetko Regearing a 4x4 truck is a big red flag for me because you would have to regear the front axle as well. I would first research auxiliary transmissions like Gear Vendors before I got into the differentials. Also, unless you are towing WAY too heavy & your truck is overloaded a 4.10 gear should be completely adaquate for any hills that you find in Florida. If the truck is having a hard time towing with your present ratios then maybe you should consider adding a turbocharger or other engine upgrades.
01-03-2019 07:58 PM
Randy 4614 I have a 93 dually with factory turbo , 4.10 and ZF5 trany. 215 tires , factory size. When first got the truck , used, it had a wide ratio transmission it. I pull close to 18000 to 20000 # behind it. Had to be really careful starting or backing up on much of a grade. Had transmission problem so rebuilt it to a close ratio. Lost about 10 mph on top end , but now it will pull. We have some pretty good hills and mountains here in Montana. Yes it pulls down on the hills , but still gets me there. Get around 15 empty and 8- 10 loaded , still run down the highway 65 -70 pretty easy. this is what I pull with mine.
01-03-2019 03:51 PM
montibank Side note my truck is NOT a daily driver. It just tows my junk from place to place and pulls tree stumps.
01-03-2019 03:12 PM
montibank 1989 F350 7.3
Banks Sidewinder
ZF5s manual
stock tires were 285
now 315
stock gearing 4.10
installing now 5.13

Before gearing would lose speed uphill at 55 in fourth but on the same hill would hold 65 mph fine under ambient temps of 90 degrees F pulling my trailer.

My goal ... like OP is to be able to hold 55 in fourth vs. any hill when pulling my rig.

On flat ground 5 gear is stupid tall... I have no business doing 85 mph in a 30 year old truck.

Fingers crossed 65mph (actual) is around 2500 rpm if in 5th and 4th @ 55mph is around 2800 rpm.
03-05-2012 08:50 PM
burlhall I bought a new 92 ford F250 with the 7.3. It did alright but I wanted a little more performance out of it. So, I put a Banks sidewinder turbocharger on it and did it ever make a difference. I made several trips over Mount Eagle pulling a trailer that weighed about 10,000 pounds. Before I added the turbo the truck would pull down to about 35-40 mph going over the mountain and at the top I think the E40D was in 2nd gear. After adding the turbo I had no trouble pulling the mountain at the 50 mph speed limit. The truck could maintain that speed in 4th gear but I would shift it down to 3rd to keep the egt's down.
02-10-2012 02:44 AM
JESSE 1 We bought a new '88 F-SuperDuty (450) diesel and the only gears offered were the 5.13. The truck would run 70 mph but you'd be pushing 3000 rpm if I remember correctly. Just not a lot of power in the N/A 7.3. I had a '94 F-350 dually with the N/A 7.3 Turbo (factory) and was really surprised how much more power the turbo provided. That was still a simple engine but quite a bit more power than the non-turbo 7.3.
02-04-2012 05:10 PM
Originally Posted by drinkypoo View Post
When you don't have plenty of power is when you need more gears. We don't have room for that much transmission in the pickup.
True.... Most semi's I see now have 10 speed and 13 speed as normal transmission. Hardly see the 15 and the browny box.

Gear Vendors makes an under/over.
Actually, their unit is just an "over drive". They advertise "under/over" because you can split the gears. Like you shift to 2nd gear, but don't want to go to third, you engage the over drive and split second to make a 2nd-over (some hve/could call it a 3rd-under). Speed up, then shift to third and turn off the OD... The options are 1:1 (off) and .78:1 (on)

I have a Gear Vendors on my pickup. It's not like the TRUE underdrive that US Gear offered. The US Gear under drive actually lowered (numerically) your final drive ratio. When it was "off" it would be 1:1 ratio. When you turned it on, it would be like 1:0.78 (sorry for the bad example...). It would turn a 3.55 axle closer to a 4:10. At least that's how I remembered it when I use to read it on their website before they went away.
12-20-2011 05:53 AM
Originally Posted by Kaliburz View Post
IWhen you have plenty of power, you can have a 13-15sp tranny to play with.
When you don't have plenty of power is when you need more gears. We don't have room for that much transmission in the pickup.

It's too bad that the old US Gear "under-drive" is no longer being made.
Gear Vendors makes an under/over.
12-20-2011 12:59 AM
Kaliburz I have an IDI van and it has 3.54 axles ratio. Just to get up a good incline at 65-70MPH, it usually has to downshift out of OD.

Gears and gearing play an important roll on how fast you slow down on a hill. Look at the semi trucks today and of yester-year. HP today is easily in the 600-700HP range. When you have plenty of power, you can have a 13-15sp tranny to play with. Older semi trucks had their normal transmission and a brownie box (some even with a three speed rear axle- under-direct-over). The brownie box created a multi speed transmission. I have seen a six speed manual transmission with a four speed brownie gear box (that's 24 gears to choose from) and that's with a 350-400HP semi truck (older 70's era).

It's too bad that the old US Gear "under-drive" is no longer being made. You could leave your ratio's alone and the under drive would give you a different ratio (higher number). For example, I think when used with a 3.73, the under drive would give you a 4.10 ratio when activated.

In your case, if you used one, you would be able to switch to the (higher numbered ratio) to tow and when going empty, leave it off (direct) and it would be your normal "as is" ratio.

Or you could try installing a brownie box after your transmission. Someone online did on their truck... not sure which forum I saw that on....
11-30-2011 07:05 AM
nitrogen being 4x4 you will need to regear both ends, you need to factor that into cost as well. I drove a "old" superduty with the 4.88, could not make it past a fuel station(6-8 mpg) and 65 was pretty max rpm. 5.13's if you can 55 you will be doing good. at that point an aftermarket turbo kit will be cheaper,lower maintenance, and much more satisfactory to drive. if you don't believe me just set the cruise at 55 now on the interstate and see how long it takes before you are pissed off at seeing EVERYONE pass you
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