zf 5spd towing

[dizdak]

my truck is factory 5spd, gearing is the 3.54 or 3.55 gears.. probably half the miles or better i put on my truck are towing my play toy or a buddies toy..it is a slug with 5 or 6k lbs behind it until i hit 45-50mph then all is good.. have any of ya'll upgraded to 3.77 gears like the super dutys run and if so did it help getting off the line with the manual trans? next choice up would be gear up to 4.11s but i think that would be tooo much with out a load behind it..also i am just running a stock size tire..

 

[ocnorb]

Mine also struggles on the bottom when hooked to my 12K 5th wheel.

I am saving up for the correct adapter to put my Gear Vendor overdrive back in. After this is done I am going to 4.56 gears in the rear. With the GVO it will run about the same rpms as it does now for those empty runs, and have the deep gears that should make rocky mountain passes more bearable.

In your case I think 4.11's would be a good compromise.

 

[Diesel_brad]

From the sound of it, your truck is not running right. Alot of the guys on here will tell you 5-6k is nothing, they tow 12k regularly with out a problem


The best fix for the "IDI zf5" is the powerstroke ZF5 or the guts from a 460 ZF5.

The problem with the IDI zf5 aka s42(87-95) is the TERRIBLE 1st(4.14) and reverse(3.79) gears. They are entirely to HIGH and it makes you slip the clutch too much.

the Powerstroke ZF5 aka the s47(95-97) has a lower 1st(5.08) and reverse(4.66)

the 460 ZF5(came as both the s42 and s47) have an even lower 1st(5.72) and reverse(5.24)

 

[dizdak]

sounds good, 1st is very low... when not hooked to something i usually take off in 2nd but that really isn't a good "hooking" gear, on take off from a stop you can feel the lag until you hit a couple mph... i am also gonna upgrade the clutch this coming year too.. my only concern with the 4.11s would be the non-towing rides.. seems like it would turn the rpms up when running with traffic with out a load on it.. Is the power stroke ZF a direct bolt up?

 

[hesutton]

If you could find an underdrive unit, that would help while towing, but you keep the 3.55's for empty driving. I have a US Gear underdrive on my crew cab and use it in the city when hauling the fifth wheel. Once on the highway I take it out of underdrive and cruise on. The problem is......US Gear is out of business.

Heath

 

[gunz]

If you were closer i would trade you complete axles. i have a set with 4:10, and my rear is a 3:55. I dont have a transfer case yet. But i could see where towing with 3:55 might not be ideal in every case.

 

[TWeatherford]

I have 4.10's in mine and like them pretty well. Most of what I do is not towing. The best I get is 17 mpg, usually 15-16 though that was with an IP I found out was timed 3.5 BTDC. Now that its set at 9.0 BTDC I should do a little better.

Mines always been pretty gutless with much of a load behind it. Heaviest I hauled that I got weighed for was 14k combined, with a tall flat front two horse trailer, definitely slowed down a lot for that. I've never had a problem with my ZF5, first and reverse have always been plenty low for me although I haven't hauled many big loads. I still start in first all the time, helps save the clutch.

 

[dizdak]

i will look into the underdrive options...

 

[flareside_thun]

My truck is a **** anyways....But, with 3.73's it's even more of a ****.

 

[gonecrazyi]

Mine pulls pretty good with a factory turbo 4.10s and 38s. Does decent with a trailer once moving. I usually cruise st 70 pulling my trailer. Hopefully it will pull harder with the actual 093 turbo with the 390 inch downpipe.

 

[dizdak]

gonecrazy - mine pulls great at hwy speed, pretty much anything above 45-50 and it's all good.. i am just wanting to get moving off the line better, i think gearing up a little will get the results i want..

 

[gonecrazyi]

When I get my 093 kit on you'll have to come take her for a test drive.

 

[dieselcrazy]

i have a 1991 ford f350 crew cab with 7.3 idi and zf5 speed and 4.10 gears and pulling is great. plus its 4x4 the down side is iam getting 10 or 13 miles to the gallon

 

[dizdak]

gonecrazy - what part of FL you in? mileage wise i don't do too bad, i think with a little more gear i would do better since i wouldnl't have to be in the throttle as much to get moving with traffic..

 

[Dieselcrawler]

With my dually I got 4.10 gears and pulls ok, but I was teased as my previous tow rig was a dmax. I am happy with it he'll it gets 18+ mpg empty cruising at 60