Switching to 3.54 for DD

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Switching to 3.54 for DD

Postby spencerdiesel » Sun Nov 01, 2015 6:10 pm

Hey there, I've been driving my 4.10 5 speed truck for 2.5 years. A while back my buddy let me drive his 3.54 geared rig, and now mine seams totally un-fun to drive........My commute is almost all highway and I have to keep the beast under 60 to get any decent mpg. And 2nd gear is way to low to start out in, I guess anyone who's driven a 4.10 truck knows what I mean. Anyway, would it be worth the time, effort, and mucho dineiro to swap 3.55s into my truck? It's 4wd so double the fun, thanks guys.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
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Re: Switching to 3.54 for DD

Postby thrashingcows » Sun Nov 01, 2015 6:34 pm

When I got my D350 crewcab it was a cummins/5speed and a stock Dana 60 with 3.54's. I drove it like that for about 3 years, got great mileage and loved the driving characteristics. Then when i did the 4wd conversion my donor truck had 4.10's front and rear...not what I was wanting, but the donor truck was too good of a deal to pass on it because it had 4.10's.

Anyway I build the crewcab and drove it with the 4.10 for about 6 months....and that was all I could handle. I know exactly what you mean about the Hwy and in town gearing. I had both my front and rear diffs swapped to 3.54's and had my Power-loc in the rear rebuilt at the same time. Think it cost me about $1700cdn to get it done, and I don't regret it even a little. ;)
1984/93 Dodge Crewcab, W350, 1 Ton SRW, long box, 330K Km's, M&H spacer, 366 spring, fuel pin to deep side, 14cm housing, Piston LP, PS IC, Isspro Boost, Pyro and tach, NV4500, 29 spline NP205, 3.54's.


Check out the build....http://www.dieseltruckresource.com/dev/ ... 05923.html
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Re: Switching to 3.54 for DD

Postby RumbleFish » Sun Nov 01, 2015 8:27 pm

I dont buy 4.10 trucks. I had a d250 i converted to drw and the axle had 4.10s. I was so unhappy i nearly sold the truck. I regeared and it was so much better.
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Re: Switching to 3.54 for DD

Postby ellis93 » Mon Nov 02, 2015 10:53 am

But how does it tow afterwards? What's the difference between the two when you need a truck to work like a truck?
93 D250 ,5 speed,4.11s,k&n autometer tach pyro trans boost guages,GDS 60mm h1c 14cm,honed 5x10,hplp/reg,1/8 timing,M+H M2 fuel pin, tims cooler tubz
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Re: Switching to 3.54 for DD

Postby Philip » Mon Nov 02, 2015 12:57 pm

If your running in mountains the 4:10's will do better pulling. If your flat land driving with small hills. The 3:54's give a better top speed with less engine noise.
93 W350 Club/cab w/duals, buckets & console, B&W flatbed, G56, 6 spd, 3:07 rears, gages, HX40/16, 4" exhaust, 6X.018 sticks, rear air ride suspension
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Re: Switching to 3.54 for DD

Postby spencerdiesel » Mon Nov 02, 2015 4:05 pm

Thanks for the input guys, keep the opinions coming. How labor intensive is swapping ring and pinions in both diffs? It would be a first time for me. I'm in college and taking diesel/heavy equipment, and I'd have help from several other guys, and input from my diesel teacher.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
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Re: Switching to 3.54 for DD

Postby RumbleFish » Mon Nov 02, 2015 4:43 pm

Indiana is pretty flat and my truck MIGHT see 10k behind it. Theres absolutely no reason for me to need 4.10s for what i do.

My dad had a 97 3500 nv4500/3.54 and pulled a 3 car wedge with it. Around here it did just fine. on his annual trip to pheonix a few of the mountain grades got pretty warm on the pyro.
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Re: Switching to 3.54 for DD

Postby thrashingcows » Mon Nov 02, 2015 8:18 pm

I haul through the mountains of BC...and have not had any issue with 3.54's. The only issue you might have is if your the type of person who "needs" to do the top Hwy speed up the mountain....me I'm a commercial truck driver so I'm used to pulling hills at 10mph. ;)

I just slow down, drop a gear or two, and pull the hill at what ever speed the truck is most comfortable at....just click on your 4 way flashers and take your time....You'll get to the top of the hill eventually. :D
1984/93 Dodge Crewcab, W350, 1 Ton SRW, long box, 330K Km's, M&H spacer, 366 spring, fuel pin to deep side, 14cm housing, Piston LP, PS IC, Isspro Boost, Pyro and tach, NV4500, 29 spline NP205, 3.54's.


Check out the build....http://www.dieseltruckresource.com/dev/ ... 05923.html
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Re: Switching to 3.54 for DD

Postby 2uphill » Mon Nov 02, 2015 9:34 pm

hear...hear :) ...
90 d350, SRW, 2wd, 727, stock, except banks i/c, 85K
84 w350 crew cab, I/c 89, s300, 727, 4x4, 130K
90 w350cc, 3.54, getrag, 125K
82 d350 crew cab project
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Re: Switching to 3.54 for DD

Postby spencerdiesel » Tue Nov 03, 2015 2:45 pm

Haha I hear ya, all good points. Before the 366, 76 wiiiiide open was a bit noisy, and I still got passed by yugos going through SC.
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
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Re: Switching to 3.54 for DD

Postby spencerdiesel » Tue Nov 03, 2015 2:46 pm

thrashingcows, how much would timing advance help my mpg? How do you like the spacer?
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
14mm rotor
 
Posts: 1106
Joined: Tue Oct 27, 2015 4:02 pm
Location: Brevard, NC
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Re: Switching to 3.54 for DD

Postby dmerlin25 » Thu Mar 31, 2016 10:46 am

I just trashed my rear Dana 80 with 3.55 gears about a week ago driving down the highway at 85mph with no oil in diff. I just bought a parts truck with a 3.07 D71. I'm gonna try it out for the summer and if I like it I am gonna have to find a D61 for the front. I'm hoping I can still pull a trailer over the mountain passes with out much trouble. The 3.55 gears did serve me well, except that Montana just raised the speed limit again and I like getting where I want to go in a timely manner. I like competing with the new Cummins trucks.
Never shoot a large caliber man with a small caliber bullet. Semper Fi
1993 W250 LE G360
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Re: Switching to 3.54 for DD

Postby spencerdiesel » Thu Mar 31, 2016 12:25 pm

How built is your VE? There's several guys here running 5 speeds and 3.07s. Most everyone that has them seems to like them.

I'd imagine you'd never grace 5th when towing though
1992 W250, 5 speed, 4.10, Ext. cab Ext. bed, 12.5k winch, 75 gal. fuel tank

H1C/18

Fuel: THD 6x10 VCO sticks, THD 12 psi piston pump, THD fuel pin, 366 spring, fuel screw 2 turns in, timing to the head/ >1/4”
Muffler delete

Minimum 60% WMO full time since Sep. 2018
spencerdiesel
14mm rotor
 
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Re: Switching to 3.54 for DD

Postby BILTIT » Thu Mar 31, 2016 12:40 pm

Spencer- i have both dana 60/70 powerloks for sale, just what you need when doing your gear swap.

Might not be the most economical to ship from way up here though.
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91.5 W250, coolertubz, HE351CW, PS IC, Alcans, GVOD, Valair DD, bags, crossover.
1974 Pontiac Ventura,best of 11.97 at 112 so far.
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Re: Switching to 3.54 for DD

Postby dmerlin25 » Thu Mar 31, 2016 12:45 pm

I've been reluctant to turn the pump up too much without more air first. I'm shopping for a HX35. I'm curious what RPMs would be in 4th at 70mph. Time for some math!

Just figured it out. 2200 at 70mph. Not bad at all for up hill towing.
Never shoot a large caliber man with a small caliber bullet. Semper Fi
1993 W250 LE G360
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