Blowndodge

I'm thinking of changing my 3.54 out for a 3.07. Don't tow anymore so Looking for someone that's done it and/or would know what to expect as far as driveability. I don't tow anymore and would prefer a betting highway MPG and lower RPM's. Is finding this 3.07 hard???? What about speedometer gear??

Douglas2

hey-Hey!!!,
I have 3.07's behind my NV5600 and love it. It is just about one gear up on the 4.10's the truck came with. At 60-65 it is an effortless cruise, even up a hill with family, luggage and a big Troy-Bilt tiller in the back. No way I'd consider 3.54's.
cheers,
Douglas

KD93

So, why not tow with 3.07's? I've been considering changing to a 3.07 for mpg's, (and maybe a Gear Vendors down the road ) but I still want to tow some. I was also wondering if anyone knew what's necessary to change the gears. i.e. do I need a complete axle/diff or can I just swap out the gears?

... sorry for the hijack...

lazerguy

Hey Blowndodge! I'm in the process of doing exactlty what you're talking about. With the rising price of fuel, I'm motivated. 3.07's are quite hard to find, though. First off, as a knowledgeable member said, you can't fit 3.07 gears in a housing designed for 3.55's. You need to swap the whole rear end. What we need is called a Dana 71, alias Dana 70-2UA. It's a special rear end designed just for the 3.07 gears.

I just found one 2 hours away for $500... I think it's a deal. Some junkyard guy told me they could ''probably'' find one for $1500!
Take a look at my recent thread ''Who's got a 3.07?'' there are a couple of members who said they would like to change their own 3.07's for 3.55's... maybe you guys could swap axles?
I didn't try it myself 'cause these gentlemen are located way too far from me.
Good luck!

TRENDZ

I have access to a factory parts catalog. The early 3.07 rears had a specific housing. The later 3.07 rears used the same housing as the others. If needed I can look it up and give the specific date of change.

KD93

I'd appreciate that!

Blowndodge

finding someone nearby that would want to switch with me is something I'd definitely consider for sure!

Douglas2

That runs counter to everything I have read about the 3.07 D70 variants. All required moving the pinion by something like 5/8" away from the ring to clear the large number of teeth( it has to be a third the diameter of the ring, and that never changed ). Love to see that catalog too just in case I am misinformed.
cheers,
Douglas

james1

So was a 3.07 ratio ever offered for the Dana 60 to fit the front of our 4WD trucks?

Sorry for the hijack.

apwatson50

There was a special front dana 60 housing, dana 61, that was made to offset the pinion further away from the ring gear.

For the rear I think there was enough room that no special housing was needed. Just the front.

dodgenstein

Special housing was needed at both ends.

lazerguy

Got my 3.07!
I opened it up and it looks real good inside. Just an open diff (no posi), so I'll have to transfer the power-lok carrier from my 3.54.

A perfect time to do the drum brakes too...

1992gen1_fan

I like my 3.54 but I sure wish the ol' getrag had just one more gear for highway. I'v gotten 19+ mpg's mixed with it, cant even imagine what i could've got with 3.07's under it.

jughead

my 90 came with 3.07. i added a 518 sure is nice 1750 rpm at 70 mph. if i need to move a heavy load usually on a hill i just use low range in the transfer case. only had to do that twice. usually tow race car with od locked out unless on level highway

AUGIE DOG

Was the 3.07 used in a D-350 / dually application?