acbarnfinds

So I was talking to a gear guy a few days ago and he said because I have 3.07 gears in the rear they can not be changed to different gear ratio. Is that true? I'm now running a nv4500 and can do almost 95mph..not a good thing for the amount of weight I haul. I'm open to suggestions.


Thanks

RamGuy84

I believe you have to change Carrier ? But didn't the 307's come in the Dana 71 like the front 61 ?

oliver foster

You have a Dana 71 rear axle with 3.07 gears.
I don't believe there are ANY other gear option you can use in a Dana 71 axle.

The Dana 71 axle is not a Dana 70 axle.
The "pigs head" is a different design to allow the bigger ring gear needed to get the 3.07 gears to work.

My black crew cab, with 3.07 gears, a NV-4500 and running 33 inch tires, I do 82 MPH at 2000 RPM, and yes speeding tickets are a legitimate worry.

Philip

To change gear ratios you would need a spacer to move the ring gear over. There was a company making them many years ago. Finding one now a days would be about impossible.

The carrier is the same from 3:07 to 4:10's. So a carrier change would do nothing.

There was a guy on TDR many years ago that installed a set of 3:54's into a 71 axle. He used a 4:56 and up carrier and did a lot of machine work to make it work. With the cost of machine work. You could buy a deeper geared axle and rebearing it most likely.

j_martin

Find a 92 or 93 rear axle with 3.54 gears in it, check it out/refresh it while it's out in the open, and stick it in.

Some speed demon here would want your 3.07, so you could recover some cost.

sooty

that what I changed my ramcharger to, 3:54, if you go to eastcoast gear supply, looking for dana 60/61 tech, for gear change youll need a narrower bearing race, and a dana 60 carrier, moving it closer to pinion, then use spacer and shims outboard of opposite carrier bearing to close gap, it was easy, but time consuming for me adding power loc carriers, with mods, some choose to keep the hi-ratio, im sure others will chime in.

BILTIT

With my GV on and in 5th, 3.54 gears and 33" i am at 81mph at 1800rpm. Interesting comparison to your setup.

Acbarnfinds - I can bury 95mph no problem, doesnt mean i do it though and especially not while towing. What weights do you tow and for what distance?

acbarnfinds

Thanks guys, good bunch of info.


I'm hauling a 4100lbs trailer, backhoe weighs 9100lbs. Truck itself ways right under 5000lbs. I'd say with the two other buckets, chains, winches ect.. I'm probably right around 22k total on average. My last weigh in, with a Farmall 560/ loader/ disc/ plow was right at 21,565lbs, that's when I still had the 727 in it. I usually haul 10-50 miles depending on job, then maybe once month I'm over the pass into Central Oregon.


I was thinking 3.73? My 1998 1 ton had 3.73 and would do roughly 60mph (about 50mph over pass) loaded and staying out of OD on the NV.
What years should I be looking for to just drop in? no cutting or welding. I'm also up for putting a dually in it dana 70 or 80. Anything helps, thanks guys/gals

BILTIT

4.10's

acbarnfinds

Will a later model dually rear end bolt up?

BILTIT

Many people put in Dana 80 ' s.

Do a search and check the sticky, should be able to find the info you need. I don't know off hand what will fit.

Redtruck-VA

My 89' 3:07 Dana 71 uses a 4.188 U Joint with a 1.188 diameter cup. If the dually uses the same U Joint I would think it would fit.

MrFusion

I believe the the 3.07 rears have 35 spline axles (Dana 71) and the later rears have 32 spline axles (Dana 70-2U). The 35 spline axles have the taper cone washers and studs in the hub, the 32 spline axles have bolts in the hubs. Makes a difference when you're looking at carriers.

Redtruck-VA

Yep, my 89' Dana 71 has studs and 35 spline axle.

mknittle

My 3.54 Dana 70 has the studs with cones.