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chevynut
10-24-2015, 06:43 PM
I have 4 gearsets for my Dana 44 that i could use. Aside from the slight gear ratio differences, which gearset would be best to use:

41-10 (4.10) These are Dana Viper gears from Mopar
37-9 (4.11) These are aftermarket gears, but I don't know where they're from
45-11 (4.09) These are Dana gears but the pinion has a sleeve welded to it to make the bearing surface larger. That means the pinion shaft itself is smaller.
41-11 (3.73) Dana gears

I am leaning to using the 4.10 Viper gears but was wondering of a 10 tooth pinion was any stronger or weaker than an 11 tooth.

I'm trying to decide which ratio to use as well. I'm considering the 3.73 gearset instead. I have a 26.1" diameter tire with an effective diameter of 25.2" per TireRack (295/30-18). At 75 MPH the 4.10 gears put me at 2052 RPM and the 3.73s put me at 1867 RPM. I have a 2.66 first gear and a 0.5 overdrive 6th gear. Which ratio do you think would be best? I probably won't drive this car a lot on the highway, but I might. ;)

I am disassembling a Dana 44 so I can get it rebuilt so I need to decide on gears.

Rick_L
10-24-2015, 06:55 PM
Your 37-11 combo is a 3.36 ratio if the numbers are tooth count (and they should be). So that's a different situation altogether.

In general, less pinion teeth is not as strong or durable for similar ratios because while the individual teeth are bigger, there is less load sharing.

Whether you go with 3.73 or 4.10/4.11 is a matter of rpm and torque. You have a T56 6 speed, correct? Go with the 4.10 or 4.11.

I went with a 3.89 on mine, a friend has the same - it works. But given the choices I'd opt for more numerical gear, not less. But it's splitting hairs, either will work.

chevynut
10-24-2015, 07:17 PM
I fixed it...it was 37-9 for the 4.11 gears.

Thanks for the feedback. Yes I have a Viper T56 with a .75 5th gear and .5 6th gear.

The difference is 10%. I don't know if 200 RPM is splitting hairs or not ;). I think my truck runs about 2100 at 75 MPH.

The 3.73s would give me an overall first gear ratio of 9.92 and the 4.10s would give me 10.91.

Rick_L
10-25-2015, 08:52 AM
Seems to me the overall 1st gear ratio with the 4.11s is better. Depends somewhat on traction. One thing I've noticed is that while more overall gear ration = more torque multiplication - more ratio is also more forgiving if the tires do spin.

markm
10-26-2015, 07:30 AM
I would like to put one of those 6 speeds in my 67 SS 350, it has a 4.10 12 Bolt posi and I thought that was about right.

chevynut
10-26-2015, 07:50 AM
mark, what was the first gear ratio in your transmission?

markm
10-26-2015, 08:02 AM
Current Trans is a BW Super T-10 with a 2.64 low.

chevynut
10-26-2015, 08:30 AM
Thanks for the feedback guys. Well I'm going with the Mopar Dana 4.10 gears. I have parts of an install kit and don't know if I should get another whole kit or just re-use the parts I have. I don't know how many miles are on the differential, but it looks pretty good as far as I can tell. I'll remove the carrier and check out the bearings. I have a couple of new bearings (not sure which pair but I think for the carrier), a new pinion seal, two new crush sleeves, and a couple of new pinion nuts. What I don't have is the other two bearings, a clutch pack, side yoke bearings, or side yoke seals.

Why does everyone say you have to replace the ring gear bolts anytime you change ring gears? That sure seems excessive but I have a new set. I might see if I can find someone locally to rebuild this for me so I don't have to buy a bunch of new tools. ;).

Bihili
10-26-2015, 08:44 AM
With my .50 sixth gear and 295x45x18 the 410 ratio twelve bolt is everything I expected and more.
With your 295x40x18 the 373 will make your cruising enjoyable.

markm
10-26-2015, 09:49 AM
I do not change ring gear bolts unless they appear worn or some other good reason. A 4.10 x .50 overdrive gives you a top end that needs a Vette suspension.

JT56
10-26-2015, 10:55 AM
Sorry a little late on my replies. I guess it depends on what your doing with it? Say stay within 50 mile radius? If it is just a fun cruiser that you plan on putting your foot in it...that BBC should make enough torque you could run the 3:73...If I was going to run it in the 1/8 might lean toward the 4:11.