Rear Axle: Dana 44 Differential Ratio Recommendations

[wdills]

I am considering a gear change to make my Hawk a little better to drive. With the current set-up it is a little anemic at normal driving speeds. My current drive line is a 259, T86 O/D, and Dana 44 with a 3.31 ratio. It will run 70 mph at about 2000 rpm but it bogs easily on hills and is not very happy about taking off. I am thinking a different rear gear might wake it up a little. I know I would end up turning more rpm on the interstate, but I very seldom take it on the interstate.

So, my question is, what would be a good rear gear ratio for this set-up. I am not looking for a hot rod, I just want it to take off better and not have to shift at every hill I come to. That being said, I also don't want it to be screaming when I do take it on the interstate.

I guess another obvious question is, what is the sweet rpm range for a 259? Meaning what is the best torque vs. rpm range.

[rusty nut garage]

I am considering a gear change to make my Hawk a little better to drive. With the current set-up it is a little anemic at normal driving speeds. My current drive line is a 259, T86 O/D, and Dana 44 with a 3.31 ratio. It will run 70 mph at about 2000 rpm but it bogs easily on hills and is not very happy about taking off. I am thinking a different rear gear might wake it up a little. I know I would end up turning more rpm on the interstate, but I very seldom take it on the interstate.

So, my question is, what would be a good rear gear ratio for this set-up. I am not looking for a hot rod, I just want it to take off better and not have to shift at every hill I come to. That being said, I also don't want it to be screaming when I do take it on the interstate.

I guess another obvious question is, what is the sweet rpm range for a 259? Meaning what is the best torque vs. rpm range.

3.73 minimum. With the 259vs the 289 I'd personally go for 3.90. Many today will disagree but if you look at how the OD cars were built originally you'll go for a steep ratio.

[Hawkowner]

During my mis spent youth I pulled the automatic out of my 53 hardtop and put in a 3 speed over drive left the 3.5? Rear axle. With stock engine it would run faster in second and over drive than in high gear. Then I installed a 362 cubic in Buick.
and 3 speed Cad manual . Then tried to go drag racing and I puled the reared out of a 54 Studebaker station wagon that had a 3 speed OD and I forgotten the ratio but it was close to 4.0 had great acceleration.
With the overdrive I would look for a 3:90 or 4:10

[Mike Van Veghten]

Agreed, with your overdrive, an absolute minimum of 3.73, or lower.
I put a 3.90 gear in my daily driver 54 wagon with the T-200-4R trans.

Mike

[wdills]

I see that Summit Racing and others have gears for Dana 44's. Most of the references I see are to Jeeps. Is there anything special about the Stude set-up or can I just buy a gear set from Summit?

[Skybolt]

Most Studebakers I have driven used the 3.31 ratio and a 1:1 transmission. These always lacked a nice highway cruse and felt like another gear would make it the best of both worlds but it doesn't work out that way. Haven driven my 59 Lark with a 170 six and 3.54, a OHV six with a 4.10, and now installing a 3.73, with a 259, I have found what I call a good compromise. I am using an overdrive transmission that will give me good acceleration through to the 1:1 top and when in OD it should knock the RPM down about 1000 and give it a literal rear ratio of about 2.985:1. It could be that a 3.54 might be better but at this point and I could also change tire diameter when it comes time for new rubber, to tweak it up or down.

Many years ago I spoke with a guy running salt flat cars. He was going for top speed, obviously, but he, through experience, found that what works on paper does not translate to the ground, where the rubber meets the road. He found that by numerically increasing the number of his differential he could actually have a higher top speed. His taller, numerically lower, ratio would not allow his engine to maintain or pull through it's torque curve to reach it's top power. Dropping the ultimate numbers on paper increased his top speed as the numbers were now attainable.

Best bet 3.54 or 3.73

Len

[StudeNorm]

I believe if you are just thinking about changing the gear set you are limited to the 3.73 gears. The next set up (3.90) will not fit your case. There are two cases for the Dana 44 and the breakpoint is, I think, 3.73:1. I am sure someone can help you out with getting the larger case if you decide to go that way.

[Treblig]

I'd would go with 3:90s. That's what I'm putting in the '59 Silver Hawk (2004R overdrive auto).

Treblig

[PackardV8]

Since Dana 44s are still thick on the ground, decide what gear ratio you want and shop for a complete assembly. It's usually much more cost-effective than building one.

You asked about the RPM sweet spot for the 259". According to the charts published by Studebaker Engineering, the torque curve is relatively flat between 2250 and 3750. Where you choose to cruise depends on your tolerance for the occasional downshift. Those of us who like to fiddle with the machinery will wire a supplemental switch so as to be able to manually downshift out of overdrive at part throttle, thus enabling using a taller gear. Those who don't want to be bothered will want lower gears and accept more RPM at cruise.

FWIW, even with the massive torque of the Packard V8, for the '56Js with overdrive, they chose to use a 3.90 gear. With a T86, that would give an overall of 2.73, as tall as a 259" can pull up a hill; so consider the 3.90 or 4.10. Either of those would really wake up your ride.

jack vines

[Studebakercenteroforegon]

In my younger days I had a '57 Silver Hawk with a straight 3 speed transmission and a 3.54 rear axle ratio. I swapped in an overdrive transmission with a "jeep top" shifter and just used a toggle switch to engage the overdrive solenoid. This was a nice combination for cruising on the freeways, yet simple to kick down to direct if climbing a long hill.

[Treblig]

Would any of these work??

http://www.wfoconcepts.com/pr/8-8-Explorer-rear-axles/3166/10262

treblig

[wdills]

I have thought about adding a switch to kill the overdrive when I'm not on the interstate. But that won't help it taking off from a stop. Right now, it is easier to take off in dad's 50 champion with a tired 170. Of course he has a 4.55 rear and you have to shift to second at about 15 mph.

I may just pull the OD fuse and drive around a bit to see how I like the response before I start buying stuff.

[rstrasser]

Wdills;
There should be a lever under the left side of your dash board that when it is pulled out; it locks out the overdrive. There should not be any reason to pull a fuse. Also unless it was modified there is a governor on the overdrive unit that prevents going into overdrive until 20 plus miles is reached.

As for what ratio to run. My 55 with a 259 had a 3.90 rear end from the factory and I found it about ideal. Low RPMs on the highway and plenty of power for hills. With a switch replacing the Governor; switching between either 2nd or 3td overdrive to direct drive was very easy. if in traffic one could start off in 2nd and then go to 2nd overdrive or leave leave the lever in and the switch off and shift without the clutch. No engine breaking of course.
Ron

[GrumpyOne]

I am considering a gear change to make my Hawk a little better to drive. With the current set-up it is a little anemic at normal driving speeds. My current drive line is a 259, T86 O/D, and Dana 44 with a 3.31 ratio. It will run 70 mph at about 2000 rpm but it bogs easily on hills and is not very happy about taking off. I am thinking a different rear gear might wake it up a little. I know I would end up turning more rpm on the interstate, but I very seldom take it on the interstate.

So, my question is, what would be a good rear gear ratio for this set-up. I am not looking for a hot rod, I just want it to take off better and not have to shift at every hill I come to. That being said, I also don't want it to be screaming when I do take it on the interstate.

I guess another obvious question is, what is the sweet rpm range for a 259? Meaning what is the best torque vs. rpm range.

3.31 is way to tall for an OD car for normal driveability. My Power Hawk has a 3.9x rear with 3 speed/OD. I find it very acceptable with tons of pep out of OD and when in OD for the long haul... 2,000 RPM at 60mph. Also economy in the range of 25mpg for those distant meets...

[JoeHall]

With the 259, I'd suggest a 3.73 or 3.54. With 205/75 tires, and a 3.73, the car will be moving around 74-75 MPH at 2500 RPM, in third OD. With a 3.54, it will be moving 77-78 MPH. It will move along just fine on the road, and seldom need to kick down, with either of those rear end ratios.

Sounds like you could be getting a lot more out of the OD than you realize. It is extremely versatile. In addition to the other suggestions above, you can adjust the governor to kick in lower, at say 2200-2400 RPM, instead of 2800-3000. That makes for much less manual shifting around town, since 2nd OD is then so much easier to engage. You can always kick it out of OD with a flick of the gas pedal.