Rear Axle: Dana 27 Limited Slip Differential

[shanefausett]

I have a 63 Lark with a Dana 27 and a 3.07 gear ratio. I'm looking for a way to change this to a limited slip of some flavor. ( I live in Utah and snow is a thing here.) Any recommendations ?

[JoeHall]

The simplest approach would be to find a limited slip rear end and just do a swap. They're still fairly common, but 3.07 may be hardest ratio of find. You could go with another model 27, or a beefier model 44. But with a 44 you'd need new u'bolts for the larger OD axle tubes, and maybe have to shorten your driveshaft, since the 44's snout is 3/4" longer. But if you don't mind a bit of "yankee ingenuity" you could get by with your current driveshaft by offsetting the rear end perch center hole by 5/8" to move the 44 rearward that much. I say 5/8" because that's about max you can get by with. Been there - done that back in the day; another tech tip taught to me by Lester Schmidt (R.I.P.).

OTOH, if you have a six cylinder, a 44 may not be helpful, or even advisable.

[shanefausett]

I have a 5.3 LS V8. I drive her gently though.

[StudeRich]

This is a much more expensive option only for a Dana 44, but you would have to check with Randy's Ring and Pinion on the details and fit for a Studebaker, AND get a complete Model 44 Diff. with a worn out TT or a good "Open" Model 44 to convert to a Yukon Gear Limited Slip.

Quite expensive, but really Good is not cheap, at least it would be all new and guaranteed.
You would need the 19 Spline version, here is an example:

https://www.randysworldwide.com/products/ydgd44-3-30-1

[M-Webb]

Not cheap, but not horribly expensive for brand new modern stuff. I'm going to keep this in mind for my truck!

[skyway]

A friend who used to drive his two 185 OHV Studebakers pretty aggressively, blew the spider gears out of a couple of TT model 27’s, until he learned his lesson & went to 44’s.
His receipe was to be spinning the wheels on ice, snow (or even wet pavement), and then hit a dry spot. BANG!

[enjenjo]

Here you go. You don't even need to change the ring gear carrier.

https://www.ronsmachiningservice.net/lockers/dana/dana-27/dana-27-powertrax-lock-right-locker-10-spline/

[oilnsteel]

I have a brand new Dana 27 3.07 TT complete axle for sale here in Michigan. JT

[JoeHall]

I have a brand new Dana 27 3.07 TT complete axle for sale here in Michigan. JT

Shipping to the OP in Utah, by Greyhound, may be reasonable, if they'd accept it. But not sure if they would, due to oil concerns.

[maximus7001]

What does TT refer to?

[52DW2R5]

Twin Traction

[StudeRich]

Twin Traction

Note the Twin interlocking Circles with TT inside.
A Dana Limited Slip Differential, that Studebaker/Packard had back in 1956 in the Model 27 and 44 Dana !
I don't think Posi-Traction was available yet on GM Cars.

[M-Webb]

I need something like this for my Champ. Not for ice and snow, but you know, for other things. Currently it has just the standard D44 in it, but have a good 44TT to replace it with. But is only 4.27, same as what is in the truck now, a bit high, might want something a bit more highway friendly.

Not to hijack this thread, but can I convert the standard axle to TT and change the ratio with one of those modern replacement units above? If not on the standard rear, the TT I would assume is doable. Would be nice not to have to swap the whole rear though if don't need to.

I need to get my driveshaft altered soon for the trans swap. So if this rear end upgrade might affect that, ie different yoke or whatever, might be good to factor that in now before I do that. Not have to get the driveshaft modified yet again when get to that.

[JoeHall]

I need something like this for my Champ. Not for ice and snow, but you know, for other things. Currently it has just the standard D44 in it, but have a good 44TT to replace it with. But is only 4.27, same as what is in the truck now, a bit high, might want something a bit more highway friendly.

Not to hijack this thread, but can I convert the standard axle to TT and change the ratio with one of those modern replacement units above? If not on the standard rear, the TT I would assume is doable. Would be nice not to have to swap the whole rear though if don't need to.

I need to get my driveshaft altered soon for the trans swap. So if this rear end upgrade might affect that, ie different yoke or whatever, might be good to factor that in now before I do that. Not have to get the driveshaft modified yet again when get to that.

Yes, it is wise to choose the rear end before having a driveshaft made, for example the model 27 snout is 3/4" shorter than the model 44, meaning the distance between the transmission yoke and rear end yoke is 3/4" different. If your transmission has a fixed yoke, you will need a driveshaft with floating front yoke, which is quite expensive, so you wanna get it right the first time. Btw, it's cheaper to get a driveshaft shortened, but to get it lengthened it's about same price as a new one.

As for 4.27 rear gears, they would turn your truck into a farm implement, unless the transmission is an OD, which would make final output ratio closer to 3.0 - 3.1 which is OK for modern roads, but just OK.

[Rick P]

I have a Dana 27 with 3.73 gears coming out of my 1962 Hawk. I'm just south of you in the Phoenix area. Rick

[jackb]

27 vs. 44 vs. flanged vs. 8-inch ...... How do you expect to drive the vehicle ? I've never encountered a blown 27, but I drive like 1960, not 2025. Maybe I've been lucky buying non-abused cars/trucks. I can with some authority of driving Studes for over 40 years in New England winters tell you the TT is no better than an open R/A unless you've got 200+ lbs in the trunk. More important in the longer wheelbase Hawks. There's no weight out back for real traction and especially so for an empty truck bed. Get you a good pair of snow tires with or without steel studs, and the weight, and go "almost" anywhere the 4WD stuff goes. That's my current set up in my 62' Lark. Travels to Maine 5-6times a year in much snow...