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Hey, haven't been here in awhile and to be honest, just happened upon an older discussion about the Dana rears. Spring of '22 I rebuilt the motor to nearly 500hp. I had the trans (t-350) built the previous fall in preparation. I built it mostly old school, 1970 492 casting LT-1 fuelie heads, nice cam, Air gap manifold with 650 Holly, .040 bore, decked, tru compression 10.7-1. I broke her in easy, then when I felt it was ready, I let her rip. This by sheer coincidence happened to be on a freshly re-paved hiway and when 2nd banged I literally twisted the right half shaft like a pretzel. Thus began all my problems with the rear, which I admittedly don't know a whole lot about, except new ways to break em. Something is happening now I can't figure out. When I get even moderately into it all of the sudden feels as if a tire or something was rubbing hard, throws the car all squirly, and makes a sound like its dragging a wheel. I let off gas and it's normal. No witness marks anywhere on rims, tires, shafts, anywhere to be found. Oh yeah, it will make the same noise occasionly when I make a right turn from a stop. I'm about to have the rear re-sealed and re-geared, I just don't know whats going on and want to know so I can make an informed decision on my next move. Thanks.
The Dana was not designed to handle that much HP. A much better choice is to (properly) build an “iron” unit as they are inherently stronger and it is a straightforward conversion to install. The “iron” differentials were installed from 63-79 but you want to avoid the early ones. If you want to consider that option further, there is an extensive library of posts on this forum (particularly those from Gary Ramadei (GTR1999) who is the resident expert on them) on what is needed.
That said, most everything in the driveline is subject to breakage from a hard hookup as you have described.
The Dana was not designed to handle that much HP. A much better choice is to (properly) build an “iron” unit as they are inherently stronger band it is a straightforward conversion to install. The “iron” differentials were installed from 63-79 but you want to avoid the early ones. If you want to consider that option further, there is an extensive library of posts on this forum (particularly those from Gary Ramadei (GTR1999) who is the resident expert on them) on what is needed.
That said, most everything in the driveline is subject to breakage from a hard hookup as you have described.
Not knowing any better of the interchangeability of older, tougher units, I've been upgrading the parts as I break em. The half shafts are almost twice as thick now. I twisted up that camber rod and adjustment system so now has the thicker, adjustables. Spring mount bushings and bolts are upgraded, fabricated a carrier plate using 1/4 steel. It leaks pretty good now from being twisted up. Front diff. bushings are shot, and with the Dana's the rear has to be lowered to change it anyway. Things that bother me are the things that I don't know why are happening, like the situation I originally described, and I have to constantly replace one of the u-joints on the half shaft, always the drivers side at the punkin, at least once a month. I'm wondering if that's an angle thing due to bad bushings? Thanks for any help...
As mentioned before, dropping that much force in an instant is going to expose you to breaking something. The driveline is like a chain, you beef up one of the links, only to see another fail and short of building out a 4 link with a 9” Ford differential, you’ll be at risk of scraping up the pieces every time you drop the hammer.
It is a bit of a long shot but you could see if you could locate one of Tom’s differentials, 1480 U-joint shafts and his Kick-*** axles. Tom passed a few years ago and finding a used setup is hard but I have seen them pop up on this forum. The Tom’s differential is an iron unit.
Thanks for the help. I had the car about 3 feet off the ground crawling around looking for any rub or witness marks, the only thing I found was a stripped bolt on the upper right side of the casing. I sent it off to a place called INGear Transmission and Rear in Wall TWP NJ. before I could do any more damage, They haven't opened it yet, Hoping for the best, and I'm going to change gear ratio to the 3.54's. I'd rather burn rubber then break things.
Dana 44 Symptoms and problems
