Hi all,
I am currently building up a couple of D-44 front axles one for me one for an acquaintance and I’m struggling between the nice low gearing of the 4.88’s and the strength of the 4.56’s.
The pinion on a 4.88 has 8 teeth, the 4.56 has 11 (I think). Both are high pinion designs, both will be run with 35” tires and low geared transmissions, both are behind 200 hp six cylinder motors (4.0 and 4.3 V-6). Both will have Moser shafts and upgraded u-joints (if Jesse ever finalizes his chromoly 297 joints). Both rigs are driven on the road, but not daily. And finally, both of us live in the mountains, where we rarely get into overdrive (but I would like to). Here’s what the RPM’s look like with 35” MTR’s (608 revolutions per mile) and a 27 % overdrive manual trans.
4.56: 55mph = 1983rpm 65mph = 2343rpm 75mph = 2703rpm
4.88: 55mph = 2132rpm 65mph = 2519rpm 75mph = 2907rpm
Thoughts, opinions? Is the difference in strength drastic, or not enough to worry about? On that note, how would you guys rank the R&P maufacturers? I've always used Dana stuff, but 4.88's are not available from them for my 8.8 Ford rear unit. How is Precision Gear?
If anyone has ever seen me drive, you would understand the need for every last ounce of strength I can get. Yes, I know I really need a shaved 60. They are scarcer than frog hair right now, and way too expensive, at the moment. I’ve also discarded my original plan of the high pinion 9 inch. Currie is WAY to proud of their center sections, I could have built a HP 60 for the same money (which i don't have)!
CRASH
I am currently building up a couple of D-44 front axles one for me one for an acquaintance and I’m struggling between the nice low gearing of the 4.88’s and the strength of the 4.56’s.
The pinion on a 4.88 has 8 teeth, the 4.56 has 11 (I think). Both are high pinion designs, both will be run with 35” tires and low geared transmissions, both are behind 200 hp six cylinder motors (4.0 and 4.3 V-6). Both will have Moser shafts and upgraded u-joints (if Jesse ever finalizes his chromoly 297 joints). Both rigs are driven on the road, but not daily. And finally, both of us live in the mountains, where we rarely get into overdrive (but I would like to). Here’s what the RPM’s look like with 35” MTR’s (608 revolutions per mile) and a 27 % overdrive manual trans.
4.56: 55mph = 1983rpm 65mph = 2343rpm 75mph = 2703rpm
4.88: 55mph = 2132rpm 65mph = 2519rpm 75mph = 2907rpm
Thoughts, opinions? Is the difference in strength drastic, or not enough to worry about? On that note, how would you guys rank the R&P maufacturers? I've always used Dana stuff, but 4.88's are not available from them for my 8.8 Ford rear unit. How is Precision Gear?
If anyone has ever seen me drive, you would understand the need for every last ounce of strength I can get. Yes, I know I really need a shaved 60. They are scarcer than frog hair right now, and way too expensive, at the moment. I’ve also discarded my original plan of the high pinion 9 inch. Currie is WAY to proud of their center sections, I could have built a HP 60 for the same money (which i don't have)!
CRASH
