I have a 7 1/4 rear end with broken spider gears out of a 73 dart which has the large lug bolt pattern. I also have a 7 1/4 with the small bolt pattern. I need to know can I just change the spider gears from one to the other will they interchange. Can I do this with out pulling the hole third member out of the housing Also one is a sure grip the other isn't. Thanks
how to spider gears
- Thread starter bmiker
- Start date
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motorpirate
serial mopar owner
I don't think an open diff shares any parts with a sure grip.If the sure grip is in your "parts" diff, just change the ring gear and reset the backlash.Your pinion depth is already set up as you aren't changing pinions.If that doesn't make sense sell me your suregrip!!!(I have a good 7 1/4 open diff and a new set of spiders in stock)
torquehouse
Well-Known Member
You can't just change the ring gear. Ring and pinion gearsets are a matched set. They are run-in together at manufacture. If you mix ring and pinion, one or more of the following will result: (1) Inability to obtain a good wear pattern, (2) Noisy operation, (3) Premature wear/failure. Don't mix parts. Repair or replace one or the other.
grumpuscreature
Resident Curmudgeon
If I read this correctly and you are wanting to keep the large bolt pattern, just swap the axles and brakes. That's all that needs to happen.
motorpirate
serial mopar owner
First, I didn't say to switch the ring gears,but to switch the actual diff assy,keeping the ring and pinion together as a set.
second the bolt pattern on the LBP backing plate/bearing is larger than the SBP.LBP axle tubes flare out to the same size as a 8 1/4 right at the end so they can use the same brake assy.
second the bolt pattern on the LBP backing plate/bearing is larger than the SBP.LBP axle tubes flare out to the same size as a 8 1/4 right at the end so they can use the same brake assy.
torquehouse
Well-Known Member
A 7 1/4 rear axle is a rear-loader axle. Unlike the 8 3/4 rear, the pinion remains in the housing when you remove the carrier assembly. It all comes out through the rear of the housing, after you remove the rear cover. No quick fix here.
motorpirate
serial mopar owner
no,the LBP axles are shorter by about an inch than the SBP.
I learned this all the hard way changing my '66 cuda to LBP about 4 Mos. ago.
However all the internals are the same.That is why I said you could change your 3rd member between housings by only re setting the backlash.
But you must keep the ring/pinion together as a set.
The spiders can be replaced withought removing the 3rd member from the housing.I assume your "open' diff is the broken one?(earlier offer was serious)
I learned this all the hard way changing my '66 cuda to LBP about 4 Mos. ago.
However all the internals are the same.That is why I said you could change your 3rd member between housings by only re setting the backlash.
But you must keep the ring/pinion together as a set.
The spiders can be replaced withought removing the 3rd member from the housing.I assume your "open' diff is the broken one?(earlier offer was serious)
Thanks for the info.Your help will save me some of that hard way learning.
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