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John-M
Dodge Dakota
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8/19/2007
12:26:00
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 Subject: 8 1/4" rear Sure Grip?
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I haven't had much luck with this question over at Moparts so I will try here.
I have a 74 Duster which has an open 8 1/4" rear end. Someone told me I could use the insides of an 8 1/4" Dakota Sure Grip on my Duster. Is this true, and if so, what years would match my car? Thanks for your help.
John
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Kowalski
GenIII
8/19/2007
12:42:19
| RE: 8 1/4" rear Sure Grip?
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I don't believe that's correct - I'm just about positive the axles have a different spline count. I think there are other differences as well. The popular mod used to be to get the stronger 8 3/4 rear from an earlier A-body (Dart, pre '70 Barracuda, etc.); then get axles with a 4 1/2" bolt pattern from somplace like Moser to match your wheels. The earlier A-bodies with the stronger rear had a smaller 4" bolt pattern.
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John-M
Dodge Dakota
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8/19/2007
20:02:34
| RE: 8 1/4" rear Sure Grip?
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Apparently they are interchangeable up to the '97 model year - according to a person on Moparts.
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Kowalski
GenIII
8/20/2007
17:14:35
|  RE: 8 1/4" rear Sure Grip?
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I wouldn't bet on it. In fact, I'd bet against it.
That's according to me; not some anonymous source.
Always consider the source...
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Kowalski
GenIII
8/20/2007
18:40:25
| RE: 8 1/4" rear Sure Grip?
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Did some looking around - my bad on the spline count. Both should be 27. From years ago, when I had an F-body Road Runner with the 8 1/4 though, I remember there was supposed to be some incompatibility between the older 8 1/4s and the newer ones. Might want to look into it further...
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John-M
Dodge Dakota
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8/21/2007
01:29:37
| RE: 8 1/4" rear Sure Grip?
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Here are 3 responses from different people on the Moparts BBS:
1. I know there is a difference between Early and Late Carrier Bearings, but you should have no problem using it with the correct bearings.
2. I have a '93 Dakota that I wanted a suregrip in. I located a 8 1/4 suregrip out of an aspen and just used the center section..I even installed the antilock ring...So the answer to your question is yes the parts are swappable...
3. The Sure Grip unit from the truck will need to be '97-down. Axle spline count changed in '98.
Some trucks also used the 8.375 rear but I think the carrier will swap into a 8.25.
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Kowalski
GenIII
8/21/2007
15:27:37
| RE: 8 1/4" rear Sure Grip?
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I belive you mean 8.75 rear, and that's a completely different design - the pig drops out of the front of the diff. Back is solid, no back cover. That's the stronger rear I tried to steer you toward in my first post; and it's nice because you can just back the axles out to change ratios if you have another pig set up. Just have to reset the axle end play after swapping, with no need to set the gears up all over again when you swap. I don't believe there is a 8.375 mopar rear.
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Hollis
Dodge Dakota
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8/21/2007
20:41:45
| RE: 8 1/4" rear Sure Grip?
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Kowalski knows about some rear ends! :)
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gen1dak
Dodge Dakota
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8/21/2007
21:31:38
| RE: 8 1/4" rear Sure Grip?
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Yeah, but as I have seen on occasion, there's always more to learn. Take, for instance, the reference to the 8.375 Mopar rear. No, that's not a mistake, or a typo. It's an 8 3/8" ring gear. It interchanges with the standard 8.25 ring gear. Just a bit heavier. They were used in trucks....including the '89 Shelby Dakotas. Their 8 1/4 rears had 3.90 ratio with 8.375" ring gears.
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b1llyw
GenIII
8/22/2007
20:13:45
| RE: 8 1/4" rear Sure Grip?
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I am selling a new Auburn limited slip for an 8.25 rear, 96 and earlier, 27-spline. Looking for $275 + shipping. Box is 12x12x12, 25 pounds, shipping from 06385.
Bill White - KRC Performance
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Kowalski
GenIII
8/23/2007
08:03:22
|  RE: 8 1/4" rear Sure Grip?
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Thanks, gen1, for clearing that up. So it's the same rear, with a heavier gear, since the 8 1/4 is a weaker unit. They didn't have to do anything like that with the 8.75 rears, I've tried to steer clear of the weaker sizes.
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gen1dak
Dodge Dakota
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8/23/2007
16:23:38
| RE: 8 1/4" rear Sure Grip?
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One of those quiet little things they did for some reason. I mean, it's not like the standard 8 1/4 has a bad rep for broken ring gears (that may be partly due to the fact that so many would automatically swap in an 8 3/4 for performance uses). I wouldn't have even known about it had I not been inquiring several years ago about alternate gearing. Hard to go wrong with the 8 3/4 for all but the heaviest needs. Nothing better for easy gear swaps. I mean, fellows would actually drive to the dragstrip, swap gears in less than an hour, race, then swap gears again to drive home. Try that with any of the other rears Mopar has offered, or the other companies, for that matter. Only a select few can make that claim, and none are as enduring as the 8 3/4.
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John-M
Dodge Dakota
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8/24/2007
12:54:22
| RE: 8 1/4" rear Sure Grip?
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I didn't say in my opening post that I already have an 8 3/4 rear end sitting in another car my yard because I have explored the option of removing the 8 1/4 from the Duster and replacing it with the 8 3/4. I have the smaller 741 8 3/4" unit. From what I have learned the 8 1/4 Sure-Grip may be as good an option for me as the small 8 3/4, not to mention the 8 1/4 is more readily available and maybe half the cost.
That's why I asked here if anyone knew which years of Dakota rear ends might fit the Duster.
When I said that a person on Moparts told me that he knew that the 8 1/4 rears were interchangeable from the 74 Duster to the 97 Dakota, Kowalski said it all when he said "I wouldn't bet on it. In fact, I'd bet against it. That's according to me; not some anonymous source.
Always consider the source..."
I always do try to consider the source like he says but lo and behold Kowalski wasn't exactly correct so if I had considered his word as final I'd have made a mistake and listened to the wrong advice.
So there are a few lessons to learn. Always consider the source. Always seek several opinions. And never shoot down the other guy's opinion or facts until you do some thorough research.
There is a wealth of knowledge on the internet and especially on web sites like moparts.org and www.dodgedakotas.com but everyone, no matter how expert they are, can make a mistake. Always consider the source AND always ask for a second and thrid opinion.
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gen1dak
Dodge Dakota
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8/24/2007
13:22:15
| RE: 8 1/4" rear Sure Grip?
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Or you could just RTFSM.
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Super bee
GenI
8/24/2007
14:08:24
| RE: 8 1/4" rear Sure Grip?
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could it be that the pitch and tooth count on the 8 1/4 don't work out and you need the extra 1/8" to get the tooth count right for the ratio?
1990 sport RC SB, 1995 318drivetrain, 3.92 gears (came with truck) Powertrax "traction system", 95 dash/steering wheel, hearthrob exhaust, headers, cutout after y-pipe, necessary electric fan add-a-leafs, 30x9.5 mud tires, cranked T-bars, AR 39 15x8 rims, grill guard, roll bars
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Kowalski
GenIII
8/27/2007
09:03:26
|  RE: 8 1/4" rear Sure Grip?
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Looking to run some fairly deep gears ? Isn't the 741 case 8.75 much stronger than the 8.25; but just not sized for the deepest ratios ? The 8.75 is a much better rear. If you do the 8.25 guts swap, maybe you could let the guys with the 8.25s know if it actually works out.
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