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| Esoteric yet critical 8 1/4 axle housing question https://slantsix.org/forum/viewtopic.php?t=56860 |
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| Author: | Reed [ Wed Jan 07, 2015 7:02 am ] |
| Post subject: | |
Yes. I wonder if it was the super high 2.2/2.4 gear ratio cases that had the different offset. Unless everyone with an 8 1/4 is wiling to take some careful measurements, I don't think we will ever know. I just hope I can get this axle working. |
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| Author: | DusterIdiot [ Wed Jan 07, 2015 6:28 pm ] |
| Post subject: | So... |
What year Truck was donor for the other gears? According to various parts manuals, some online articles, and bearing guides... There are a few generational differences in the adjusters and bearings... For the 70's, the carrier from 2.2 to 2.56 will be different than the carrier for the 2.71 to 4.11 stock diff (and aftermarket gears could be had up to 5.30 at one time)...the A-body rear axle housing didn't change between 1973 and 1976 when it was offered no matter the ratio (2.45 in 318 cars up to 3.23/3.55 in the 73-75 cars, and limited to 2.94 in 1976). I have an 8 1/4" rear out of a 1972 dated Duster (1973 model year) with the 2.56 gears, the housing and most of the guts are exactly like the 1976 2.94 gear rear I have... the carrier is different and offset is like Reed's picture...this rear will eventually get a set of 3.91's and one version of sure grip or locker. There is a bearing change in 1972, trucks/vans received a different bearings and adjusters from 1972-1975 so if you use their carrier and gears you will need those bearings and adjusters specifically, there also is a change in the spider gears in these years and the factory specified to never use spider gears from 72-75 in the later diffs...Another few changes occured in 1976 and mostly remained until they changed the axle splines to 29 in 1997... Food for thought instead of wild speculation... ...and I've taken apart a GM 8.5 that had 3.31 gears and nothing in it is compatible with the mopar 8.25... but in a heated junkyard inspection with a big pile of rear ends it could be mistaken for the FMJ mopar unit... |
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| Author: | Reed [ Wed Jan 07, 2015 9:13 pm ] |
| Post subject: | |
Hmmm, interesting. The donor axle was definitely an 8 1/4. I purchsed the guts from Neil when he was working at Wildcat. I pulled the guts myself. I was told the axle was out of an early 70s B series van. Now that you mention it, I saved the adjusters from the donor axle and they are different from the adjusters in the Duster axle. I haven't measured thicknesses, but I do know that the donor adjusters do not have the adjysted hex in the middle. The donor adjusters have a smooth circle in the middle and would be adjusted with the factory tool that fit into the holes in the outer edge of the adjuster face. I will do some measuring while I have the adjusters out. |
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| Author: | slantzilla [ Wed Jan 07, 2015 10:00 pm ] |
| Post subject: | |
My experience was that trucks have larger diameter carrier bearings, but the carrier itself was the same. I have a SG unit at the shop that is out of a truck. I will be going down there Saturday afternoon if you need any measurements off of it. |
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| Author: | DusterIdiot [ Thu Jan 08, 2015 5:18 am ] |
| Post subject: | Did you see this article? |
http://www.hotrod.com/how-to/transmissi ... d-install/ |
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| Author: | Reed [ Thu Jan 08, 2015 5:33 am ] |
| Post subject: | |
I hadn't seen that article, thanks! I checked and the 2.2 and 3.5 carriers had the same bearings installed. I suppose it is possible that someone changed the bearings in the 40 years since the axles were manufactured, but the 3.5 carrier bearings looked pretty original. |
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| Author: | Reed [ Thu Jan 08, 2015 6:34 am ] |
| Post subject: | |
Oh, crap. I just read that article and reaized that I forgot to lube the pinion bearings before I assembled it and did all the pinion bearing preloa adjustments and installed the oil seal in the snout of the axle housing. Can I count on gear oil working its way up to the pinion bearings or do I need to pull it all apart, lube the pinion bearings, and start over again. I think I know the answer...... 
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| Author: | Joshie225 [ Thu Jan 08, 2015 10:47 am ] |
| Post subject: | |
Point the housing pinion down and you can get lube into the bearings, but if you didn't lube the seal it may not last long. |
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| Author: | Reed [ Thu Jan 08, 2015 11:05 am ] |
| Post subject: | |
Thanks Josh. I wasn't a total idiot- I did lube the seal. Looks like I need to unbolt the housing from the leaf springs when it comes time to fill it up with lube. |
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| Author: | sandy in BC [ Thu Jan 08, 2015 11:07 am ] |
| Post subject: | |
Overfill then drain the excess...... |
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| Author: | Reed [ Thu Jan 08, 2015 11:47 am ] |
| Post subject: | |
Quote: Overfill then drain the excess......
I like it! I might try that instead. This car won't be driven, so maybe if I overfill, put the plug in, and let it sit for a few months the lube will work its way down into the pinion bearings.
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