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Dodge truck rear axles

Kern Dog

Kern Dog

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I'm a bit curious about the rear axles used in Dodge trucks from say....1970 until the early 90s.
Out here in California, I've owned several of these as well as being a junkyard crawler for years. It has been my experience that the 9 1/4" rear axle has been the most common unit used in the 1/2 ton and light duty 3/4 ton trucks.
The 3/4 tons with the higher GVWR stepped up to the Dana 60.
The 8 1/4" axle was also used though some refer to it as the 8 3/8" unit. I'll refer to it as the 8 1/4" for now.
It is my understanding that the 8 1/4" axle was used in 1/2 ton models only and not with any 400 or 440 powered trucks.
I've never seen an 8 1/4" axle in any 4 wheel drive truck. I've never seen one in any Ramcharger or Trail Duster.
I admit that I have not seen everything but some people at FABO seem to think that the 8 1/4" axle did come in 4wds, 440 powered trucks and 3/4 ton trucks, three things that I have never found in the many trucks I've seen over the years.
The 8 1/4" axle was a medium duty unit. MY own '70 Charger came with an 8 1/4" axle since the car was built with a 318. 383 2 barrel cars also got the 8 1/4" axle as standard equipment but the 383 4 barrel cars automatically got upgraded to the 8 3/4" so it would sure seem like if Ma Mopar didn't trust the 8 1/4" to a 3700 lb car with a 383 4 barrel, no way would they put this axle in a 3/4 ton truck.
5.9 equipped Durangos had the 9 1/4" unit and they are not 3/4 ton trucks.
What are your opinions on this?
 
The 8 3/8 (that's how Mpoar reefers to them in vans and pickups) was used with 400 trucks, 4WD and both combined. Ramcharghers got them too, 2WD and 4WD. And there was a version that was used in 3/4 and 1 ton vans in the 80's.

I've beat the living hell out of them with no issues ever.
 
captainchrysler said:
The 8 3/8 (that's how Mpoar reefers to them in vans and pickups) was used with 400 trucks, 4WD and both combined. Ramcharghers got them too, 2WD and 4WD. And there was a version that was used in 3/4 and 1 ton vans in the 80's.

I've beat the living hell out of them with no issues ever.
Click to expand...
60 years of owning, driving, wrenching on Mopars of all makes/models and I've never heard of an 8 3/8 rear differential. But then, considering all the other typo errors in your post, I guess what you really meant was an 8 3/4" rear?
 
There are references to an 8 3/8" axle in the factory service manuals. They are the same as the 8 1/4" axle but for some reason, they called them 8 3/8" in the trucks.
I've still never seen one of them behind a 440.
 
Kern Dog said:
There are references to an 8 3/8" axle in the factory service manuals. They are the same as the 8 1/4" axle but for some reason, they called them 8 3/8" in the trucks.
I've still never seen one of them behind a 440.
Click to expand...
Thanks for the clarification KD. When I had older Dodge trucks ('49, '53 '65, '72, & '87) I never had the service manuals for them so never heard about the so called 8 3/8" rear. Actually come to think of it, I do have a service manual for my '53 Dodge. I'll have to check out the section on the rear to see what it says.



My apologies to CC for doubting his post.
 
69DodgeMan said:
60 years of owning, driving, wrenching on Mopars of all makes/models and I've never heard of an 8 3/8 rear differential. But then, considering all the other typo errors in your post, I guess what you really meant was an 8 3/4" rear?
Click to expand...
It is an 8 3/8. That IS NOT a typo!!!! There are NO OTHER errors in my first post either.
 
captainchrysler said:
It is an 8 3/8. That IS NOT a typo!!!! There are NO OTHER errors in my first post either.
Click to expand...

OK, it must be me then. But can you please clarify what a "Mpoar reefers" is/means??

Also I'm wondering what a "Ramcharghers" might be??????????

Both are from your first post. But, whatever, you are correct about the 8 3/8", verified by KD. Thanks so much for the info.

captainchrysler said:
The 8 3/8 (that's how Mpoar reefers to them in vans and pickups) was used with 400 trucks, 4WD and both combined. Ramcharghers got them too, 2WD and 4WD. And there was a version that was used in 3/4 and 1 ton vans in the 80's.

I've beat the living hell out of them with no issues ever.
Click to expand...
 
Maybe the dude was posting from a phone and didn't look his post over before submitting?
I make the majority of my errors when doing that. Tiny screen, tiny buttons and 59 year old eyes! When I go back and see my spelling errors, I immediately correct them.
 
Kern Dog said:
Maybe the dude was posting from a phone and didn't look his post over before submitting?
I make the majority of my errors when doing that. Tiny screen, tiny buttons and 59 year old eyes! When I go back and see my spelling errors, I immediately correct them.
Click to expand...
I agree with you, I think that is probably the case with his post. (Either that, or too much sauce while posting??)

BUT, my whole point was that I thought he meant an 8 3/4 instead of the 8 3/8 that he posted. I thought his 8 3/8's statement was a typo based on the fact there are several other typo's in his post. (Which he then denied that there were any??)

I apologized to him once already, I won't do it twice. All done with this topic now. 👋
 
Here I thought we where all Mopar people.
I have never seen anything but a full floater in a 3/4 ton truck. Who in there right mind would want a light duty rear axle in a 3/4 ton truck? Must be those messed up city folk.
 
First lets eliminate the 3/4-1 ton pickup and 1 ton vans. Those were all 8 lug Dana 60's and 70's. The '70-1 D100's, and W100's were all 8 3/4 rears. '72-4 D100 could have had either the 8 3/4 or the 8 1/4. '72-4 W100 would have had an 8 3/4. From '74-up the D100's would have come with an 8 3/8 or 9 1/4 depending on engine size and other options requiring heavy duty or not (like a tow package, camper special, etc) The '74-up W100 were all 9 1/4. As for 8 1/4 (car) vs 8 3/8 (truck/van), the gear sets as a set would interchange and use the same housing and carrier. A series vans were all 8 3/4. B vans again could come with either 8 3/8 or 9 1/4 depending on needs just like the pickups. Oh, and for whatever reason, the '74 Ramcharger couldn't come with an 8 3/4 even though the W100 that year did. The Ramchargers/Traildusters were all 9 1/4 equipped 2WD or 4WD from '74-8. In '79 they could have either, like the pickups.
 
Thank you, Mark.
I am pretty sure that I've seen 8 lug 9 1/4" axles in the lighter duty 3/4 tons prior to the changeover in 1994.
I have no pictures or legitimate proof, I just recall seeing them when I was looking for parts for my 74 Camper 9000. That truck was a heavy duty rig. It had a dana 60 with floating axles and fat lugs, maybe 5/8" but probably 9/16". The rear brakes were unusual, I had a hard time finding drums and shoes for it. I remember seeing 9 1/4" axles in a few 3/4 ton trucks in junkyards and being surprised by it. I don't recall if they had floating axles or not but the housings had tubes that stepped down in size at some point.
Forgive me, the memory on this is a bit fuzzy.
 
My 1 ton has a Spiker 70. Yes call it a Dana but it's not. That's an 86 axle in an 83 chassis. Sometimes you just have to follow the parts.
 
Are you sure it is not a "Spicer" and not a Spiker?
I know that Dana and Spicer had a business partnership for awhile.
 
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