Dodge truck rear axles

[Kern Dog]

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?

 

[captainchrysler]

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.

 

[69DodgeMan]

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.

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?

 

[Kern Dog]

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.

 

[Max1196]

FYI, the 8 3/8 axle used in a van is about 2 inches wider than the truck axle.

 

[69DodgeMan]

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.

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.

 

[captainchrysler]

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?

It is an 8 3/8. That IS NOT a typo!!!! There are NO OTHER errors in my first post either.

 

[Kern Dog]

Put a tape measure on the ring gear if you're willing to disassemble the axle!

 

[69DodgeMan]

It is an 8 3/8. That IS NOT a typo!!!! There are NO OTHER errors in my first post either.

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.

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.

 

[Kern Dog]

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.

 

[69DodgeMan]

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.

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.

 

[7mopar]

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.

 

[cudamark]

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.

 

[Kern Dog]

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.