Drivetrain Measurements and Drive Shaft Lengths

adman02

Basic User
City
Durham
State
nc
#1
I have an 83 Scrambler (Iron Duke, T176/D300) and have two questions:

Drivetrain: I pulled the engine and replaced it with an AMC 304 today. I have the proper frame horns, but realized that I have to move the entire drive train back approximately one inch for the motor mounts and frame horns to line up. Is this common? Seems so because there are three sets of holes in the skid plate for the transmission mount bolts.

Drive Shaft Lengths: because of the issue above, my front shaft is now too short and I think the rear will be too long. I'd like to see if there are other stock drive shafts that will fit my new setup (304, T176/D300) before getting custom shafts made. Any idea what shafts/lengths would fit? And how do I measure drive shafts - compressed, extended, something else?
 

walkerhoundvm

Just trying to stay upright
LIFETIME
CJ-8.com Member
City
Cave Creek
State
AZ
#2
Drive shafts are not prohibitively expensive, really. About $500 for a good solid pair from Tom Woods (including U-joints and straps), and delivered within 7-10 days. You would measure from mounting tab to mounting tab. There are instructions on their website, and if they're not good enough you can give them a call.

You can certainly do the measurements and hunt on ebay or forums for what you need, but it might be a more effective use of your time and money to just order a new set.
 

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#3
A local driveline shop can do this for you as well.

Once you get the transfer case in place, measure the yoke to yoke distance for each drive shaft, and the shop will take it from there. :thumbsup:
 

Spieg

Scrambler Junkie
LIFETIME
CJ-8.com Member
City
Aurora
State
CO
#4
Scramblers never came with a V8 so you probably wont find a stock replacement to fit. A drive line shop can shorten the existing rear shaft pretty easy to save you a little $, but the front will require a new shaft (the OEM front shaft is pretty slim, so I'd get something a little beefier while you're at it).
 
Last edited:

CJ7Pilot

18436572
LIFETIME
CJ-8.com Member
City
Yuba City
State
CA
#5
I've read in a few places that the 304 was an option in 1981... but I've never seen a Scrambler in person or online with a "factory" 304. :shrug:

Even if a few of them were produced, finding a junked one for the drive shafts would be next to impossible.
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
#8
I have an 83 Scrambler (Iron Duke, T176/D300) and have two questions:
Drive Shaft Lengths: because of the issue above, my front shaft is now too short and I think the rear will be too long. I'd like to see if there are other stock drive shafts that will fit my new setup (304, T176/D300) before getting custom shafts made. Any idea what shafts/lengths would fit? And how do I measure drive shafts - compressed, extended, something else?
Theoretically, the drive shafts from an '83 Scrambler with a 258/T176/D300 combo would be the same as the 304/T176/D300.
Typically drive shafts are measured in the compressed position.
Your existing driveshafts should be:
Front ~ 27-1/4"
Rear ~ 36-1/8"

If you can confirm the measurements of yours, and how/where you measured to-from, I can do the same with my 258/T176/D300 shafts.

Again, this is based on information from available online charts, not actual experience.
 

adman02

Basic User
City
Durham
State
nc
#9
Theoretically, the drive shafts from an '83 Scrambler with a 258/T176/D300 combo would be the same as the 304/T176/D300.
Typically drive shafts are measured in the compressed position.
Your existing driveshafts should be:
Front ~ 27-1/4"
Rear ~ 36-1/8"

If you can confirm the measurements of yours, and how/where you measured to-from, I can do the same with my 258/T176/D300 shafts.

Again, this is based on information from available online charts, not actual experience.
I was wondering if the L6 and 304 had similar lengths. I'll pull and measure the shafts in the next few days and I'll report back. Thanks for the help FLCJ8 and everyone else.
 

adman02

Basic User
City
Durham
State
nc
#10
Ok. Pulled the shafts today.

The collapsed driveshafts measure from outside of yoke ear to outside of yoke ear (basically end to end)
• front - 28 3/4 in.
• rear - 37 1/2 in.
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
#11
Ok. Pulled the shafts today.

The collapsed driveshafts measure from outside of yoke ear to outside of yoke ear (basically end to end)
• front - 28 3/4 in.
• rear - 37 1/2 in.
Okay,
I'll try to get similar measurements of mine tomorrow.
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
#12
Ok. Pulled the shafts today.

The collapsed driveshafts measure from outside of yoke ear to outside of yoke ear (basically end to end)
• front - 28 3/4 in.
• rear - 37 1/2 in.
Hey, I didn't forget about you. It's been dark when I finally get home.
I'll get out there tomorrow.
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
#14
Okay, I got some numbers for you.
First off, typically if purchasing a stock replacement driveshaft they are listed as collapsed length from center- center of yoke.
The measurements you took on your factory shafts would be consistent with those lengths.

I took measurements of my shafts using the same method as you:

Collapsed
Front ~31"
Rear ~34-3/8"

On Vehicle
Front ~32-5/8"
Rear ~36-1/4"

Here is a pic of my 8 for reference, the springs are a "Frankenstein" of various springs to get it level and allow tire clearance.
Also, it has an additional 1" body lift for tire clearance that obviously doesn't affect the driveline. Lift.jpg
 

adman02

Basic User
City
Durham
State
nc
#15
Thanks, FLCJ8, for taking those measurements. I forgot to post the "as it sits", "before moving the drivetrain back an inch" measurements between the yoke faces:
Front: 28 1/4
Rear: 37 3/8

I'm starting to think that it might be easier just to buy new custom shafts, especially since I don't know how much allowance to leave for shaft compression/movement. Plus, I intend to put a lift on it next. That said, it seems reasonable that a front drive shaft from a 258/T176/300 combo could work. Not sure about the rear shaft though.
 

sdsupilot

CJ-8 Member
CJ-8.com Member
City
OKC
State
OK
#16
I took these off during my engine swap. I don’t know why my measurements were so far off the others mentioned. These were off an 81 with a 258, SR4 and Dana 300. The 258 was a swap, originally a GM 4 cyl. It has since returned to its gm roots with a 4.3 v6. I bought new shafts from Tom Woods.

If anyone wants them I would sell them for $50 for the pair. But if these are odd lengths, they may not be worth the effort.

E4CE2518-0644-47EE-BE03-055A8922F18B.jpeg
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
#17
Thanks, FLCJ8, for taking those measurements. I forgot to post the "as it sits", "before moving the drivetrain back an inch" measurements between the yoke faces:
Front: 28 1/4
Rear: 37 3/8

I'm starting to think that it might be easier just to buy new custom shafts, especially since I don't know how much allowance to leave for shaft compression/movement. Plus, I intend to put a lift on it next. That said, it seems reasonable that a front drive shaft from a 258/T176/300 combo could work. Not sure about the rear shaft though.
All things being equal, if the front is correct the rear would be as well since the shafts run from the D300 to each axle.

I agree that custom would be better as the stock shafts were not designed for a lift.
As you said they know how much allowance to design for. Once you have everything complete they can make you true custom shafts.
Also, I've had new shafts made locally for a friend's 8 and they reworked the rear for the front. It is a little beefier and didn't have any clearance issues.
 
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