What Diffs Will Fit Under Stock Frame?

[LameNytro]

hey everyone, its been awhile since ive been on here, and let alone worked on my truck.  I was wondering if any later model dodge diffs will fit under the stock 1948 dodge frame. im going to be replacing the drive train with an 80's 318 and 4spd and wanted to change out the rear end too. hopefully a 3/4 ton or 1 ton rear end will fit.

 

Thanks 

[Dodge_48]

I put a posi out of a '71 Dodge Full-size passenger car under my '48 1/2ton.  Had to cut the spring perches off the old one and mount them up on the '71, and have a drive line shop modify the drive line.  Damn glad I got rid of the original.  Seals leaked oil onto the shoes, then the brakes would lock up, etc, etc.  It was a pain in the butt.  I had certified mechanics work on that hunk of junk.  The '71 axel has been in my '48 since '79, and other than putting the axel, a spin-on oil filter, and a K&N air filter on it, it is all original. I drove it back and forth to work every day for 18 years after that. That truck has been the BEST rig I ever owned.  I would never sell it.

[Desotodav]

I'm not sure where you're from LameNytro, but I found that the wheels from my earlier model trucks (here in Oz) will not fit on my 57/58 Dodge suburban truck - the brake drums on the later model appear to be larger in diameter.

There have been quite a few member's here that have fitted other diffs under their trucks - maybe use the search function to the top right of your screen?

[Dan Babb]

I put a 1996 Jeep Cherokee rear end under my 52 Dodge truck.  Pretty simple process really.

 

Cut off old perches and shock mounts

Weld in new perches (bought at Tractor Supply) - after measuring and setting the angle.

Install using the original plates that the shocks mount too.

 

I got a unit with a 3.55 rear gear and it works great.   I think the overall width might be around 3/4" shorter than the stock unit...but you can't tell when looking at it.  The original wheels bolt right up to the truck too.

[The Oil Soup]

Looking to do the same to my 53 dodge truck. What type of mounts did you use from Tractor Supply?

[olddodgeguy]

They are weld on spring perches and come in several sizes.  Rear housing diameter and spring width.  They are also available through Jeg's and Summit. Hmmm.  Maybe I should give an example.  Like a 3 inch diameter housing and a 2 1/2 inch sring width.  Mike

Edited July 4, 2013 by olddodgeguy

[Jeff Balazs]

I put a 2002 Grand Cherokee Dana 35 in my 52 3/4 ton. There are several ratios available....I got a 3.55.

Big benefit with this axle is it came equipped with 12 " discs. Had to add 3/8" spacers to get the stock wheels to clear the calipers so the track ended up the same width as original axle.

 

Jeff

[seabee1950]

After trying to tell my Ex Father in Law that just because he got a free rear end didn't mean it would work, with that being said and my butt not on the line I went to work.

 

Years ago I changed a 67 Chevy C10 six cylinder W/a four speed truck trans, just wanting to see if it would work, the rear end came out of a Automatic 78 Ford Wagon not thinking about the gear ratio---well he could not use the 4th gear because it was to high geared and he started out in granny which was like low on a regular trans, but what I am getting at is do your homework make sure you know your trans is matched to the rest of the equipment, grinding or cutting you spring pads & shock mounts off your old rear end would be the best way to go as you know they will fit..  

[55 Fargo]

I have a Mopar 8 1/4 Diff, with 3.23 gears. This works great, I do not have to start out in bull low, 2nd gear is just fine. At 60 mph and with 27 inch tires, I am only spinning just over 2400 rpm.

The downside is in high winds, or hills you maye have to get the rpm up a little higher in 3rd gear before shifting to 4th direct drive. Other than that it is great.

Seabee, what the heck gear ratio did you install, being an automatic in a car, was probably quite high geared. 3.55 seem to be ideal for this swap, but again, am happy with 3.23 gears I have. I do not see the real need at this point to have to convert to a T5 for example..

[seabee1950]

I really don't know guess I could look it up if I were to guess maybe a 3.73 I knew it was to high for the truck but like I said someone gave it to him and he insisted so there he got it.

 

I was just getting to the point that you really need to check the parts and will they fit, it looks like a Jeep rear end out of Cherokee would fit you just need to do your home work. 

[Merle Coggins]

Sounds like you got an axle in the 2.50 range if you couldn't use 4th gear. That would be way too low for a flattie powered vehicle with a manual trans.

[Boss Hog]

Getting ready to have an 87 Cherokee, 3:73 installed in my 53. Will let you know by next week how it went.

[seabee1950]

Yes Merle

There were things like the 235 six which was way to small for the gearing  and the rear end from an automatic car.

I don't think these cars and trucks would last long with this out of order ratio, it would be to hard on clutches,that's why one needs to figure the ratio and what RPM's for take off and not smoke the clutch. the fact that the Jeep rear end being close to what is in the truck rear end is from new will be fine, but I am not sure its going to be the top end you will like so why not use what you have just don't drive faster then the truck will take. 

But hey its not my thing I was just say in, so go forth and experiment that's the only way we find new ways to improve on our rides.

I would never say don't just no what you are getting into before.

  

[Ram Man 02]

i found spring perches at Northern tool as well. $5.99 each

[3dodgedoobie]

under my 52 is a 87--90 dodge Dakota v8 rearend. not ure on gear ratio. it was still factory five lug.  also the rest of the drivetrain is 318 with auto tranny out of 88 fifth avenue. got rid of the lean burn and converted over to 4 barrel. so she will run good and smooth.

[george c]

My '48 has a GM Corporate 14 bolt in the rear and a Dana 44 front end. 318 with a 727 and a 208 transfercase. It all fits and works perfectly.

 

George

[Scruffy49]

Ranger through end of model year 1998. In 99 or 2000 the lug bolt pattern changed.