Stock Leaf Springs Mounted Over Axle? Rear end mystery...

[JAS]

Got a rear end from a yard, they had it in storage.... supposedly, its a 1980 datsun PU, but the axle is under the leaf springs as a stock mount.... Am installing in a 79 620 KC, but puts the rear end ride height way to high... What is this rear end? A 4/4 rear end? it does have extra leaf springs... 4 instead of 3 on my KC....

I have added another spring to de-arch the springs to make them acceptable height for me, as this is my mountain truck. I am mostly on the B210 forum, but i have had this truck forever and the old rear end is bad.

 

Just wondering what this rear end is from? Searched already....

[ariascarlos1990]

Its probably an '80 4x4 720 rearend.

[JAS]

I'll make it work then, must be a real low ratio too. Need the truck for this years gold season. Got a lot of equipment to haul with it. At least I got a 5 speed to compensate. I have to get into some real rough country this year.

[ggzilla]

1980 4x4 probably had 4.625 or 4.375 or 4.111 ratio

[datsunaholic]

The top perches are a 4X4 thing.  If it's truly a 1980 4X4 rear end, it has 4.375 rear gears in it.  A bit lower than the 4.11s a '79 MANUAL transmission would have, same as an Automatic though.

 

Is your old axle housing bad?  You could simply change the 3rd member (the differential) into the old housing, which would solve the spring perch issue. 

[datzenmike]

2wd. '79 620 were 4.11, '80 720 2wds were 3.889 if 4 or 5 speed. All automatics were 4.375.

 

Only '80- King Cab 720 4x4 were 4.625 all others were 4.375, there were no automatic 4x4s.

'81 through '82.5 were all 4.375. All 4x4s after that were 4.11 and mostly C200 diffs.

[JAS]

My 79KC was an automatic, did the 5 speed conversion and engine rebuild 7 years ago.Don't know the flavor of the 80 rear end except its 4X4 now with top perches. Will leave stiff and raised slightly like I have it installed now for weight and stump jump'n. Got some good gold property that is way out a jeep trail, will take a skinny truck to get all the equipment out there.

[datzenmike]

Well crank the front torsion bars up and try to get it closer to level. Raising will cause toe out and the camber will tilt the tire tops in slightly. Will give good ground clearance off road though.

[JAS]

Think I got it all the way up now. Got some 245-60-15 tires on it now. They barely fit the front. Would like to get another couple of inches lift in front... But don't see how.

[datzenmike]

Fitting the axle below the springs adds about 5-6" and you're not going to get that much from turning the torsion bars up.

[JAS]

Yea, I added the large flat leaf spring from my other spring set to the top of the 4X4 pack and tightened it down, it gave back about 3.5 inches of arch. But will be pretty stiff.

[wayno]

My 1980 datsun 720 4WD had 4.625 gears in it, your engine will be screaming on the hiway trying to keep up with traffic unless you have some huge wheels/tires on your truck.

Just cut the perches off the top, and weld some on the bottom to fix the height issue, you might even be able to just weld them on the bottom and leave them on the top, I can't remember about that being an issue, leaving the 4X4 perches on that is.

[JAS]

Think I got it with the addional leaf, got a decent 5-speed and BIG tires (see previous response). I do need the heighth for clearence and for weight, just don't want to look too out of whack... I gotta carry some serious equipment into the boondocks on goat trails this spring to set up camp and the sluice/pump systems.