The Stovebolt Site Forums The Shop Area Engine Shop Planning Dana 70 swap in 46 1 ton

I picked up a Dana 70 today to put under my 47 first 1 ton. It's a heavy duty son of a gun.

I plan on putting in a 3.54 ring and pinion if it doesn't already have one and also swap out my transmission with an SM420 or SM465.

I was reading up on setting the pinion angle. Got a bit lost on the discussions but can't I just measure the current angle and set the Dana to the same?

When I replace the perches do they need to be the same width as the springs?

Anything else I need to be planning out as I do this swap?

Anyone know of a good drive shaft shop in the Bay Area?

Greg

Not that there is anything wrong with swapping to a 465, but functionally you gain next to nothing, same direct drive in high gear but the 465 should be the better choice if you have both to choose from.


Check out this tech tip for pinion angles and such, mostly the links in it: http://www.stovebolt.com/techtips/driveline_setup.html

The perches should be about the same width as the springs, defiantly not wider, as the U-bolts would then not be snug to the sides of the springs, and not much narrower, as you want a good seat/contact area for the springs.

Best to assemble the truck with the perches loose on the axle housing, but layout some center lines so you get them positioned correctly left to right. Then with the truck on a level floor check and correct the angle of the pinion as instructed in the manuals in the link above, then tack weld the perches to the axle, remove and finish welding, or if you can do a good job of welding them all assembled go for it.

If you have a pickup you may have a problem finding wheels to fit inside the fenders when you use the Dana 70. I had wheels made for my 52 1 ton with a Dana 70HD. I also moved the spring perches to correct the center to center distance, but I kept the same angle as the Dana already had. Then later found I had to make 6.5 degree correction shims. So, learn from my mistake and assemble it all before you set the pinion angle.

Grigg

Grigg,

I do have the 9' pickup bed so I'll have to keep an eye on the width. Backing plate width is only an inch wider (53 instead of 52) so I'm hoping it will fit with the original wheels.

The only reason I was going to a 465 was to get the SM gears. The crash box gets annoying after a while. I thought of putting in a T5 but was not sure if it will hold up on a 1 ton.

Also, the Roadranger links on the tech tip no longer work. Do you know where they might have moved to? Or maybe you have a soft copy of the manuals you could e-mail me? [email protected]

Thanks for the tip on the pinion angle otherwise I would have learned the same lesson.

It could be you have the unsynchronized transmission that was available before the SM420? The SM420 is synchronized, at least in the higher gears. I think the SM465 has better parts availability than the SM420, another plus for the newer version.

Try this one for the Application guide:
http://www.roadranger.com/ecm/idcplg?IdcService=GET_FILE&dID=137495

And this one for the instillation guide, probably the one you need most: http://www.roadranger.com/ecm/idcplg?IdcService=GET_FILE&dID=137499

If those don't work I'll email you the file. The Tech tip should be revised shortly to show these new links.
Grigg

Thanks Grigg, the links worked.

Currently the 1 ton still had the original 216 with the original transmission so it's not synchronized. I'm going to be putting in a 235 for some extra power. The current 216 is in bad shape as it sat for around 20 years. It started right up after fluid changes but won't last much longer.

Wish I could put disc brakes on but shortening a front axle like you did is well beyond my skills.

'48 was the first year for the SM420. A '47 has the earlier crash box with the reverse lockout on the shift lever if its still original.

You'll have to change bellhousings to use a later transmission and the clutch linkage may need to be changed too.

I know of no reason to choose the SM420 over the SM465. If you have one I'd run it.

Backing plate width isn't the crucial measure. What is the difference between the widths of the wheel mounting surfaces?

I have a 1-ton with a GM 14-bolt rear with 3.54 gears or something like that. It came to me with a 216 and an SM420. The guy I got it from said the tired old 216 did not have the grunt needed with those gears to haul a load.

Now this was a tired motor, but if that axle comes to you with 4.11 gears or something like that, I'd suggest driving it before deciding to swap the gears, you may decide it needs the gears to do the job.

My one ton with a 235, SM420, 32" tires, and Dana 70HD with 4.56 gears was geared to slow unless really heavily loaded. I would have preferred 4.11, and would have tried 3.73, although that may be to fast? As it was it was comfortable at 50-55 mph, but would go faster if needed.

Grigg