Robert Rausch

Back in May I bought a Dana 70, 2001.5 disc-brake rear-end on ebay. I got it from a salvage-yard owner I had bought Dodge/Cummins parts from before. I paid $650 for the complete rear-end, sight unseen, although after I bought it, he did send me an email picture of it. He's a good guy. I posted a picture of it here on the DTR, and got some feedback, and now I want to update the story.

Here's the rearend after I brought it home:



On the bad side, there was some condensation inside the pumpkin, and a few of the spider gear teeth on the right side spider set had surface rust on them, but the ring and pinion appeared to be perfect.

I also put new axle seals on it, and had a new pinion seal installed by a mechanic since I didn't have any way to torque the pinion nut afterwards. I had one heck of a time getting the correct pinion seal for it. NAPA showed the wrong part numbers--they kept ordering the seals that their parts book called correct, and when the seals came in, they would be wrong. Oreilly's couldn't seem to get the correct one either. Finally I went to the Dealer, and got the exact, perfect pinion seal for about $30. Sometimes it does indeed pay to go to the dealer!

On the good side, the 2001.5 rear end turned out to be a Power Lok! The guy who sold it to me had told me it was a non-Posi rear-end, but when I pulled the rear cover to inspect the innerds, there were those clutch packs staring me in the face. The guy's yard helper, saw them and said, "Hey... it's a Posi!" And I just replied, "Yep". But I had paid for it by then!

More bad news was after I got it up and running one of the calipers was sticking pretty badly, so I replaced both. NAPA had a decent price on rebuilt calipers, so that's the way I went. Threw some new pads on it too.

Here I've dropped the old rear-end down on the ground:



I did all the work myself, and since a Dana 70 weighs a heck of a lot, I used my old Farmall to pull the old one out, and move the new one in. A 4X4X12 came in awful handy too, to lever up each end so I could bolt it in place.



Scary moment. I've got the truck supported on 2 jackstands, backed up by two floor jacks.



Hey, I've got disc brakes!!!!



This disc-brake rear-end is a little wider than the old one, and the tires stick out a little, but I like that. I can now see more clearly where my tires are when I'm backing up just by looking in the side mirror.

I filled it with fresh 85W90, ran it about a month, and then drained it and refilled it with fresh 85W90.

Robert Rausch

And I gotta say, I LOVE having rear discs. Back when I had drums, I'd adjust them, and they'd be ok for about a month or two, then they'd be worthless. I did a LOT of nose-down stopping then, having to press harder on the pedal. I got really tired of braking like that, and I hated having to crawl under the truck, jack up each rear tire, and adjust the drums.

I almost can't believe the difference. I use way less pedal pressure, and the truck doesn't nose-dive when stopping now. I just towed a trailer 1,600 miles, and stopping was a pleasure instead of being a pucker factor.

1workinman

Sir did you have to change the master cylinder to a different year model. thanks

Robert Rausch

I did not change out the MC. I didn't change the proportioning valve either. I just hooked up the rear-end and drove away. It seems to work just fine.

Robert Rausch

The only difficulties I had were after I connected the brake lines I evidently didn't tighten them all sufficiently because I did spring two leaks. But I just got out the flare-nut wrenches and torqued them a little tighter, and they're nice and dry now.

I also used SpeedBleeders on the calipers. Them make it easy for one person to bleed the brakes.

Hodge

How much wider is it?

Robert Rausch

Actually I didn't say it correctly... the rear-end itself is not any wider, but the wheels & tires sit out further, due to the width of the rotors and emergency brakes, so with the disc-brake rear end, the tires end up sitting out about 1.5"--2" further out on each side. I haven't measured the difference exactly, but if you look at the last picture above, and compare it with the way a stock wheel sits on a Dana 70 drum rear-end, you'll see how much further the wheels/tires stick out.

By the way, on this rear-end, the emergency brakes are drum brakes that are incorporated into the inner portion of the rotor casting--that's why the rotor castings are so wide, because there are drum brakes inside. With the aftermarket disc brake setups, like those I used to see from EGR, they used a different emergency brake set-up which used the discs.

Robert Rausch

Compare these two pictures. The second one is my disc-brake rear-end and it does have a stock wheel mounted, but you can still see the difference.

samiam4

I thought there were some residue pressure valves in the m/c to keep the drum brake cylinder tight where the disc doesn't need it.
Are your brakes dragging in the rear at all?

Robert Rausch

Not that I can tell. But since you mentioned it, I'll check and see if they seem overly hot next time I can.

Robert Rausch

I asked quite a few people right after I bought the rear-end if I needed to change out any valves or even the master cylinder. As a rule, the people who sold brake parts recommended I buy their valves and their master cylinders, and make the change, while the guys who didn't sell brake parts said I didn't need to change anything and I wouldn't have any trouble with the new rear-end. I've driven the truck on wet roads, but not icy roads, and so far, no problems at all. Braking is soooooooo smooth and easy. Wish I'd done this years ago.

mprmnc

Not trying to bust on you, but I wanted to let you know that the 2001.5 rear should have a Trac-Lok, not a Powerlok. I only point this out in case you ever need to replace those spider gears or want to buy clutches. I believe there are different clutches between the two.

Robert Rausch

Thanks mprmnc. This rear-end is a Dana 70. Now on page 3-43 of my 1995 Ram Truck Service Manual it says this: "Trac-Lok differential is available on 9 1/4 axles, and Model 60 and 80 axles. Power-Lok differential is available on Model 70 axles." Now that was for 1995. By 2001.5 they might have changed the specs for a Dana 70 from a Power-Lok to a Trac-Lok. I'm not sure, but I was calling it a Power-Lok based on what my 1995 Service Manual said.

I have no experience tearing down either the Power-Lok or the Trac-Loc, but my Service Manual goes on to say the 1995 Model 80 Trac-Lok uses 6 disc and 5 plates, while the Model 70 uses 2 disc and 3 plates for each clutch pack. I didn't check out the clutch packs when I installed this rear-end, I just bolted it in place. I wonder if there would be an external I.D. on this rear-end to tell me whether it was a Power-Lok or a Trac-Lok? Mostly I'm curious... as long as it works well I'm not real worried about which one I have.

The limited-slip definitely works though. Before, with my stock rear-end I could get stuck on wet, muddy grass. But the last rainstorm I was out in my barnyard powering around like nobody's bidness.

mprmnc

Yeah, they switched from primarily Power Lok's to Trac-Loks around 1999-ish. The '95 would have had a Power Lok, the '01 should have a Trac-Lok. I tried to find pictures of each this morning and found several pictures of Power Lok's, but none of a Trac-Lok. On Dana 60's they are EASY to tell apart, on the 80, not so much. And I'm just not sure on the 70. The Dana 70 Powerlok case is pretty obvious, here is a picture of what it looks like.

Now, the Trac-Lok case could look very similar or more like an open carrier. If it looks like this picture with a bolt together, two-piece case, you need to check the where you can see the cross shafts. If the holes are round and the shaft just fits into the hole, then it's a Trac-Lok. On the Powerlok case the holes are oval and the shaft fits into a V-shaped notch (look closely at the picture.) If the case looks like an open carrier with clutch packs on each side, then it's definitely easily identifiable as a Trac-Lok. I'm sure you probably didn't pay that much attention to the case when you had the cover off, and if it's working well I don't think I would bother to go in and look. Just wanted to make you aware that there were two different differentials in case you ever did need to order parts.

I actually just installed a disc brake rear from an '01.5 in my '98, but mine is an open diff. A friend did give me a Powerlok from a '98 dually axle he had and I'm getting ready to install it with 3.73's. I also did the matching front axle though. Here is the link to my thread in case you wanted to check it out.
https://www.dieseltruckresource.com/...s-t274122.html

Danderson

Dodge should have put rear discs on back in '94. For maybe $200 more they could have bragged about the superior braking performance instead of being hounded with complaints by owners. The customers would have gladly paid. "Overbuild it and they will buy."