Limited Slip upgrade recommendations

[AMikonis]

Looking into having the bearings replaced in my differential. Thinking about switching to a limited slip at this time. Am I remembering correctly the Dana Powr-Lok is about the only LS available for the Dana 70? Don't think I want a locker since I'm primarily street driving. Any advice from anyone who has upgraded? Costs?

 

[JLEONARD]

Please take good notes and some pics as you do it.....

I want to follow suit someday.

Jay

 

[83 crew cab]

have you looked into the power-trax drop in lockers not sure if they make one for a 70 but it works great in 60 I have not that noticible on the streat George

 

[Speedo]

Powr-Lok

The Powr-Lok is one of the best limited slip differentials available. It can be set up several different ways to increase or decrease its effectiveness. There are some old discussions you could probably find by doing a search.



Gus

 

[dpuckett]

I know a guy in Perryville Mo (1hr S of StL) that has great prices on Dana differential stuff- like <$50 for a genuine Spicer LS clutch set for Mom's 92 (clutches only, gears were still good). If you're interested, I can dig the # up for you. Obviously, you'll have to get a new carrier, but it is the same for a 4. 10 or 3. 54 ratio, thankfully. Are you going to do this yourself?



Daniel

 

[AMikonis]

As much as I'd like to learn how to set up differentials, I'm not going to do it now. After a thorough inspection, I'm pretty sure my bearings are toast and the carrier bearings have no preload left. It's not making noise, but I want to get it rebuilt before it gets any worse.



So my thinking is since I need this work anyway, the cost difference to upgrade to a LSD, is the price of the LSD, no? That's what I'm trying to figure out. Hopefully, the ring and pinion is okay, if not I may be over budget.

 

[1stgen4evr]

differential setup

AMikonis



I did my first ring and pinion setup about 40 years ago and have done a few since. The most difficult part of the job is getting the shims right. The design of the dana doesn't lend to easy setup as the bearings have to be put on and then trial fitted in the carrier or pinion houseing. If you did a lot of them you should get a set of bearings and have them honed to a slide fit. Bearings are close enough tolerance that you can interchange after the trial setup and expect to have the same fit. The factory has jigs and measurement devices so that they don't have to do the trial fit.



A new ring and pinion set requires set up.



New bearings on the other hand should only require a spreader for the housing so that you can get the carrier back in without difficulty. You are not really setting up the gear mesh. Pinion depth and ring to pinion fit should be the same for new bearings if there are no other issues such as bent housing, excessively worn caps and bearing shoulder seats. From other posts re the getrag, if you can do that work, you can do the dana.



The dana system does require something in the way of a presss to remove the old brgs and install the new ones. Remember to only press on the hubs of the brgs and not on the other parts. Removing the pinion races is easy as running a bead on the bearing face. That will shrink the race and it will tap out. I use a low hydrogen 1/8 rod to run the bead. There will be some mess from the weld but that can be cleaned which you will certainly be doing anyway. If you are not good with a welder, get someone who is as you don't want weld strikes around the bearing / seal lands.



When/ if you do the job, get something and clean out the tubes as there can be crud in them. As you take things down, mark each item as to left and right and not just lay them out some where "like they go" as they will surely get knocked in the floor. Set the ring gear carrier back in with new bearings shimed just like it was originally. Satisfy yourself that the preload is correct and remove it to do the pinion bearings. If it is not, you will have to add a shim under one of the carrier bearings. Here you can damage the new brg removing it to add a shim. Careful.



Then the pinion. If you overtighten the crush sleeve on the pinion when setting the preload, start over with a new sleeve.



The one issue that is subjective is that you might want to change by one or two thousands the carrier bearing shims so that you engage the ring deeper to the pinion to accomodate a bit of wear in the ring and pinion. This involves the swapping of shims from one side of the carrier to the other. The industry term for what you are doing here is "developing" the setup. Here again you can damage a new brg pressing it off and on. This may sound involved and I guess that it is a bit so. But get all that done and you can expect good result.



I have never had good result when there was a serious failure in the rear end but you indicate that the gears are not noisy and are other wise ok.



1stgen4evr (and probably getrag forever)

James

 

[AMikonis]

James, thanks for the informative post. I'm going to print it out and stick it in my shop manual. I did farm the work out after all. I got a very strong recommendation on a shop, and I have no heat in my garage. I took it all the way to Detroit and had it done while I was there on business. First time I've put a vehicle in a shop for other than exhaust or tires in many years.



After a lot of research, brain picking, and searches on this site. I decided not to go with the limited slip. I think with my weather pattern here, and my driving habits and needs, I may be better off without it. Plus, the Powr-Lok is pretty pricey for the 70, in the $450+ range. That would be an expensive experiment. Also, I just got 4 Bridgestone Blizzak winter tires and I'm quite impressed with them...

 

[Midnite]

It sounds like you've already made up your mind, but I have to say the powr-lok was darn near the best mod I made to my '92. The local 4x4 shop that did the work set it up pretty stiff at my request, and the traction difference was just incredible.



I *really* *really* wish I had this on my 2000.



Mike

 

[AMikonis]

Well, for about $1000, I'm sure you can get one in your 2000, too!



My reasoning was I rarely get off the pavement, and I was looking for an edge in the occasional snow. I was concerned the truck might be a little squirrely in snow with LSD - it's a 2wd. I think this may not be as much of an issue with a 4wd(?) Seem to remember the front of my old 4x4 turbo diesel did most of the pulling when it was snowing anyway.



It really doesn't snow all that much here anymore, and when it does they salt everything to death. I got my snow tires, I should be fine.

 

[Midnite]

Originally posted by AMikonis

Well, for about $1000, I'm sure you can get one in your 2000, too!

Heheh... yeah, and it would be a good time to get a Mag-Hytec diff cover too. But I'm wondering if I have a dribbling injector--sometimes I see some black oily splatter on my driveway by the tailpipe, so I may be looking at getting bigger injectors sooner than I thought. The big thing though is our daughter, who was just born a couple weeks ago--the birth was a little, er, "interesting", so I think we're going to be looking at some seriously hefty hospital bills (the main thing is she's perfectly fine though).

My reasoning was I rarely get off the pavement, and I was looking for an edge in the occasional snow. I was concerned the truck might be a little squirrely in snow with LSD - it's a 2wd. I think this may not be as much of an issue with a 4wd(?) Seem to remember the front of my old 4x4 turbo diesel did most of the pulling when it was snowing anyway.

Well, in 4wd it'll certainly act differently, but once I got the powr-lok in my '92 I almost never had to use 4wd on snow and ice. When I put it in 4wd I could handle almost anything. In fact, I put it in a ditch with more than 3 feet of snow last winter, and I was able to drive it out without any trouble.



In 2wd you just drive it a little differently. I actually prefer how it drives with the tight limited slip myself.



Mike