New Diff install

[BHerring]

Hey all,

I am going to install a new Power Lock diff and would like to know some pointers before I start this job. I never done a diff before, so I need to know if I need any special tools, what is the alignment procedure, etc. I am a gear head and will be able to figure this out, just looking for some experience pointers.



Any information will be greatly appreciated. .



Brad

 

[TBartlett1]

Go to Randy's Ring and Pinion and buy their differential repair book it will tell you everything you need to know.



My recommended tool list.

1) Dial indicator to measure backlash.

2) Micrometer

3) A large heavy soft mallet to install the carrier.

4) Setup bearings for the carrier to allow you to easily change the shims for proper carrier preload. These bearing cones are machined oversize and slip on and off, or you can make your own by using an air grinder (die grinder) to enlarge the bearing ID so that they slip on by hand.

5) (2) ½ X 10 or 12 inch carriage bolts to install in place of the lower cap bolts to ease removal and installation of the carrier.

These bolts support the carrier and allow you to easily roll the carrier into place and support it as you work it into place. You can also leave the main caps on the carriage bolts and when the carrier is in place you just flip the caps up and push then in place, install the top bolts remove the carriage bolts then install the bottom bolts and tighten.

6) Case spreader to do the job right, being this is your first time.

Many have posted that they did not use a case spreader but I would recommend it so that the carrier can be properly preloaded. The D70 requires 0. 012 to 0. 015 preload, not positive on these figures. Attempting to install a carrier with this much preload may be near impossible if this is your first time.

 

[dpuckett]

Dont forget the inch-pound torque wrench to do the pinion preload.



I used a 24" pipe wrench to hold the pinion nut in place to tighten it to 350ft-lbs or whatever the book calls for.



Prussian Blue or some similar marking compound to do your contact pattern.



Look up a thread by 1stGen4evr, something to the effect of "Dana 70 rebuild. " I went from the info in that thread, and in the Factory Service Manual, and have logged 7000mi so far, so good.



I didnt even check my backlash- I just got my contact pattern and preloads, and let her fly.



Daniel

 

[AVerHage]

Honestly I would suggest a different diff. Some people may have different opinions but every one of these I've seen cannot hold up to high torque. I've never seen one in a diesel but I have seen one shatter in a '96 tahoe with stock drivetrain after only 7 days and another in a K5 Blazer with a 400 and 4. 56 gears after only a few hours. I run Detroit Lockers front and rear, and I'll swear by them, they also cost over $500ea. If you look on Randy's Ring and Pinion, ringpinion.com, they suggest not using powe4r locks in big tire aps or high power, I'd say a cummins stock is the latter.





Otherwise the other replies are good, if it's your first diff it may take a few hours but they aren't that complicated, once you've done a few you can get a Dana 70 done in about 45 minutes.

 

[dpuckett]

Correct me if I'm wrong, but isnt BHerring talking about a regular clutch- type limited slip? i. e. original equipment? If so, I've had them hold obscene amounts of torque, with a GCVW of ~25K. Not saying there arent better options... ... .

 

[AVerHage]

I may also be wrong but it sounds like he's talking about the Powertrax True Lock, that's what I am refering to as a weak piece of junk.

 

[BHerring]

I am glad for all the replies and information. To clear the air. I am going to install the Power lock limited slip, (dont know if i have the correcet way so spell power lock)



dpuckett. . is this the type off diff you have used?



AVerHage... I dont know what true lock is?



Let me know what you guys thing, becasue I would rather buy a good diff and not a POS.



Thanks

Brad

 

[AVerHage]

We still may be talking about different pieces,True Lock is a piece mad by "Powertrax" that's the brand name. It should not be used in any application. I'm not sure what the intended use is for it seeing how even they say not to push it. Its a posi that utilizes your stock carrier all you do is pull your spider gears out, and I think this is why it fails. If you get something thats engineered as one unit, (new carrier) and you use all new shims bearings, and seals, even new ring and pinion is the best bet. I know it can cost some money but in the long run it's cheaper just to knock out the entire axle. I've found that if you replace one part that was weak now something else is the weakest and will break. I like Detroit lockers the best for our trucks but ARB and others make quality packages

 

[BHerring]

Ok, this is a complete unit, so its NOT the "powertrax". I am going to have it installed on Tuesday. Just to give you an Idea the cost is about 490 for the diff and 220 to install. I talked to the guy and he understood what the Powertax true lock and he said the same thing, he didnt like them, however with my unit I get a new carrier and bearings and if the diff does break down then I can use stock parts to fix it, please dont quote me on this, but this is what the gear and diff guy said.

 

[dpuckett]

That doesnt sound like a bad price- hope he knows what he's doing and takes his time. Sounds like the stock unit. I hate how everything sounds so similar- Power Lock, trac Loc, powertrax, etc, etc. Why cant they just say, OEM limited slip, or ACME unit to convert your open to LS?



I cant use a locker, because the twice or so a year I tow, I toe the line on my 24K plates, making a locker undesirable.

 

[BHerring]

dpuckett,

I am taking to a shop called Pro Gears and is located in San Diego. I called and asked about my dodge and he told me that someone backed out of this diff about 7 months ago and he wants to get if off his shelf and is giving it to me at cost! He has done work for me, on my race car, he installed Aurburn Limited Slip and has been very good to me!!! He did tell me its powerloc limited slip diff. I get confused about this powerlock or powerloc, ture loc, etc...



Here is the link to pro gears: Welcome to PRO GEAR



I will let you guys know more on Tuesday evening, (Tuesday is when the new diff is going in and no more spinning wheel when there is a water on the road, espically at a stop sign or stop light!!)



Thanks for all the information!!!



Cheers

Brad