Paul S.

I am wondering how involved the job of replacing the rear pinion bearings are? I have done some research on pirate4x4, etc. but have not found a direct how-to for our Dana 70's. Does anyone have a good source for info beyond the FSM? Seems a bit daunting with pre-load, backlash, etc.

I also did some poking around at Timken bearing kits and prices vary wildly. Any good service/price advise would help too.

Thanks!

BigIron70

Use the same mfg type bearing or you will run into problems with pinion debth and preload. Bearings are not all the same spec's Run a pattern on gears before you take the diff apart. Check backlash also. Make sure side bearing haven't spun in the housing. Check end play on the carrier before taking it out. If you find end play then the bearing are spinning in the housing. Dana 70's are known for this. Dial indicator, micrometer, turning torque meter, torque wrench, pinion bearing drivers, seal driver. These tools are needed to do the job. Shims control preload and pinion debth a few thousanths of inch means a big difference. I would not tackle this job unless you have someone experienced to help you and had the proper tools. You could bring pinion to a machince shop and have the bearing removed and new bearing pressed on. I have rebuilt many diff's and these are by far the hardess and take me the longest time to do properly. Shim kit is very expensive also. Good Luck

Paul S.

Yeah, going through the FSM certainly gives a good picture of the details.. I am just having a hard time justifying $500-$750 to have it done. Perhaps it is time to invest in a dial indicator and micrometer..

Buddy Stewert

If your bearings are junk so is the ring gear.

torquefan

The most difficult part is when adjustments are needed to the shims, and you need to remove the new bearings without damaging them. Bearing splitters and a press are very handy. I do not agree at all with the gears needing replaced just because the bearings do, but some adjustment will be needed to get back to an acceptable pattern, backlash, and preload.

BigIron70

You take your chances reusing gears, especially when the truck has very high mileage. Most likely they were noisy to begin with so setting the backlash back to spec may increase gear noise. Setting pinion preload might be more important since too tight or too loose will decrease the life of the bearings. Cleaning metal from housing, metal particle will ruin new bearing. These parts are expensive so setting the diff up properly will increase the life of all the gears and bearing.

Brian.B

if your going to tackle a job like this yourself ,,dont get scared or intimidated,,make sure you have the right tools and a clean place to do it,,maybe even pressure wash the whole rear,,nothing sucks worse than dropping a freshly packed bearing in the sand,,and one other peice of advice i found usefull is to START DRINKING HEAVILY it helps.....

Paul S.

Thanks for all the input. I think I am going to tackle this. After a bunch of research it seems it all comes down to the fine points and if I take my time all should go well. I am in no real hurry so I can afford to take my time...

I will let y'all know how it goes...

Thanks!

BigIron70

Good luck Paul with your rebuild, let us know if you run into any problem maybe we can be of some help.

Paul S.

Roger that! The repair is going to wait until i get back from some work out of town.. Should be towards the end of August. It kills me not to have wheels...