suspect rear axle troubles, swap,fix

[GMichaels]

Ok, I have not taken the cover off the rear axle yet but I can rotate the drive shaft 1/2". Like I need more problems.



I have read through 15 pages of posts ( I am still waiting for the service man) and appears the dana 70 does not hold up well.



So how much better is a dana 80 than 70 and is it worth the swap? I am good a fabrication so swapping might be an option



Lots of mixed facts on swaping a 80 for a 70.



Looks like a shorter drive shaft, spring mounts, e-brake, will my wheels fit on an 80?



Would it be better to fix the 70, although looks like parts are hard to find for this axle from what I have read.



Any words of wisdom, advice? will open her up Sunday to see how bad things look.





1993 5spdget 3:54 dually Miles? 350k excab 2wd

 

[Case500D]

Pull the cover

I think I would pull the cover and put a dial indicator on the ring gear and check the backlash. Also make sure it didn't spit any shims. The backlash should range between 0. 005 - 0. 008". Does the pinion move around at all, or is the seal leaking? My W-350 has a new ring and pinion and bearings and 0. 008" backlash, but you still can rotate the drive shaft about 3/8". This is due to the slop in the spider gears, axles, etc. I put a new Motive ring and pinion plus and install kit in (with help) for about $350.



Jeremy

 

[tugboatphil]

GMan,



I just went through an axle repair, but didn't need anything from the differential replaced. I had the oil leak out and didn't find out until I had crushed all but 5 rollers from the left side bearings. Had to remove the axle housing and get the end repaired at a machine shop. My shop bill was a little less than the quoted price of a salvage axle, less the labor.



Anyway, while I was considering the same options, I saw that RonA had a Dana 80 on his rig. He explained to me how he fabbed his in. If you want it, I could PM or email it to you. Or you could PM him, but I think he might be busy with his intercooler job.

 

[GMichaels]

tugboatphil, Let me pull it apart and see whats wrong. How do you PM someone? Would be good if someone wrote a FAQ on a 70 to 80 swap. lot of info but all spead out in the posts. I don't want to swap, but if I could repair for 300. 00 thats not bad, I see from others that they have spent 800 to 1k. .

 

[1stgen4evr]

How to PM and about the axle

Look at the line under this and every post and you will see the blocked words of Profile, PM, WWW, Search and Buddy. Click on the PM block and that takes you to the window which is somewhat self explanatory as to doing the PM. If you want to PM TugboatPhil, click on the PM block under his post. If you want to PM me, click on the PM block under my post. If that does not help, repost in this forum and I will try again to get you going.



If someone has sent you a PM there will be a red banner in the opening of the forums that will advise that you have a PM. I am going to PM you also so you will see that. Click on the banner. It will take you to the PM message page.



As to the axle, you indicate that you have 350k miles and you wonder if the 70 is good enough. I think they are fine but the 80 is stronger. I too have considered changing to an 80 but considering all the extra 'stuff' I have so far declined to do the work. Mine has 420k miles. I can tell you that there is slack in all of them if you turn the pinion shaft at the drive yoke. Case 500D is right. If you suspect problems, open it up and check the ring and pinion backlash. If you have very sensitive fingers you can feel the pinion when it touches the ring gear and tell without opening it up. The rest of the slack is in the spiders and the axles at the spiders. It all adds up and will seem too much. You may not have a problem at all. Now as TugboatPhil can testify, they do fail and it might be best at this time to open it up and take a look. You will see what is going on and from that can make a better decision.



1stgen4evr

James

 

[MMiller]

Mine had 209,000 trouble free miles of much abuse, trailer pulling, fourwheeling, hole shots, and burnouts. Unless you are planning on truck pulling and twin turbo setup then the 70 should be quite happy.



Like above check backlash. It is very important in any diff, especially behind a cummins. I peeled 3 pinion teeth off when mine failed. I wonder if mine had too much backlash with wear. It might be wise to go and put new carrier bearings, shims, and pinion bearings in.



As above I put a new ring and pinion in, with new carrier bearings and pinion bearings. I did all the work myself and had $350 and change into repairing the rear. Motive gear sounds like the one I got too.



I thought about the diff switch but the only one I could come up with was on ebay for $750, and it was in Texas. Kinda hard to go get it when the truck is broke. I might switch after a 6spd and twin disc clutch, but thats down the road aways. As far as I'm concerned my getrag will be the weak link again.



Michael