[PowerStrokeMeF450]

Since no easy lockers are available for the Dana 80 w/ 37 splines I'm getting ready to take the plunge on a real LSD. I'm thinking in theory here, and seeing if anyone agrees or if I'm crazy for even thinking it.. but if I replace the open diff with a LSD unit and the ring/pinion are the same and all caps/shims re-installed exactly as they came out, there shouldn't be any reason why I run into a major setback on setting backlash/pinion depth etc. right? I know Murphy's law, but if the LSD is the same dimensionally as the open carrier, nothing should change right?
Of course I'd set up the dial indicator when I'm done and torqued and check it, but if it's out then I'll have a lot more down time trying to locate shims etc. Shouldn't be out though right? All that would be new is the LSD carrier and new bearings pressed on with the same ring gear bolted onto it.

I'm looking at a Yukon YDGD80-4-37 most likely. Open to suggestions if anyone feels there is a better unit.

 

[cainbr]

This was correct when I installed an Eaton Truetrac LSD in my sterling 10.25. I was able to use the original shims. When I set up the dial indicator to check it tested within spec.

 

[PowerStrokeMeF450]

Thanks for sharing that cainbr. If I get to feeling like it's simple enough I'll pull the trigger on an LSD. I'm also looking at the Truetrac as an option. About $100 cheaper and once it's filled with just GL5, no service needed. But I really like clutch type LSD's in my cars and from racing etc. Not like it would be the same in the truck though. But I did read the Truetrac is rated for more torque which has me looking at more seriously it too.

 

[PowerStrokeMeF450]

I went with an Eaton Trutrac as well. Better for truck applications. Also Eaton wants just good-ol conventional 80w90 gear oil. Nothing added and no synthetics. Makes for cheap easy maintenance.

I have the diff and gear oil and a new cover gasket. But in my research it seems repair manuals and instructions say to replace the 12 ring gear bolts and they seem pretty adamant about replacing the ABS toner ring. I have never replaced ring gear bolts before as they are very strong. (9/16x18 grade 9) in this case. And the toner ring? Why?

I am holding off on tearing into it until I have everything I need. I feel that I can get the toner ring off without damaging it with a little heat. And with proper cleaning/lock-tight I don't see why reusing the superstrong ring gear bolts would be a problem. This is another $200 in parts for no reason if I can re-use my old stuff. Does anyone see any reason why I should just bit the bullet and buy them? I suppose it must be easy to break the toner ring. Why else would it be suggested for replacement? If it is a known PITA then I will buy it. Pretty sure I will reuse the bolts though. Thoughts?

 

[PowerStrokeMeF450]

I will be doing the swap on my next day off. I went ahead and ordered the toner ring to have on hand in case something happens. Plan to return it if I can reuse the original. I will be reusing the bolts too. I see no reason to change them. Maybe if I was doing a rebuild on a damaged diff. But in this case, a good clean up of the threads and holes and lock-tight with proper torque should be fine. Hope it goes well and clearances stay in spec!

 

[animalv]

how did the carrier swap go? did you have to change the tone ring?

 

[PowerStrokeMeF450]

I will be doing the swap this Sunday (hopefully). I held off because I wanted to have a shim kit on hand and a better bearing puller (one that doesn't destroy bearings). I ordered them and still waiting. I found out that the shims go behind the side bearings on the carrier. This means I may have to pull bearings a time or two and re-shim if the backlash is out. I wasn't planning to have to pull the old bearings just to get to the shims and potentially damage them in the process. So I need a new shim kit just in case. Just makes for a potentially longer/harder job to get it done right and all to spec.
In fact the right way to do it is pull and press my old shims and bearings onto the new carrier and install/check backlash, make any shim adjustments if needed, meaning pull and press them again, then once satisfied, you pull them again and use the new bearings as the final press/install.
At first I figured (and may still be right) that the swap should go pretty easy just using the old shims in their same place and the old toner ring and ring gear bolts. But someone mentioned to me that the diff is old with a lot of wear and tear. This got me to thinking that just because I'm not experiencing any issues with the diff, doesn't mean the clearances haven't come out of spec. This will be the time to get it back to that .005"-.008" backlash spec. So I just have to have all this stuff on hand just in case. I still plan to use the old toner ring, ring gear bolts, and shims if they don't break and are sitting good. Hopefully I can return anything I don't use.

 

[PowerStrokeMeF450]

Well I got screwed with a stupid $17 shim kit getting lost in shipping. One of those "says delivered" but not here situations. Rather than fight it for now, I just ordered another set and will deal with the several days of messaging for a refund on the original set later. This way I should have them here sooner and be able to shoot for next Sunday for sure. Looking forward to finally doing this job and snapping some pics for y'all. I'm also upgrading to a sexy cover with a drain plug for easier service rather than the cover-pull for service method.

 

[PowerStrokeMeF450]

Two days till install. To confirm some of my research, or does anyone have better info or suggestions?

I have found torque specs of:
80 ftlbs for the axle bolts
80 ftlbs for the main caps
220 ftlbs for the ring gear bolts
40 ft lbs for the cover
(These are from a Spicer instructional PDF)

I have a backlash range of .004" - .009" (for a used ring/pinion) new is a little tighter .005" - .008"
I have a pre-load of 9 - 11 inch/lbs (for a used diff) 25 - 50 inch/lbs for a newly assemble diff.

I am not removing the pinion, just the ring/carrier assembly and going back together with hopefully the same shims. If not I will reshim to get within backlash spec. Anything else I should know?

I was thinking I'd start by pulling the drive shaft, cover, and axles out and measuring both the inch/lbs it takes to turn the assembly from the pinion nut and the backlash that it currently sits at and aim for those same measurements when I am reassembled. This should cover me for both pre-load and backlash specs if all goes well. My thoughts on it are that being that the diff is well used with 247,000 miles on it, and because I am having no problems with it, whatever the specs currently sit at should be fine, as though I never had a thought on it and just continued using it. Even if the specs are slightly out, it's not like I was having a problem right? But of course I'll aim to get the specs within tolerance. I just think maybe I'm too fearful and overthinking it. Any insight is appreciated.

 

[PowerStrokeMeF450]

Install went smoothly, diff works great. Already drove through my muddy field and noticed a huge difference. Other than bumps it was like driving down a road. No more wheel spin! Unfortunately I found my pinion to be loose as well as my driveshaft center support bearing. So I will be removing the whole carrier again to replace the pinion bearings. At least the carrier is set up and will go in and out quickly next time. I will separate the drive shaft to pull/press a new center support at that time as well. I will continue with the break in once the pinion is solid again. Don't want to drive it a lot until then. Parts are on the way already.

 

[PowerStrokeMeF450]

Weeks after my install (which turned into a full diff rebuild) I just wanted to share my thoughts on the available driveshaft/diff components. If you do any work on your rear end, go with Spicer parts. I used mostly Timken, Yukon, and Spicer. The only part to let me down was a Timken pinion seal which I replaced with a Spicer one and the difference in quality was night and day. The parts from Yukon were rusty on their surface finish and cheaply packaged. Everything from Spicer was packaged with care, clean, bolts had pre-locktight on them. Just superior in every way. I trust Timken for bearings as most do, so I won't be unhappy with them on my carrier and pinion, but I would just go with Spicer all the way if I did it again. The full job took 9 hours and a bit of that was screwing around with sub-par replacement parts. I also noticed that Yukon is in love with themselves and charges almost double for any part they sell, not just upgrade parts, but OEM replacement stuff too. Same with that USA-standard gear and axle brand. The Spicer parts are usually the same price or even cheaper and you are guaranteed quality and proper fitment as the OEM manufacturer. And as a technician being around a lot of parts, I am just really impressed with the Spicer parts. It's like they care how it looks. All their parts even down to bolts are finely machined and it's meant to show. The metals used are heavier and just have that quality dense feel.

Just sharing my experience and lessons learned for those that do this after me.

The Eaton Truetrac is awesome BTW. The truck will never be a 4x4, but it's right between a 2wd and 4x4 now and is incredibly capable. I couldn't even get it stuck when I tried testing it out. It works like a ladder when you look at its grab/release marks on the ground. One side at a time grabs and moves forward. Pretty awesome paired with the 4 A/T tires I put on the DRWs. Can highly recommend the unit to those that find themselves in need of some off road work but only have a 2wd truck.