Dually rear end swap?

[SRadke]

We just lost the rear end in a 92 W250 with 3. 54 ratios. This is the second time because it is regularly overloaded. I'm thinking the best option now is to replace the diff with a dually diff and put a flatbed on. What does it take to make the swap? I'm not interested in a full conversion, just the rear end. The front hubs, brakes etc. will remain W250 stock.



Any tips on locating a rear end? What conversion is required to put in a rear out of a later model (96)? Any thoughts or suggestions appreciated.



-Scott

 

[Paychk]

There are 1 ton single rear wheel axles, their not as common as the DRW, but can be found.

 

[SRadke]

I don't care if it is a SRW one ton axle. All I really want is a Dana 80 in there. Were there 80's in the 2500's those years as a camper option or something?



I pulled the back off it this afternoon and it looks like I've got a bearing on the carrier spun and there were two teeth off the pinion in the bottom of the case. Salvage will be expensive.



-Scott

 

["Mad Max"]

it'll fit, but...

I'm pretty sure the later model housings will bolt up to the springs, but I don't think the e-brakes swap directly over. If you need a killer D80 you might want to see how much a SRW D80 would cost from Dynatrac, in LA. They make them custom and everything is brand new, including the cast iron center differential section housing. Pretty much bulletproof.

- Sam

 

[SRadke]

I really need the Dana 80 and from what I've been able to determine I'll have to get one from a 94+ model truck or buy new. I've also discovered (mostly from searching old postings) that the spring perches are about the only thing that will bolt up. The e-brake cables, shock mounts, and torsion bar will all need to be modified. Also the larger axle tubes in the 80 will require diffrent u-bolt brackets on the bottom. The only way I can see this happening is if I find a parts truck that has all the applicable components. Any other thoughts?



-Scott

 

[1stgen4evr]

Dead rear end

Couple of thoughts on the replacement possibilities. You describe failure in the carrier bearings and overloads. There are heavy duty dana 70 setups that have larger carrier bearings. It would be hard to identify that from a salvage yard. The dually 70 is going to be the same in the center section as the srw. We experienced the same problems that you are having in a 84 chevy ctd conversion that we did back in 87. The Cummins just imposes way too much load on the drive line.



There are some reasonable priced 2500 trucks on the market that you might consider. We bought a rough looking farm truck that was pretty cheap. It has the dana 80 and is fwd. Inside looked like a feed lot but it cleaned up ok. Then you could save the 1st gen for fun driving.



Going to the dually, you might find a complete rear that is from a camper. The dually rears were know as camper special in the chevy line before the "Dually" caught on as the thucks are known now. I have a salvage camper with ford running gear that has a dually width axle. I will probably stay with the 70 on my trucks because of the ebrake issue. My current soultion is to stay out of the heavy throttle when ramping up with big loads. This has gotten me to 390 K with the original rear. My experience with trying to rework a trashed center section has been negative. Must have been a reason the thing failed in the first place. You mention heavy load but that may not be the only thing.



I will be watching this post to see how it comes out as I still have the 80 in the back of my mind.



1stgen4evr

James

 

[Philip]

regularly overloaded

If you go to rebuild the old rear axle. Before you spend one dollar on it. Check the axle housing to see if it is bent. The Cummins can bend a model 70 housing. Here is a link that shows a pic of how bad my housing was bent.



https://www.turbodieselregister.com/forums/showthread.php?threadid=56738&highlight=bent+rear+axle

 

[SRadke]

From what I've been able to determine the bending is the issue. Wheter or not is currently bent I don't know but I do believe that it bends when placed under the toung load of a heavy goosneck stock trailer. I believe the bend to create an improper preload on the carrier bearings (as well as other things I'm sure) thus causing premature failure.



Switching rigs is not at all in the budget right now so this one will get fixed again. If we have to a direct replacement 70 is an option but I was looking for something that might proove to be a little stronger. I do believe it is more a factor of weight than power because this is a stock 160 hp 92 model pickup and it's a real pooch compared tot he stock 96 that I used to have. The problem is that it pulls every day.



Any tips on locating or identifying one of thses heavy duty 70's?



-Scott

 

[Philip]

They are mostly the same axles. The only difference is the width of the axle for the use it had. The brake size is different between the dual tire axle and the single tire. But that is a minor problem. The bigger shoes will fit the 3/4 ton single tire axle.



There are three length axe housings as used by Dodge. You have the shortest one being a single tire 3/4 ton. The Cab and Chassis rear is the next in length. It is 6" wider than the one you have now. The dually axle is the widest. It is around 12" wider than your axle.



Being you have 3:54's you might find an axle pretty easy. My truck has 3:08's it took me 6 months to find a axle to replace the bent one. My engine is almost stock. It only has a couple of turns on the star wheel).



The 70 is about the strongest you can find other than the 80. If you are towing heavy all the time. The 80 could come up with the same issues also. The 80 runs a necked down axle tube out by the outer bearing. (The 80 uses 70 outer ends and bearing). This neck down is past the U-Bolt clamping area. It could bend in this area. IMHO

 

[SRadke]

Thanks guys. I'm going to take it into Six States today and see if they can save it. The junkyards around here are way too proud of their stuff. I'll post how it comes out.



-Scott

 

[dan brooks]

Not sure how much it would cost to have it crated and shipped, but there is a CTD D70 on eBay right now (San Diego area). I've been kicking around the idea of buying it and keeping it around for a spare, but don't know if I feel like driving to SD to pick it up.



Here is a link:



D70 on eBay



As far as the bearings spinning on the carrier, that seems to be a common issue with Dana 70s, especially those that see severe use. Mine spun the driver's side carrier bearing and spit a couple shims, and the passenger side race had spun a little in the housing. Fortunately we caught it fairly early and no damage was done to the ring and pinion, and we were able to salvage the carrier and housing. A new set of bearings and resetting the backlash was all that was necessary in my case.



The bad part is that the price for D70 parts is outrageous - I'd like to install a Powr Loc and maybe regear to 4. 10s, but can't justify the cost right now. By the time you buy a new R&P, carrier, and install kit - not to mention the labor if you don't do the work yourself - it may be worth the extra work to install a D80. Considering the increased GCVW ratings on the later model trucks, I'd be more comfortable with one of them under a truck that was heavily loaded on a regular basis.