rear differential blown, what now?

[DThibault]

OK, not a week after putting in new injectors and turbo housing, I hear a crunch and the rear wheels lock up in the driveway on the ice. I haven't been beating it, HONEST! Too much snow and ice. The truck had a hard life before I bought it 5000 miles ago as a beat spray truck, taking 400 to 500 gallons of water (spray) across plowed fields. I checked it out underneath and a little oil is weeping from a tiny convex hole in the differential cover. I haven't taken the cover off yet but I know what's in there. My question is, will a properly rebuilt Dana 70 stand up to a truck that is turned up a few HPs? I've never rebuilt one myself so its gonna cost me a grand. I'd love to learn but its always been a mystery. Junkyard one is $800 but will probably have to be gone through. I also found a Spicer 80 from an 01 with disc brakes in a junkyard but its $1500. What's the general concensus here? Thanks

 

[DThibault]

I forgot to mention that I was getting a vibration when under power that I could not place. Clutch in, clutch out, right turn and left. Do you think I found it above?

 

[Philip]

You found the vibration most likely.



Myself I would just rebuild it. But I do know how to setup a R&P. If you have a serice manual it can walk you threw replacing the parts and setup.



The biggest item is a dial indicator and magnetic mounting base.



To reset the carrier I would buy an extra set of bearings and hone them oversize. This way you can remove the bearings easyer for shiming the carrier.

 

[Tippin Spotted Cow]

That rear axle should be able to take that HP, no problem. My truck has 249k miles on it, I bought it from a farmer that used it to tow a massive 5th wheel trailer offroad around his farm, and on the freeway (in overdrive yet) and I've got it pretty cranked up now and my rear end just leaks a little. You may have had a bad U-joint. That would cause a vibration at certain rpm under certain loads, its kinda hit or miss. A bad U-joint can literally vibrate enough to damage other parts though. Thats actually how I blew my first transmission. U-joint rattled it until the case snapped in half.



But for what its worth, it could just be the age that killed it. I'd figure out what it was before you put a new one on though. Only thing I can tell you for sure, its it wasnt the HP. Youre new one will handle that just fine.

 

[DThibault]

I may try it, I mean to rebuild it myself. I forgot to mention that it a limited slip unit, Is that any tougher to do. Where would I start looking for parts?

 

[Philip]

I normaly buy my drive train parts from a place called DTS in Detroit,MI. They normaly have the parts in stock. The prices are just as good as any other places I have found.



DTS - Drive Train Specialists

 

[KOG]

Limited slip rebuilds exactly the same, just uses the LS carrier. Parts price is slightly higher as a result.

 

[JLEONARD]

If it were me I would first start looking for parts locally... . you probably have a shop around that specializes in axles and driveshafts. I know there are several around me. You might be able to pick up parts yourself and get some pointers from them as well if you are a little leary of doing the work yourself.

Are you anywhere near Mass Diesel? Scott may be able to help you out some as well, he's a pretty good guy.



Good luck.

Jay

 

[TBartlett1]

Checkout Randy's Ring and Pinion, good prices and they have a tech line so you can also talk to someone if needed.

They also have a book (which I purchased) that is very good and covers virtually all axles currently in service. Read the book $29 and then decide if you want to do it your self. The book gives much more info and is easier to understand than the shop manual. Axles will no longer be a mystery! I also have info that I can send you (e-mail) that I have on the subject.

You will need to invest in some special tools such as a case spreader and a dial indicator with a magnetic base. It is not easy the components are heavy and requires attention to detail but once you've done one you may find that you actually enjoyed it.

Hope this helps.

Note: I'm currently rebuilding my D70.



Tim

 

[DThibault]

I put the truck in the shop today and took the cover off. Pretty frosty in there, it was about 5 degrees last night. Anyway there were chunks in the bottom so I pried out the carrier and the pinion was in pieces. What causes them to go. I briefly looked at the ring gear with my uneducated eye and the pattern seemed to be in the correct place. Anyway, I ordered the book TBartlett told me about and I will see if I have guts enough to tackle it.

 

[Philip]

Could you give the a tooth count on the ABS sensor ring. That is the ring with the teeth on it that goes between the ring gear and the carrier assy.

 

[DThibault]

I'll check it out the next time I get to work on it. What does the tooth count tell you on that ring? Mine is pretty beat up from the pinion shrapnel but I can still make out the teeth.

 

[Philip]

I need the tooth count for a trans swap I a wanting to do.

 

[SRath]

It sounds to me like you bought your truck with a bad pinion bearing. Is your's a single or dual rear? If single, I have always liked the GM Corporate 14-bolt rearends (10 1/2" ring gear) better than Dana 70's. GM used both, with the Dana 70 usually configured for dually use and the 14-bolt for single. The 14-bolt is considered at least the equal or superior to the Dana 70 by most off-road magazine comparisons, too.



The 14-bolt has better pinion support and can be found easily everywhere. It is also easier to work on. I don't know how the wheel-mounting-surface to wms or spring center to spring center distances match up or if you can get around the tone ring provision if you need one, but it might be cheaper and stronger and worth looking into.



Another bonus is the ease and low cost with which a Detroit Locker can be installed in a 14-bolt.



I have a Dana 80 in my 2nd gen '96 and have been considering the same 14-bolt swap. I find the D80 to be very bulky and lacking ground clearance and prone to getting hung up when off-road or even just plowing deep snow. But I mostly miss having the bullet-proof, ultra-reliable traction of a Detroit Locker, which is only made for 4. 10 and higher (numerically) D80's. I have 3. 54's. The factory limited-slip my D80 has is not even comparable to a Detroit Locker. My understanding is that the Dodge Dana 80 uses Dana 70-sized axle shafts anyway. The 14-bolt will handle any load I haul and all the power any Dana 70 will. I don't care if I lose my truck's 2wd anti-lock feature (tone ring), either. Just more junk to go wrong IMO.



I'm into old-iron Chevy's, so maybe the newer model 14-bolts even have tone rings? I just don't know. But I do know you can find a good used one for alot less than the $1000 you said you're looking at to rebuild your D70.



The first gen Dodge and the old Chevy Dana 60 front axles interchange easily, so maybe the rears would, too. A little tape measure work at the junkyard should tell the tale.

 

[DThibault]

Philip, 119 teeth, some of them were quite beat up but I counted them twice and it came out the same both times. I've heard the antilock wasn't worth a darn in these things so I'm not going to fix the ring. Is that not a good idea?

 

[DThibault]

Srath, my housing is OK so I am just going to fix this D70. I just put all new brakes in it and a neighbor is going to give me a hand and show me how to set up the R and P. The pinion bearing looked OK from the brief peek I took through the back. I'll take a better look when I take it out. That would better explain the vibration than broken teeth as it was more consistant. We'll se next week, thanks for your input. I had Chevys and GMCc for years before I bought my first Dodge. Never had any rear end trouble or transmission for that matter. I figured it was just the extra diesel torque. Always looking for more power.

 

[Philip]

Thanks for the tooth count.



Don't worry about fixing the ABS system. It wasn't that good of a system when new and they didn't improve the older they got. :-laf

 

[tugboatphil]

Since it was mentioned here previously, I am going to ask. What exactly is a Detroit Locker? Is it like a Limited Slip only it's fully engaged? I know I could look it up, but I enjoy asking relatively stupid questions and having you guys verbally abuse me.

If you do have the answer, please word it as though you were talking to a semi-functioning idiot.

 

[Tippin Spotted Cow]

From one semi-fuctioning idiot to another...



Detroit lockers are fully locking rear ends that are controlled from inside the cab. I believe the detroit lockers use compressed air to control theirs. I have seen electronic lockers with just a standard 12V switch in the cab to engage or disengage them also. Their mainly used by hardcore mudders or rock crawlers, as you obviously cant use them on dry pavement. It makes the wheels spin kinda like a toy car where theres just a rod for an axel all the way across. If one wheel is doing 30mph forward, the other wheel is doing 30mph forward, no ifs ands or buts. Between lockers and limited slip is like the difference between a center differential on an AWD and a transfer case on a 4x4.

 

[JGrefenstette]

Since it was mentioned here previously, I am going to ask. What exactly is a Detroit Locker? Is it like a Limited Slip only it's fully engaged? I know I could look it up, but I enjoy asking relatively stupid questions and having you guys verbally abuse me.



If you do have the answer, please word it as though you were talking to a semi-functioning idiot.

:-laf:-laf:-laf you crack me up phil... . i feel the exact same way, i just love hearing what Pete has to say about my stupid questions. half the time he wont even answer them, he just tells me to get off my lazy butt and look em up myself. haha yea the verbal abuse makes everything just a little more fun around here:-laf