I have a rear axle from a 94 12v automatic 2wd truck. I am looking at putting it under my truck because it has the factory limited slip and mine is open carrier. Will I find any strength issues switching between this axle and the one that came under my 94 manual?

Also, will I have any drive shaft length issues with this swap?

 

I don't believe it's any weaker if that's your question. I swapped a 2002 Dana 70 with limited slip and disc brakes into my '95 and the driveshaft bolted right up with no problem.

 

The D70 isn't as strong as the D80, but its still pretty beefy. Will it last? Probably, but there are guys that can wreck anything, so its not a guarantee.

Your driveshaft will be about 1.5" too short. You might be able to get away with running the slip yoke out that far, but it would be a better idea to have it made to the correct length.

 

a Dana 70 with a stick shift wont last, the pinion gears break due to the torque. I broke the teeth off of my Dana 70 with a automatic and I also know 2 other people who have done so, and neither of them hot rod at all- plus many vidoes on youtube. The 70 can hold the weight, but the cummins torque will kill the pinion. I wish I could have found a Dana 80 to stuff under my truck but couldnt pass up disk break dana 70 for $200 on craigslist so I put it in and filled it with 75w140 oil and have my fingers crossed.

 

Here is the first time I found the broken pinion, at the time I knew nothing about axles and have never seen one break. all i knew is I had a hole threw the rear cover and something really bad happened- as you can tell from me saying here is "your" this was before I bought the truck from my friend

http://www.youtube.com/watch?v=JhKhzvb9Ax4


installing the Disk brake Dana 70, my i phone wouldnt video well in low light but still a "ok" video

http://www.youtube.com/watch?v=zGDUObZNLEU

 

That being said, 1st gens had D70's behind the stick shift, and they were just as torquey as the 12v 2nd gens. Lots of high HP racers running the 70's as well. But anything can break, and there is likely a reason the factory has put the 80's in just about all the trucks.

 

True the d70 should be awesome, but this experence has me worried as i was beside myself when it broke then I talked to the guy who logged my property who has a 94' automatic and he also lost the pinion- iv never broken a axle in my life and went threw many trucks since highschool and in my younger years abused the heck of of them by holding them to the rev limiter at stop lights and dropping the clutch in 2nd or 3rd with no issues at all, even my old 94 chev z71 half ton with a tiny 10 bolt never broke! heck even back in 01' with my old F-250 powerstroke (viewable at .12 in above video) that has the same axle rateings as the dana 70 I hauled a 12' camper pulling a 20' trailer with 2 jeeps & 2 50G water barrells on it up a 17% paved grade and found myself down in 1st to the floor for a few miles- no axle problems what so ever. (e4od another story)

 

The biggest problem I have seen with the 70 is that the carrier bearings seem to wear a bit prematurely and when they lose their preload, the races turn in the housing and damage the housing. Have seen that several times, and would recommend that if you install a used 70, check before you buy it that the carrier doesn't have any end play in the housing. Also, replacing all the bearings and making sure the preloads are within spec before you install it will help it live a long life.

 

Thanks all. My driving style and horse power probably aren't mean enough to hurt it, but the marginal drive shaft length is a no-no. I have an auto I was going to swap with. If I took the section of the driveshaft from the auto that went from the carrier bearing to the axle and swapped those around too it should all work out right? Both trucks are standard cab long beds. I'll measure those tonight and check. Thanks again.

 

I have measured both drive shafts between the trucks. I do not believe the carrier bearing that supports the drive shaft in the middle is in a different location from truck to truck, so the difference should be in the tube length of the last piece of the drive shaft. They are in fact different by about an inch and change. Is there any reason I cannot split the shaft at the splines by the carrier bearing? I think I am in the clear on this one.

 

The two piece shafts are apparently balanced as an assembly when manufactured, so it may cause a balance problem if you just remove half of the shaft and have it altered.