Rear Axle Swap?

[JJump]

First Genners,



I have a '93 D350 Dually with a 4. 10 LSD (Dana 70) rear axle-I'm looking to change to a 3. 54 ratio. I’ve talked to a few folks about swapping out my ring & pinion but it’s a bit pricey, so I’ve been looking into a total axle swap which is within my maintenance capability. I found a guy who has a ’97 D350 dually that he’s parting out-low mileage but had a cab fire. It has a Dana 80. I asked him if it would retrofit into my ’93 & he sent the following response…



“Yes it is transferable to your vehicle. The spring plates are alittle over 43 1/4 ' center to center. The only thing that I am aware of that you would have to change is possibly the shock mounting brackets on your frame. ”



I would appreciate any input to the prospect of swapping out my Dana 70 with an 80 from a ’97 second gen. Not really concerned about the rear ABS because I’m presently running without it, but I’m in the dark about u-joints, driveshaft length, emergency brakes, ect. Thanks for your time!



Joe Jump

St Louis

 

[southpaw]

JJump, I have 3 DCD,s all are 3/4 ton autos an 89 w 4:11 an 02 w 4:11 and a 93 w 3:52 the trucks with 4:11 get over 20 mpg but the 93 is around 13 I,ve set timeing, valves and other mechanics that would directly affect fuel consumption with 0 results now I realize i,m spoiled with the 4:11 high milage. and I,m thinking of a rear end swap. however i would also like to go with a 4x4 change also lots of work and no place in commie land to do it will have to wait for Mo. This 93 was bought about a year ago in Poway Ca. with 78k. well maintained and driven by a woman as her personal vehicle it had never pulled any thing she just hauled bird seed in it . The bed had a rubber mat so no scratches just a few lost bird seed. I really like the 1 gen because of the simplicity and the feel of heavier metal I can,t push and bend like the later bodies. You probably want to haul heavier loads than I will so I understand the desire to change ratios. A Question I have is do you expierence similar fuel consumption with your 3:52 ratio? By the way my def is a dana 70.

 

[Not_Agn]

rear axle swap

I have looked into this option also for my 1st gen dcd. You are also going to have to change wheels. The studs and lugnut are a different size. Another problem I haven't researched further is the proportioning valve for the rear brakes. Weather it would work with the newer brakes. Too much or not enough braking going on? I stopped persuing it after I found out about the wheel studs and nuts.

 

[dpuckett]

Joe,

I can find out if someone around here knows where to get a R&P swap done. The Dana 70 4. 10 and 3. 54 take the same carrier, so the only thing to change out would be the ring and pinion. May as well do the bearings while you have it apart, though. I know a guy who put a R&P in Mom's 92 in '01, but that was 2 years ago. I've noticed 3. 54s do better on the highway than 4. 10s, but in town and going under 60, 4. 10s are actually better- keeps the engine in its ideal BSFC range.



You get your low boost problem found? I'll make it up there someday and check things out for you; maybe next week. This weekend is booked up- timing, valve adjust, head bolt torque recheck, maybe injector check. Something somewhere isnt right. There is no reason for me to be getting the MPGs I'm currently getting.

 

[dpuckett]

Joe,



Is the intercooler still good in the Wrecked Old 97? and how much does he want for the rear axle? Dana 80 can get a 3. 31 on the same carrier as the 3. 54, I've been told.

 

[JJump]

Not_Agn



Thanks for the heads-up on the lug bolt pattern-I don't want to get involved with changing wheels! You're right-better off leaving that one alone.



Daniel,



No I haven't found a leak yet in my intake/gauge hookup-haven't had the time to even look. I did see 11 psi the other night on a long steep uphill on the interstate. I was in 5th gear & saw a fair amount of grey smoke in the headlights of cars behind me. I was unloaded & soon reached my top speed (around 80 mph) so the boost fell off pretty quick.



I'll contact the guy & ask him about the intercooler. He said the truck engine/cab was in a fire so it might have melted.

 

[914x4ctd]

not_agn

I may be wrong but I am pretty sure that all of the 8 lugs are the same. I have owned 4 different 3/4ton trucks, 2 Dodge, 1 Chevy, 1 Ford, and all of the wheels will interchange. However the studs are different from Dodge, Ford, Chevy. The only one that I know that is different is the Ford Super-duty '99 up. It has a slightly larger pattern.