D70 3.07 value

[Headshot zod]

I may have the chance to pick up a 3. 07 rear. It has around 300k on it. I know it's a special rear and therefore pricey to rebuild. What could this rear be worth and what might it cost to be rebuilt.

 

[1stgen4evr]

If it needs more than bearings, it isn't worth anything at all. The gear set is not available.



James

 

[Philip]

A SRW axle will not bring the price a DRW will. Those are the hard ones to find.

 

[JLEONARD]

I know I'd like to have one. . the Getrag and 3. 07s would be an awsum combo IMO. I run light and rarely tow anything. Should get mileage into the upper 20s.

 

[pepecat]

I really wonder if Dana will ever release a HD axle that will fit our application that will have the 3. 08 gear option in the future. Dana 80's go to 3. 34 right?

 

[dpuckett]

I doubt with the EPA's fingers in more and more aspects of vehicle performance, we will see many even 3. 73 ratios for much longer. Forget 3. 08s EVER- they are for Dakotas, Nissans, and HD (class 6-8) trucks. I had the chance last spring ('06) to buy a set of 3. 07 front and rear axles for $500. Are they in my shed? Heck no, I passed on them, cause I wanted the dually axle for my pickup, and plain didnt need the front. Geez, I am so stupid sometimes.



The truck I thought I had bought in NJ back in May had 3. 07s and a Getrag. Club cab, guy claimed 22-25 with the pickup bed. Low RPM dont always mean high MPG, though. I think 3. 07s and a Getrag in a D250 reg cab would be ideal for MPG. JLEONARD- I think you have peaked your MPGs at what, 26, 27?



Daniel

 

[JLEONARD]

JLEONARD- I think you have peaked your MPGs at what, 26, 27?

I wish. I'm at 22/24 daily because I drive hard, but I've gotten 25+ if I drive sanely.

I think the 3. 07s would give me almost 2 mpg.

 

[Headshot zod]

Thanks for all the great info.



So what do think I should offer. Is 3-400 about right? The truck has all service records. Is 300k considerd high mileage? I really have no clue.



If this doesn't work out is the Dana 80 w/3. 34 a better option?. I'm looking for top end. Long story... ...

 

[Niki]

I know there are people out there with 3. 07's and manuals, I'd like to hear their take on the mpg, especially switching from 3. 54's to 3. 07s. I know from past experiences that 60-65 mph=23+ mpg for me, 75-80=about 20. I don't know how much of that has to deal with wind drag, and how much is engine RPM...

 

[pepecat]

well I've done 4000 miles in the past 2 months with 3. 07's and getrag OD up and down I-5 @ 75 to 80 with hills unloaded and wasn't afriad to WOT while passing or climbing and I got 24-25 avg.

 

[JLEONARD]

I don't know how much of that has to deal with wind drag

A lot of it is wind drag since they used a brick as the design model for our trucks. :-laf

 

[1stgen4evr]

"if Dana will ever release a HD axle that will fit our application that will have the 3. 08 gear option in the future. Dana 80's go to 3. 34 right. "



Mystery man commented that he was considering having some 3:07s done for the 80. I expect that he would have to presell at least 500 sets before he could get a gear mfg. to consider tooling for that. Think you could get the membership to come up with the 'upfront' money for that project???



It might be worth noteing that the D80 uses the same wheel bearings as the 70. Rear axle failure is more often than not from lack of maintanence, not overload. While the D80 gear set IS larger, it isn't the gears that constitute the achilles heel of the 70. The gear side of the carrier takes most of the load. If you use your truck hard, you need to replace that bearing (and likely all the others at the same time) around 250k miles to be ahead of any possible failure. Most people don't even look at or change the lube till there is a failure. Not good enough.



I don't have a 3:07 set in service but had that in an 89. It got 20 mpg with the 727. I have a front and rear set from a 3/4 ton that is surplus. If I do what I ultimately plan.



I am thinking that with my application (go out loaded, return empty) that I can use the Getrag with 3:07 rear and only use the OD on the return trip. This will take the overload off the Getrag and boost my mileage on the return trip. Should be a win win setup.



James

 

[Niki]

That is what I'm thinking also. Its probably a lot better for the trans if its driven in 4th when towing also.

 

[pepecat]

yeha you can go 55-65 all day long in 4th! It's even better than the 727 too because you have lockup... I can't even shift to 5th until about 60-65 mph... 4th is good up to 85-90 with the 3200 gsk kit but loud.

 

[MMiller]

Its probably a lot better for the trans if its driven in 4th when towing also.

I know that trans temp on mine will run 180-190 loaded up at 28,000# in 4th gear all day lone, and in OD the temps keep climbing until the temp gauge maxes out at 250*, thats usually after about 2 hours of 72 mph in OD. Even with the fast coolers, and 50 wt synthetic transmission oil. I am still thinking of a 12 volt pump and transmission cooler to keep temps in check... ... ... . another story for another topic, but basically I agree with the above statement.



I think that you will be very satisfied with the 307's in your salt flat pickup. I think the 307's would fit into almost any 2wd first gen well, as long as tire size stayed near stock, especially when towing. I can see how getting loads started will be more difficult.



Another section where the 80 is stronger then the 70 is the pinion where the yoke is splined on. On a 70, its actually the same size as a dana 60. Most pullers will break the pinion on a 70, but not on an 80. Not really a huge problem on a "street" truck though. I've never broken one, however I probably should have by now.



Michael

 

[rumblefish]

If this doesn't work out is the Dana 80 w/3. 34 a better option?. I'm looking for top end. Long story... ...

Ever consider a corporate 14 bolt? A Buddy of mine had one with 3. 2x gears. 14 bolts seem to be plentiful, and alot cheaper than an 80.

 

[dpuckett]

What size ring gear is in that 14bolt? What corporate is the 14bolt from? Is it 15% bigger than our 10. 5" ring gear in the 80 (has 12 bolts, IIRC)?



DP

 

[sdstriper]

He's reffering to a GM Corporate 14 bolt, these are Semi-floating. They were used in the Muscle Car era and in alot their pickups but I doubt it would hold up long behind big torque or heavy loads.

 

[Niki]

He's reffering to a GM Corporate 14 bolt, these are Semi-floating. They were used in the Muscle Car era and in alot their pickups but I doubt it would hold up long behind big torque or heavy loads.

GM also made a full floater 14 bolt that went in every heavy 3/4 and one truck that wasn't a dually up to at least 87, 91 in some models. I'm pretty sure they are regarded as just as strong as a 70, since I think they also have a 10 1/2" ring gear. 14 bolts is referring to the number of bolts that hold the cover on.

 

[rumblefish]

^^^ what he said. The truck pullers around here just love them. Cheap and strong. When they break it, if its more than an axle shaft, they just swap in another one. Spring perches are pretty close to our width already. Enough that I've seen some guys just ream the holes out and bolt it up, instead of remounting them.