i have a rear end from a 83 diesel automatic c 6 with a 3.08 ratio would this rear end be a dana 61?? or just a regular dana 60 or am i way off??? its full floating hubs

 

Sounds like a D60 with 3.08 gears. never heard of a D61 before.........

 

it could be a d60 with aftermarket gears because ford only offered 2 different gearing for our trucks 3.55 or 4.10

 

i thaught that Ford went to the Sterling rear when they brought out the 80 model. Is this rear from an F series? An easy way to tell if this is a Sterling or a Dana is where the fill plug is located. The Dana fill plug is in the rear cover, while the Sterling is located in the front of the center housing, drivers side,just a head of the axle tube about half way up.

 

nope they switched to the sterling rear end in 1985 or 86 they did offer the dana in 3.07 ratio on c6 diesel trucks but it was technically a dana 61 i did some research on the subject and now im posting my findings for all to benefit (: they also made dana 71 with 3.07 ratio. the reason for the 61-71 badges was because they couldn't fit the huge pinion gear inside the case so they had to build a new case with the pinion moved over a half inch or so and the carrier and bearings and axle spline size and count are identicle to dana 60. this also applies to dana 71.

 

When I was trying to find something out about my truck a few weeks ago when I got it I thought I read something about a Dana 61 and Dana 71. It made me go "Whaaaaa?" haha. I was wondering what made them call it a 61 & 71. Thanks for clearing this up for me. =)

-Pat

 

No Dana60 was ever offered with 3.08 or 3.07 gears, including high pinion or low pinion front ends. 3.54 is the tallest available - same for the dana50 front ends. The dana 61 was offered by spicer for automakers that were becoming more concerned with fuel economy in the aftermath of the 1970s fuel crunch specifically to accomodate the taller ratios that the 60 could not.

The Dana61 was mainly offered in E series vans and I think (but not positive) they were mostly if not all, semi floater axles. However it was also offered in lighter F250 trucks. I seem to remember catfish mentioning he had a truck with that rear end at one time (and didn't like it LOL).

Dodge often used the Dana61 for their front ends to take advantage of the 3.07 gearing when combined with their new cummins. Without it, their non overdrive early 12V diesels would have suffered a top speed limit with only 2500 RPM to play with. This I feel is a large reason why cummins trucks from this era to get such good MPGs since 3.07 were so rare behind ford diesels of the era with their 3000+ RPM limit. The higher RPM limit was one reason, but the guttless chevy 5.7 and even 6.2 were another reason very few took advantage of taller gears behind a V8 diesel even if the ford 6.9 was a different animal from those that came before.

I think Ford's sterling rear axle was first available around 1984, but the dana rear axles continued to be found under some trucks after that, I don't know if there is a specific cut off year for the dana61. On paper the sterling can accept 3.08 gears but as I found out, no aftermarket supplier will make them anymore! 3.3-something is the tallest available now...

If that is a dana61 axle it won't be as strong as a sterling but considering how hard it is to get that ratio these days, I would run it anyway if gears are what you are after. Its still fairly tough for what it is.

 

Still have the rear end. Gottas love airplane gears....Only draw back is inboard brake drums but it is a full floater........also the ones that I have seen had left and right hand wheel studs.

 

I had an 84 F250 LD 4x4 with a semi-float D61 rear with 4.10 gears. Seems such an oddball combination now, but I guess they only offered the actual D60 in full float models.

 

Haha, there were some strange things they tried back in the 1980s. Left and right hand lug nuts on the same truck is just wrong on many levels. I heard from others that had trucks like that too. Never heard of inboard brake drums though.

 

what i was trying to figure out... and figured out there was nothing i could do about it. was get 3.07 or 3.08 whatever in a 4x4 truck. the only front offered as a 3.07 was a dana 61 found in a dodge!! and at that it was a right side differential!! this angers me almost as much as david i was looking at the axle tube diameters and even machining parts if i had to. i wouldnt mind putting a sterling rear end under the front if i could get 2 sets of 3.08 gears if i could get custom axles built by moser for my application, but i got to looking at it and the front differential housing has a special cast in piece for part of the spring to sit on and for the ubolts and the front springs set too close to the pumpkin!! arrrg i even have a dana 61 rear and a dana 71 rear with 3.07 gears and a posi, but i dont think i can get the spring close enough for it to work for me! o well, i guess we are just stuck with 3.54 gear ratio. i guess we could always go with a gear vendors, by the time i get custom axle built, even if its at all possible, a gear vendors would be cheaper and less headache

 

i dunno how you guys can stand 3:08's.
i had 'em in two f150's yuk.the second f150 i swapped in 3:55's.it turned it right into a truck with some hauling power.night and day difference out of that little 300/6.
i dont miss them tall gears one bit.no power on the hills and doggy take off.
i didn't even bother running this rig with stock tires.i read enough before she hit the road,to know a little gear reduction wouldn't hurt,and seeing the idi's peak hp was up @ 3k rpm,i wasn't afraid to drop down in tires,man did i choose correctly.she runs nice and strong without struggling.nice happy spot between 4:10's and 3:55's.....right around ford 3:73's is where its at.there's little wounder why many people claim to love these gears for a full time working rig,or even part time DD/occasional 5ver hauler.just a great middle of the road truck gear.
3:08's id be down in 1st gear going 15mph up our steep hills when loaded up.ugg.
im a fuel economy lover as much as anyone,but having changed ratios before,and feeling the power difference,there's no way id go with gear ratio to achieve it.of course we all use our rigs so differently and in such different parts of the county.getting the gearing correct for your application is so important its not even funny.one gear swap after using a rig for a period of time is all it takes to be a believer.

 

thats what i thought!!!

 

According to the Dana books the tallest gear offered for a 60 is 333? A 61 was 307's

They show 60's and 61's each as full and semi floaters.

 

Don't think I would put 3.08s in a small gasser unless it didn't have overdrive and/or was spending 95% of its time above 70 MPH. Maybe a small F100.....

My F150 has 3.55s and I feel it would benefit from 4.10s in terms of power and fuel economy. I don't know much about how the 300 performs across its RPM band, but the 302 in my other truck is sluggish off the line just like you describe. You need to get to about 15 MPH before it starts really pulling. For light driving you don't notice it but if trying to pull hard off the line its almost like waiting for a turbo to spool. Feels like mush.

Jim Allen has what I hear is a really nice book on differentials that I've been meaning to get. Never got around to it though.