Exploded Differential

[MontanaFORD]

I have a 1978 ford, well most of it's a '78 250. But I recently ( around September ) blew out my gears. I wondering if I should go to the Dana 66 or get another ford 9" rear end? I plan on upping the gear ratio so I can at least cruise the highway in my highboy Anyway, I want to replace the entire rear end because the gears originally were not matched with the front. I know you're not supposed to have the exact same gear rations in the front and rear. They're supposed to be one off or something like that? It'd help if some one would confirm that. So my questions are should I go with the ford 9" rear or the Dana 66 and how are the Rations in the front and rear supposed to be matched.

[michael69]

They are suppose to be the same. If not one is spinning faster than the other and will cause things to break. May be why your is broke?

[MontanaFORD]

Thats how it broke I believe. I was aware of the problem ahead of time. I'm not sure what the ratios are but they're around 4-10 (front) and 3-18 (Rear) I'm not sure how the ratios go I'm trying to go from memory, back to September. Oh I'm also very new to automotive mechanics.

[michael69]

You need to find out what the front ratio is and use same ratio in the rear. Or decide what gear you want to run in the rear and then match front to the rear.

[MontanaFORD]

Awesome! Thanks, I've been scouring the 'prints of front and rear axles but I can't find the one I'm looking for. Maybe it's because I hardly know what I'm looking for. Do you think I should replace the rear then the front? It'll be more work but I'd have more control over what my gears were right? I think thats my best choice. like I stated previously I'd like to be able to at least hit 80 and 90 top with out my RPMS wracking up to 4 grand ( I max out at 4k, I don't want to go high for fear of throwing a rod or something. I'm running a '73 429 Bigblock from a scrapped Thunderbird ) You're input is much appreciated!!

[My427stang]

How does an F250 have a 9 inch? Wouldn't it be a Dana 60 already?

[MontanaFORD]

I think it was replaced by the previous owner, I'm going off of what I've been told. Maybe it is a Dana 60. Though the impression I received was it'd been replaced with the 9' Like I've said I'm pretty new to this, and I've yet to actually get to tinker with most of the trucks inner workings.

[michael69]

Yes you can do the rear first. Just don't use 4 wheel drive untill you match the front up.

[michael69]

I think it was replaced by the previous owner, I'm going off of what I've been told. Maybe it is a Dana 60. Though the impression I received was it'd been replaced with the 9' Like I've said I'm pretty new to this, and I've yet to actually get to tinker with most of the trucks inner workings.

Does it have an inspection cover(removeable cover)on back side of rear housing or do you have to pull center section out the front of rear end housing? 9'' You have to pull center section out front of housing.

[MontanaFORD]

I'm pretty sure it has a removable cover, but to be sure when I get home Friday I'll take pictures and throw them up here. To the best of my knowledge it does have a removable cover.

[michael69]

If so it's not a 9"

[MontanaFORD]

Do you know which one is better? 9' or Dana 60? or is there another one out there that is better than those two?

[forrestbump]

Do you know which one is better? 9' or Dana 60?

Kinda depends on what you want out of your truck.

9" Ford = Great for hot rods, lighter than a Dana 60, easier to change gear ratios, strong, multiple gear ratios...pretty long list of pluses.

Dana 60 = Better for a truck that is used for hauling weight, has full floating axles and because yours is a '78, it'll have 30 spline axles.

If it were my truck, I'd keep the Dana 60 as F250's are usually used for hauling weight, not a$$...

[MontanaFORD]

Alright, I'm not sure quite yet which way I'm taking this truck in. and

One more question is, what would have caused the rear end to do that? One day I was driving and the back tires locked, which killed the truck. when I turned it again, after checking to see if the tires were still in one piece they'd seized. I know I wasn't running it 4wheel, I'd never touched the 4wheel drive shifter thing. Since I haven't seen my truck in a couple days I think it has 2H, 4L and 4H or 2H, 2L, and 4L ( and neutral ) Oh and it punched a hole in the Differential. It made a terrible grinding noise the last 3 miles of my trip.

[forrestbump]

Any pictures of your rear axle housing center section after she let go? That'll help!

...after 30 plus years of abuse, lack of maintenance, shoddy repairs, inferior parts, bent (possibly) rear axle housing...the list goes on as to 'why' it let go. Because your gear ratios don't match, a PO has done something and Lord knows what that may have been.

Never drive a 4WD on dry, good traction, surfaces while the transfer case is in 4 High or 4 Low with the front hubs locked. The binding can/will damage drive train parts...usually the weakest link is what will let go...

If your rear axle housing center section is extremely damaged, look for a complete Dana 60 as a replacement. 1973 and up Ford Dana 60's will have 30 spline axles (better than 16 spline axles)

Most pick 'n pulls charge about $150.00 to $250.00 for a whole unit.