Hello all, first time posting. I have a 2004 F250 4x4 V10 115,000 miles, 3.73 gears. Bought it on 05 Dec 2009 from Bill Hood Ford in Hammond LA. Has a loud whine coming from the rear and my new truck mechanic says it's easier to swap the rear end than rebuild it. He told me it's a $300 part and about $800 of labor and taxes. The used rear end is from a similar 2004 F250 (obviously) and has ~83,000 miles. It seems like a lot of miles to me but mechanic says they rarely go out and the previous owner must have towed the crap out of stuff and probably skipped a lot of scheduled maintenance. Ideas of the swap and it's consequences and costs? Thanks to all! Ray

 

Does not sound right to me. Has he identified the source of the noise? Gears, bearings, wheel bearings? If not, he's just shooting blindly and he knows if he replaces the whole thing he won't ever have to figure it out.

General automotive shops may not be the best place to take differential work. A shop that specializes in that work might be better. Like a place that does a lot of gear swaps.

The would be a real good time to regear that V-10 if that's something that interests you. And if you tow much it should.

 

A whining noise could be the ring and pinion...
but it could be a number of other things as well like Bill said. Bearings, seals, etc..


Just dropping a used axle in isn't the end of the story. Does it have a matching ring and pinion ratio the same as the front axle of your 4x4? If not, you need to pay to have the front regeared or transfer case problems will happen down the road. Also, what are the condition of the brakes on the new used axle? Seems like you'd at minimum want to replace the brakes since it'd be convenitent with the axle out. And the parking brake? It needs to function in order to get a state inspection (if applicable in your state).

A new axle is feasable, however, if your old one has problems with more than just the ring and pinion. It might be time for a 2nd opinion to make sure.

 

Thank you for the response, I had the same question; what is making the noise?

We took a test drive around the block and it is noticeable at low speeds and the noise is still present while in motion and the transmission in neutral. He says in order to diagnose the actual problem things would have to be disassembled and it's just best to replace the rear end. This diagnosis is exactly what the sales guy at Bill Hood told me when I bought it. Yes I bought a broken truck for a song so I knew I had to sink some money into it. The sales guy says in about 10,000 miles it would need to be replaced. I have driven it less than 1,000 miles so far and the noise is still the same.

I have replaced the old highway tires with new AT tires (not to stop the noise) so that eliminates tires. I work in IT so my ability to hear an automotive noise and have a clue what it is lies between never and very unlikely. The automotive guy I went to came highly recommended by family and a high school friend who works a local advanced auto, he does quality work at reasonable labor rates. Of course I would rather replace a $100 part and perhaps 2 hours of labor but I can only relay what the mechanic told me.

I will be towing a 17' & 22' boat and perhaps some small/medium utility trailers but overall just to pull the boats. I pull them locally and it's very flat and dry. I have no aspirations to change the gears. The mechanic did mention he does not rebuild rear ends and rarely swaps them as they do not normally go bad so he did mention a specialty shop a few miles away that does that kind of work all the time.

Thanks again, Ray

 

At most I can say it sounds like tire hum. The noise from the rear end increases in pitch as speed increases and is present at all speeds above around 10-1 5MPH. I can discern no other sounds that are seemingly out of place.

 

This is the key. He is only offering to do what he knows how to do. Have to give him credit for being honest, that he is in over his head. That other shop he recommended should be your next stop.

 

The gear ratios in both the front of the existing and the rear of the new replacement match as the mechanic told me they have to.

Good call about the brakes on the new rear end, makes good sense to me and I will make sure to address that as part of the fee. I told him I did not know the history of the truck when purchased so I wanted him to put it up on a rack and give it a very thorough once over to make sure nothing is missed for scheduled/routine maintenance. This will be done at the same time of the rear end swap so I hope there are no other issues to deal with.

 

The other shop is where the used rear end is coming from. Since it's just a swap and not a rebuild the local mechanic can handle this. He explained that a rebuild is a good way to ensure known good parts are introduced into the truck but it costs on average $500 more than a swap and his crew is not accustomed to rebuilds, similar to a foreign language if you don't use it you loose it.

I've already made arrangements for 02 Feb 2010 to have the work done by the local mechanic so I have some time to have it looked at by other mechanics.

 

I can see where a swap would be less expensive than replacing a gear set. But you have to wonder about condition of the boneyard axle. Would really suck to get it swapped and then find out this one whined too, or had a bad axle bearing, pinion seal, or whatever. Personally I would have them repair my original.

 

I hear ya. I would really like to know what is causing the noise before a blanket rear end swap but the money involved to have a mechanic break it down is cost prohibitive I think. When the mechanic told me it had 83,000 miles I was very skeptical and told him so but he assured me that it would last another 83,000 miles and will come with a 90 day warranty. He says if anything goes wrong it will happen in 90 days. It also saves me about $400 which is a great thing.

I might give the other specialist a try but I have to take off from work and sit all day. I might call them, that's free at least!

Thanks for all your help so far

Ray

 

Did you check the fluid in the rear end? Is it full? Does it smell burnt?

 

My rear end has close to 100K more miles, and it has towed alot. All I have done is check the oil in it and keep it toped off, plus a lube change at 100K.

Now the hub bearings I eat every 60K.

If it has not been run low, I would look at them first.


Your best bet is to just take it to the shop, that is just where I would start.

 

I'm not sure if any maintenance has been done. Looks like changing the fluid change I might be able to handle but I wouldn't know if the gears look wrong by visual inspection.

If the problem lies with gears, bearings or other inside components not easily accessible then at about $85/hour with at least an hour probably 2 then it seems like a gamble with my money to diagnose what's wrong and then I'll have to pay again to have the faulty piece(s) replaced. Seems like a bad video game....

Wish I had more time/tools to perform my own repairs.

 

The hub bearings are easy to get to, they are not in the rear end but behind the brakes on either side.

I repack mine every brake job and relace them every other.

Does the axle have the proper amount of fluid in it?

 

Any of these pics look out of place? This rear U Joint (that's a U joint right?) always looks damp compared to the front one. I saw no leaks or huge dents on the rear diff, have not checked the fluid, looks tricky actually.