Not sure what to do here as I sit in the home depot parking lot...suppose it be more helpful if I was stuck at an auto parts store but we can't all have that good of luck. Ha

Anyway, driving this morning I noticed whats probably best described as a grinding noise. It was ok then suddenly as I let off the gas pedal I heard a "clang clang clang clang" as if the muffler pipe fell off. Ok no big deal I was waiting to find a spot to pull over and as I accelerated the clanging went away and the grinding got louder. Again I decelerated and the clanging came back. Clearly this is something in the drive train. Any thoughts? I'm about to call the transmission shop to fix her (Im out of town living at my sisters so I have no tools or time). I would just like some thoughts so I know how much I'm going to get beat for

 

Kind of sounds like a rear... Could be U-Joints but I doubt it. If it is U-Joints you can climb under and it'll be obvious...

 

Don't think it would be that easy for me...at least with my luck LOL thanks I'll shake down the driveshaft and see.I mean it's a start!

 

Certainly sounds like it could be the rear axle assembly. Which type axle is it? F150 could have an 8.8" or 9", and the F250/350 had several different options over the years.
If the axle needs replaced, this would be the perfect time to upgrade to the better type and/or ratio (unless it's 4WD).

 

I'm going to go with a failed rear end.

A bad rear end will do all kinds of god-awful things depending on the problem.

When you left off of the gas, what it's doing is letting all that slack come back in the rear end. When you get on it, it takes the slack out and starts the grinding. Your ring gear and pinion are probably about toothless. Its probably been howling for a while now too, as they usually do when they start to go.

 

It's definitely been howling but not very loud. I've asked mechanics and they just said drive it. I took my dads old school advice and just turned up the radio. Haha.

Basically it grinds when rolling. Gets louder when accellerating and I have come up with a better description here...it sounds like a jake brake when I let off the gas. Just as you said the slack releases and clanks/grinds. I reaccelerate and that must put tension amongst the ring and pinion.

Truck is an f-150 4x4 with lower gearing (3.55's)? Not really sure but it's 4 wheel. If I were to make the gears taller can I just disconnect the front drive shaft on the 4 wheel? I don't think I have ever used it intentionally.

Anyone know what something like this runs for a repair? My brother in laws friend is doing the work (he owns a transmission shop) so I wont get raped but the work regardless and parts still cost.

I did make it to my job site this morning. Whew! Time to empty the tools out, tow it to the shop and use my car. Nothing like driving around in a dodge caliber SRT/4 sport car to carry tools and lumber. Hahaha

 

Yep, your rear end is bad.

When they start howling is when you need to watch out. I'd be questioning those mechanics. They may have wanted you to keep driving it so that it could get parked in their lot.

 

Since it's 4wd, you'd be better off just rebuilding/replacing the rear axle and staying with the 8.8" and current ratio. You never know when that extra drive axle could come in handy........
I'd have a look inside the current axle assembly and see what will be needed to repair it. If the cost of parts is more than a couple hundred dollars, might be best to hunt for a salvage yard unit with the correct ratio.

 

It sounds from your description like a failed pinion bearing. Now you have a basically trashed ring and pinion. The grinding is probably what's left of the bearing, the clanging comes when the load direction changes.

 

with the likely damage in there, your best bet is probably to just buy a used axle and drop it in. might change the fluid in the replacement and inspect it as you're doing so, but thats about all i would do to it.
it cost me about $1000 to have a used R+P installed in my dana 60 by a local transmission shop, so axle work is expensive.

 

Even if you ruined it by driving it more, don't worry about it. It's cheaper to buy a used rear axle than it is to rebuild one.

1/2 ton parts are cheap.

 

Ouch $1k for a used rear? Sheesh I only paid $800 for the truck LOL oh well I'll see what he says then decide from there. I do use the truck for work so I kinda need it. Damn...

Thanks for your input I'll start looking for a used rear just in case. Guess I'll have to get my powerstroke back in service for work use. Hate doing so. It's in clean condition!

 

Hey granny rocket where are you located? (Fellow South Jersey poster here). There's a guy in Maple Shade parting out his 85 2wd F-150 on craigslist. Maybe he has his rear still.

 

Maybe you'll be lucky and it will be correct ratio and a 9".

 

Get out! Right now the truck is down by long beach island where I'm working but I live in the Glassboro area. Maple shade is close by relatively speaking. I'll check it out!

On a side note, what would be a good ratio to look for if suppose I was to swap. I don't really use the 4x4 and my '96 powerstroke is 4x4. So is it really worth keeping? This truck should be fine in the snow as the bed/cap is always loaded with tools. Just curious if a 3.23 or higher ratio would be good for fuel economy. My 84 olds cutlass came with a 2.56 and that was a dog off the line. I'm afraid to go that (numerically) low!