Noise from rear end!!!

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Mar 17, 2002 | 01:44 PM

Wilber15

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From: Duluth, MN

Noise from rear end!!!

I have an 86' f-150 4x4, and when i let off the gas and step on it again i hear a *clunk* in the rear end. It's not the U-joints, because i've checked them and their solid. I also took the back pumpkin cover off the differential and i'm not missing any teeth. Is this just the case of worn out ring and pinion gears? I've heard that older trucks get this problem after years of wear. I'm not goin to replace the set because the trucks for sale, but i just want to know if this will hurt the truck or if it's just an annoying addition..hahaha. It isn't a big noise, but i can feel it inside the cab when i try and make it *clunk*. If i ride the gas easy, i don't even feel it. thanx for any advice u guys give..laterz!

Mar 17, 2002 | 02:48 PM

kspilkinton

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From: South Kitsap County, WA

Noise from rear end!!!

Are you 100% positive the noise is coming from the rear? A worn out xfer case will *clunk* too. I have a broken bearing retainer in my rear and it doesn't make any *clunk*. You can feel it, but no noise. The noises that I can hear (clunks, slapping...etc.) are from the xfer case. This is because of the NP208 aluminum case with steel parts. A poor design and it will wear a lot quicker than the rear. The clunk goes away when I shift to 4wheel. You may want to double check the entire drive train.

-Kerry

Mar 17, 2002 | 05:50 PM

scionti 94

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Noise from rear end!!!

Could be the slip-joint (inside the rubber boot)on the shaft between the the transfer case and diff. I understand they dry out and need and grease from time to time. Mine is making the same clunking sound upon accelerating from a stop. I am told you remove one of the clamps, slide the boot out of the way, and shoot some grease in there. Slide boot back into position and put a new clamp or a quik tie on it.

Tampa Bay
'94 EB,5.8,towing package, Rancho RSX7000 shocks,Westin nerf bar, Energy Suspension poly, keeping it basically stock

Mar 17, 2002 | 10:28 PM

Wilber15

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From: Duluth, MN

Noise from rear end!!!

[updated:LAST EDITED ON 17-Mar-02 AT 11:29 PM (EST)]I had the truck up on the lift in my high school auto class(auto 1 last year, and auto 2 this year) last spring, and when i turned the driveshaft, the rear wheels had play in them. they wouldn't start to turn until the driveshaft made about a 1/8 of a turn. maybe not even that much. but the driveshaft would turn with the wheels off the ground before it engaged. thats why i think it's the rear gear setup. not the transfer case. the xcase seemed solid.

I could also turn the rear wheel while in the air, and it would spin for a sec. before it caught with the driveshaft.

Mar 18, 2002 | 08:09 AM

winfordr

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From: Rural Florida Panhandle

Noise from rear end!!!

I think you're right in you analysis. Mine does the same thing. But because it doesn't make any whinning or gear noise, doesn't leak or vibrate, it is ok, and will probably run another 100K miles without incident.

Winford

Mar 18, 2002 | 09:25 AM

kspilkinton

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From: South Kitsap County, WA

Noise from rear end!!!

Sounds like you did the investigating already

...some people don't and just show up with the question.

As long as you don't drive like you want the clunk to stay the rear should hold for a while. Like I said above, mine has its own problems, but has lasted 50k miles with them. It's all in how you treat the vehicle.;-)

-Kerry

Mar 18, 2002 | 04:25 PM

Wilber15

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From: Duluth, MN

Noise from rear end!!!

Thanx for the reponses. I also hate it when people just come ask a question to without even looking at the problem area. I heard from a few people that the rear end would be ok, but because they weren't mechanics, i just wanted to be sure. I don't drive it like a typical teenager either! I am 18, but take better care of my baby than most adults!! It's my first truck, and i love it! But it's for sale..lol.