# bad clunk



## the new boss 92 (Nov 29, 2008)

well the last storm of 12 inches+ i now have a clunk un the passenger side floor board. i cant figure out what it is and i want to make sure its nothing important. does any one know what this could possibly be its driving me up a wall and i cant find it!


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## the new boss 92 (Nov 29, 2008)

oh yea i forgot, its a 1992 chevy single cab short bed with a 5 speed trans with a boss 7'6 super duty plow!


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## RichG53 (Sep 16, 2008)

What kind of a clunk. ???? When doing what???? A little more info ......


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## the new boss 92 (Nov 29, 2008)

only in reverse. its more of like a rattling clunk i dont really know whats under the truck but i do know that its not right and would like to get it fixed! and i dont know if its a common problem or not with the obs chevy or if something just came loose.


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## Dondo (Dec 8, 2009)

I might be having the same issue.

After the first storm with this truck my 89 K5 is making a bang noise under my passenger seat when I go in reverse. It only happens in 4 wheel not 2. It almost feels like the transfer case is slow at shifting into R. This is what is happening. I push a pile forward, shift into reverse with my foot on the brake, you can feel the trans shift into R, then after about 3-5 feet of backing up you get this bang under the passenger seat. Before this happened I installed new rear u-joints. The front U-joints looked good as did the trans mount. This is my 3rd K5 I'm plowing with and have never had this problem. The only thing different about this truck is that it has the auto-locking hubs and only 65,000 miles. 

Does any of this sound like the same problem you are having?


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## JustinD (Jan 14, 2008)

Exhaust? The exhaust on both of those trucks run under the passengers side floor board, thats where the cat is located, maybe you broke an exhaust hanger? Just a thought?


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## Dondo (Dec 8, 2009)

JustinD;931545 said:


> Exhaust? The exhaust on both of those trucks run under the passengers side floor board, thats where the cat is located, maybe you broke an exhaust hanger? Just a thought?


Good thought... I will check the truck when I go home for lunch and will let you know.


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## the new boss 92 (Nov 29, 2008)

JustinD;931545 said:


> Exhaust? The exhaust on both of those trucks run under the passengers side floor board, thats where the cat is located, maybe you broke an exhaust hanger? Just a thought?


im thinking the same thing, but i removed the cat on my truck due to it doesnt need emmissions any more. im also thinking that to because one of my exhaust manifold studs broke. but when i get under there to wiggle it, it is tight. but does it really have enough flex to possible hit the floor board that hard in reverse?


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## the new boss 92 (Nov 29, 2008)

were is b&b he might know!?!?


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## Dondo (Dec 8, 2009)

Dondo;931562 said:


> Good thought... I will check the truck when I go home for lunch and will let you know.


nope, the exhaust hangers look good and everything seems tight.

New Boss - Does yours bang in 2 wheel, 4 wheel, or both?


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## pmorrissette (Sep 15, 2008)

Check your engine mounts, tranny mounts and the frame where it tapers in & up towards the engine bay. I had a '92 K1500 and the frame had cracked there. Welded it back together and added some gussets.


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## Dondo (Dec 8, 2009)

pmorrissette;931704 said:


> Check your engine mounts, tranny mounts and the frame where it tapers in & up towards the engine bay. I had a '92 K1500 and the frame had cracked there. Welded it back together and added some gussets.


I'll check tonight when I get home but wouldn't bang in both 2 wheel and 4 wheel then? I hope my frame isn't cracked!!


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## Dondo (Dec 8, 2009)

Dondo;931716 said:


> I'll check tonight when I get home but wouldn't bang in both 2 wheel and 4 wheel then? I hope my frame isn't cracked!!


I couldn't wait and the truck is only a couple miles from work so I went and checked. All the mounts look good and the frame looks fine at the bend on both sides. When I have an extra set of eyes I will put the truck in gear with my foot on the brake and rev the motor to double check those mounts but they looked good just sitting there and didn't move when I pulled on the pry bar.


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## the new boss 92 (Nov 29, 2008)

ok im going to go cheack for cracks and mounts and get back to you guys in a hour or so!


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## the new boss 92 (Nov 29, 2008)

i just cheakced it out my y pipe is kinda just hanging there and all the bolt from the manifold to the y pipe broke! oops time for headers!


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## the new boss 92 (Nov 29, 2008)

thanks for all the help guys i apprecheate it once again!


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## B&B (Nov 4, 2006)

Dondo;931537 said:


> After the first storm with this truck my 89 K5 is making a bang noise under my passenger seat when I go in reverse. It only happens in 4 wheel not 2. It almost feels like the transfer case is slow at shifting into R. This is what is happening. I push a pile forward, shift into reverse with my foot on the brake, you can feel the trans shift into R, then after about 3-5 feet of backing up you get this bang under the passenger seat. The only thing different about this truck is that it has the auto-locking hubs and only 65,000 miles.


 Classic symptom when running the auto lock hubs on a plow truck due to the constant forward/backward direction change. When you reverse, the auto hubs briefly unlock and then relock, thus placing some slack in the front driveline which will be transmitted through the drivetrain and can appear to stem from the T-case or front drive shaft. Auto hubs are never a good idea on a plow truck and should definitely be changed over to manuals.

Run it long enough and you'll be forced too anyway as the autos will wear out/break anyway.


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## Dondo (Dec 8, 2009)

B&B;933062 said:


> Classic symptom when running the auto lock hubs on a plow truck due to the constant forward/backward direction change. When you reverse, the auto hubs briefly unlock and then relock, thus placing some slack in the front driveline which will be transmitted through the drivetrain and can appear to stem from the T-case or front drive shaft. Auto hubs are never a good idea on a plow truck and should definitely be changed over to manuals.
> 
> Run it long enough and you'll be forced too anyway as the autos will wear out/break anyway.


B&B - Wow your good!! Thanks for the info. Do you have a certain brand of hubs you prefer over another? I've never changed over hubs before and I don't have access to a lift. Is this something I can tackle myself or should I just bring it down to a shop? My mechanical abilities are decent but I'm by no means a ASE certified tech.

Am I beating on anything else using the auto hubs or can I as you say run it long enough until the hubs break. I just don't want to turn a $300 job into a $1300 job.

Thanks again for your help everyone!!


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## the new boss 92 (Nov 29, 2008)

i agree auto locking hubs suck


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## JustinD (Jan 14, 2008)

I had a 91 K5 Blazer, I switched over to the Warn all brass hubs, not the cheesy plastic ones, the never gave me an issue.


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## 2COR517 (Oct 23, 2008)

Do they still make the Selectro hubs? You could grab them with your whole hand with gloves on.


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## B&B (Nov 4, 2006)

Dondo;933253 said:


> B&B - Wow your good!! Thanks for the info. Do you have a certain brand of hubs you prefer over another? I've never changed over hubs before and I don't have access to a lift. Is this something I can tackle myself or should I just bring it down to a shop? My mechanical abilities are decent but I'm by no means a ASE certified tech.
> 
> Am I beating on anything else using the auto hubs or can I as you say run it long enough until the hubs break. I just don't want to turn a $300 job into a $1300 job.
> 
> Thanks again for your help everyone!!


Ditch the auto hubs asap before they leave you stuck, they were never intended to plow with and will not hold up. They won't damage anything else per say if one does let go, except for your customer reliability reputation. Warn is my preferred brand name for replacements. Either standard or the premiums. The only difference between the two is the style of the hub dial, the internal components that matter are the same.

If you have any mechanical skills at all you can swap them yourself. Just need a Torx bit, a small set of needle nose pliers, a small screwdriver and a set of snap ring pliers...and about 1/2 of your time. No need to even raise the wheels off the ground. Install paperwork will come with the new hubs to guide you along also.


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## welded wrenches (Oct 19, 2004)

*auto-lock =auto stuck=aaahelp*

hi ya,i ll second that b&b auto lock hubs is more like auto stuck n call aaa ..go manual lock hubs..which ever aftermarketbrand. warn ,super winch ...anykind is better than them auto lock hubs.i mean click n clack not locked n stuck again..lol..i wish i had a set chevy factory oem spicer lockouts..i hope you get your new lockouts insoon..heres a link web site for tons repair info on older chevy trucks www.chuckschevypages.com have a good day


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## Thermos017 (Dec 16, 2009)

welded wrenches;936580 said:


> ...heres a link web site for tons repair info on older chevy trucks www.chuckschevypages.com have a good day


I think the link you intended was www.chuckschevytruckpages.com (note the "truck" added in the link).


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## RichG53 (Sep 16, 2008)

Do you have any site like this for 2000 and up ???? It would be very helpful... 
Thanks !!!


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## Dondo (Dec 8, 2009)

I am going with the Warn hubs. The local "Red Letter Dealer" in my area has them in stock. He says I also need the conversion kit for the 88-90 K5's. He wants $150 for everything I thought that wasn't to bad. Plus it's only 18 degrees outside right now and I have no garage access. He only wants another $25 to install them. So as of Thursday for a total of $175 I will have the manual hubs on. 

Thank you everyone for all the help with this. 

New Boss - Sorry about hopping in on the forum. Hope you mke out as well as I did with your Bad Clunk.

Happy New Year


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## B&B (Nov 4, 2006)

Dondo;942467 said:


> He says I also need the conversion kit for the 88-90 K5's.
> Happy New Year


 Yours shouldn't need the spindle nut conversion kit. It's only needed when replacing auto hubs that are held on with three attaching screws. Yours should have six, thus it wouldn't be required.

See? It's getting less expensive all the time.


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## Oriole (Jan 4, 2010)

Does these auto hubs also apply to the newer OBS chevys, my 97 extended cab is doing the same clunk in reverse deal, not sure where the problem is exactly though.


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## B&B (Nov 4, 2006)

Oriole;942982 said:


> Does these auto hubs also apply to the newer OBS chevys, my 97 extended cab is doing the same clunk in reverse deal, not sure where the problem is exactly though.


No it wouldn't apply in the aspect that were discussing as you're '97 has no lockout hubs at the wheel hubs. Yours would be more common to a worn U-joint or wear/age in either of the diff's depending on age.


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## Dondo (Dec 8, 2009)

B&B;942933 said:


> Yours shouldn't need the spindle nut conversion kit. It's only needed when replacing auto hubs that are held on with three attaching screws. Yours should have six, thus it wouldn't be required.
> 
> See? It's getting less expensive all the time.


B&B - You are amazing!  Is Chevy Diagnostics just a hobby or do you work for GM or something? I had a couple "chevy guys" drive the truck to see if they could help me out and I got about 4 different answers as to what was wrong . None of them were correct. But, you diagnosed the problem from a half as$ desription via a forum and nailed the problem dead on.

Thanks again!!


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## Dondo (Dec 8, 2009)

B&B;943095 said:


> No it wouldn't apply in the aspect that were discussing as you're '97 has no lockout hubs at the wheel hubs. Yours would be more common to a worn U-joint or wear/age in either of the diff's depending on age.


B&B - I just sent you a PM.


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## Dondo (Dec 8, 2009)

Truck is getting the new hubs as we speak. I will let you know how I make out since I might get some snow tonight and a chance to test the new hubs.

Thanks again!


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## Dondo (Dec 8, 2009)

Not really enough snow to plow yet alone need to be in 4 wheel drive but I just needed to go and try out the new hubs. 
They work perfectly now!! No transfer case bang going into reverse like before. 

B&B is da man!!:salute:


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## B&B (Nov 4, 2006)

Good to hear it's working for you Dan.


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## Dondo (Dec 8, 2009)

Check it out


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## Snowzilla (Oct 24, 2009)

My '89 was clunking in when in reverse after the first storm in December during some plowing. The culprit for me was the bolts which fasten the flange of the front driveshaft to the transfer case were loose.


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