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Discussion Starter · #1 ·
Ok, i'm just wondering if anyone else has ever experienced these sounds, or if it's common and not a problem at all.

I have been getting two different sounds lately.

Sound 1: When I shift my truck into reverse, I hear almost a crackling sound. It sounds like it's coming from the trasnfer case. It's not very loud, I can't even here it with the windows up, but it's there.

Sound 2: At slower speeds, like in a residential area, my driveshaft makes a clunking sound when it shifts from 1st, into 2nd gear. I'm thinking maybe my u-joints are worn?? Or i need a different shim in there with a higher degree of an angle?

Has anyone else experienced these sound with their lifted truck? Anyone out there with 10" of suspension who noticed any of this?

Thanks
 

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Discussion Starter · #3 ·
Did you take it to a dealer, or your local mechanic? And about how much would new u-joints be?

Thanks for the reply
 

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Discussion Starter · #4 ·
no leaks

there is a rusted tube looking thing that is inserted into the rear of the transfer case, i hope i'm describing this ok. It attaches the end of the rear driveline to the transfer case, and it sticks out a little bit.

i crawled under my friends dad's bone stock z71, and there is about a 1 1/2" gap between the top of his driveshaft and the transfer case.

i crawled under my friends z71 with a 3" body, ford keys and a 1" block, and the gap was around 2 1/2".

i crawled under mine, and the gap is like 3 1/2". This rusted tube sticks out a lot more than my friends and his dads.

How do they actually lengthen the driveline? and what is the cost of this?
 

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u-joints are fairly cheap. I replaced all the u-joints on my front driveshaft (did the work myself so i only paid for parts) and it cost me about 40 bucks for the 3 u-joints. If im understanding the way you explaining it correctly, the rusted part is the end of the driveshaft, and there is a slip yolk at the end of it that connects to the transfer case. When you lift the truck the slip yolk slides apart from the driveshaft to accomidate for the extra distance caused by the lift. If you have a 10" lift and didn't do any sort of driveline extension then that might be your problem. The sound that its making sounds a lot like a bad u-joint. The u-joints are fairly easy to replace on your own if you have a bench vice and some common tools. I hope i helped, and if i said anything that sounds wrong please feel free to correct me
 

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Discussion Starter · #6 ·
Yeah, sounds right, I think i'm talking about the slip yolk.
 

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I think the first one sounds like ujoints. That said, if your driveshaft is stock with that much lift, it might have caused your ujoints to take a dump, especially on that new of a truck, they're supposed last alot longer. I think the clunk could be slip yoke.
 

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As has been said previously, check your u-joints. Especially the axle end. Im guessing you didnt rotate your pinion up with your lift? 10" with stock pinion angles can cause nasty vibes and noises.
 

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Discussion Starter · #10 ·
yeah, i don't know of any shops that specialize in drivelines here in Fresno.

I just looked under the rear of my truck, and I realized I don't have a shim or angled blocks or anything. So there's my problem. I just have 10" leaf springs with the stock 2" blocks. My pinion angle isn't horrible, but i think it's just enough to cause the clunking sound. I'm getting absolutely no vibrations at any speed.

I'll make a visit to full throttle and ask them about getting a shim in there, or taking out the stock block and throwing in an angled one. If i remember correctly, i asked them about lengthened drivelines. They told me i didn't have to lengthen it in the back, unless it's lifted 12" or over. Also, I don't have auto-trac, and I'm running my stock front driveline with no problems. They said i don't need a new front driveline, unless I go over 10" in the front.
 

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Discussion Starter · #12 ·
Ok, I had my friend come over and I started my truck with him standing at the rear, near the rear axle. I shifted it straight from park, into reverse, and sure enough, it made the clicking sound. He is positive it's my U-joints.

So, what to do now. I obviously need to correct my pinion angle to prevent this from happening every 20k miles. So, my backend is about an inch higher than the front. I'm thinking I can take out the stock 2" block, and put in a 1" angled block, with new bolts and u joints, and that'll help solve the problem. I'm not too sure about lengthening my driveshaft though... I don't know of any shops that do that around here, unless full throttle can. Also, does lengthening the driveshaft weaken it at all?

My friends installed u-joints on a 4x4 ford ranger before, so i think he can help me with mine. How can i tell if it's the rear u-joints, on the pinion side, or if it's the front u-joints on the tranfer case side? When I'm in the cab, it sounds like it's coming from right under me, like around the tranfer case, but my friend said he thought it was coming from the rear end.

I'm thinking if i buy $40 new u-joints, and $70 new angled blocks with the bolts and u-joints, I'll hopefully solve my problem, and it won't get too expensive.

What do you guys all think?
 

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I think it sounds like both ujoints, and I would probably replace them both even if one was still good, because it won't be for long.
 

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Discussion Starter · #14 ·
is the upper u-joint, closest to the transfer case connected at all with the slip yolk? In otherwords, do I have to replace the slip yolk too?? Also if i do replace the u-joints by myself, is there anyway I could screw up the tranfer case??

I'm sorry, I know absolutely nothing about axles or drivelines or transmissions, so thanks for the help.
 

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Nope, the slip yolk is connected to the unjoint just like the rest of the driveshaft, so it doesn't have to be replaced.

Nah, theres no way to screw up the tcase. Its an easy job. Just take out the shaft when you do it :crazy:

Search for ujoints, someone around here wrote a mini howto on them. Next time I have to replace some I'll write a howto with pictures and stuff.
 

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Drive Line Service of Fresno
2785 South Golden State Blvd.
Fresno, CA. 93725
800-824-0706
fax-559-266-4355

^ Great Shop


Anyway, you need to get your shaft lengthened. What is happening is there is not enough support on the slip yolk which causes it to kind of hang off the end of the output shaft of the t-case. This causes a slight vibration which kills the u-joint up there and also causes lash in the slip yolk which is most likly the clicking you hear. The thump is most likely a u-joint but a click should be the slip yolk.

If you don't want to do this and just want to change joints, it's not hard. Pull the shaft and pull the clips off the bearing caps and then just BFH them out and BFH the new ones in and put new clips on and re-install shaft.
 

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Discussion Starter · #17 ·
Thanks for the reference Jason. I'll check them out this week or next.
 

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Discussion Starter · #18 ·
I know this thread is old, but i finally got some pics of the angles...

What are your opinions?

Right now i have the stock 2" block, and I am really tempted to go buy a 1" angled block to correct the angle. Should I still have it lengthened? And how soon should i get new u-bolts??






Thanks in advance
Alden
 

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I think you meant to say: How long should go until I put in new U-JOINTS? Not U-BOLTS.
 
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