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Discussion Starter · #1 ·
I just bought a used 2003 Chevy suburban and it was working good, I like to replace certain parts to make sure it lasts a long time and I don't have to worry. I've already planned on replacing the spark plugs, alternator, belts and oil. But before I could get to any of that, today while driving, my husband noticed it was delaying on the gas, than as we turned a corner, there was a clunking noise. Now when we shift gears, its an audibly loud clunk. So in your opinion, should I check the transmission or is it something else? And all the fluids are full, I check those all the time, One of my good habits.
 

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First of all don't replace parts that don't need to be replaced such as the alternator. If your alternator tests good don't touch it as it may have a lot of life left in it.

When your husband noticed it was delaying while on the gas were the RPM's jumping up? that would indicate transmission slippage.

Is the transmission fluid very dark brown or black and does it smelled burned? how many miles are on it and has the transmission been serviced before?

The big thing about fluids is just checking them is not enough they need to be serviced at decent intervals, for me I personally service transmissions every 35,000 miles with a drain/fill and a new filter, I do not care what anyone says about going 100,000 miles or lifetime fluids it is all bs do not listen to them if you want your stuff to last.
 

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Sunny, while your checking the transmission, check the condition of the u-joints, the noise could be coming from them.
And I agree with @Furious , don't change parts until they fail.
 

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sometimes the slip yoke binds up and then when it slips you will hear a clunk. a little bit of grease will solve that problem but the driveshaft needs to be removed so the yoke can be greased. this is the part that connects the driveshaft to the transmission or if it's a split driveshaft, the slip yoke will be after the carrier bearing but the procedure is the same.

however this sound shouldn't be heard all the time but more like when going from reverse to drive. it's the same kind of sound as a bad universal joint.

take care!

Al
 

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When I purchase a vehicle that old, I change all the fluids to get a feel for what the overall condition is.
Then after that change at normal intervals, because you never know what was done before.
 

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2000 Silverado Z71 4x4 5.3L 460k+ miles w/ GM rebuilt motor and trans
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Are you feeling the clunk as well as hearing it?
 

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Discussion Starter · #7 ·
So I know it's probably not what alot of people suggest doing, but I do like to replace the alternator Everytime, but I do keep the old one as a backup Incase it ever does fail. The fluids are serviced on a routine, we have a loyal mechanic who does it for me and it doesn't cost a bunch. The sound is kinda metallic and can be well heard when shifting from reverse to drive and you can feel the truck jump a little. We have made an appointment for the transmission to be checked. And the u joints were checked before we bought it. Hopefully the tranny check will shed some light, but thank you everyone, for pointing us in the right direction.
 

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2000 Silverado Z71 4x4 5.3L 460k+ miles w/ GM rebuilt motor and trans
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Sounds like a sloppy rear diff and/or u-joints to me. The loud slap is the slop being taken up. My a Silverado does it real bad.
 

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Sunny, not my place to suggest how you spend your money; but the original alternator on your truck is probably better than any new one available today.
If you have some alternator paranoia, but a new one and hold it as the backup, just my 2 cents.
 

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I have to agree with RayVoy the original alternator is probably better than any new one. While I have had good luck with Duralast Alternators and you can't go wrong with their lifetime warranty the truth is the original ones were built better than aftermarket.

You could do as mentioned and buy one to hold on to but I would not replace an alternator that is working correctly and tests good.

If it ain't broke, don't fix it because you can cause yourself a huge headache with some aftermarket products such as alternators or ac compressors.
 

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let us know what you find out. I also agree with the alternator replacement. since the Universal joints were checked before you bought it, there a good chance it is the slip yoke and some grease will fix it.

keep us updated.
 

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2012 Silverado 2WD, LT, LMG engine, All stock. 84,000 miles. A Florida truck, zero rust.
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The last time I had an alternator go out was on a 1985 K car in 1992. Nine different vehicles since then between the wife and I.
 
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Discussion Starter · #13 ·
Hey everyone, so just got back from the transmission check and it was both of them actually, the yoke did need greased but the mechanic also said the transmission was on it's last leg, so we are in the process of replacing the transmission. And than we'll get the other greased. Thank you everyone for the help. Luckily the dealership that sold us the truck is working with us to help pay for half of the transmission bill, since they didn't tell us it was bad. But at least now we know, and it's getting fixed.
 
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