2003 Chevy Tahoe Question

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  #1  
Old 10-30-10, 05:32 PM
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2003 Chevy Tahoe Question

Pls help advise and educate me. I am a car dummy. I do try to do routine maintenance on cars.

2003 Chevy Tahoe about 115K miles.

Car was taken to a national auto and tire store today to rotate tires. Drop car off and get a tel call about an hour later while running some errands. the store manager says I have leak in rear differential due to bad seal.

First off , what exactly is rear differential? I have not noticed any leak in carport. They propose to replace seal, drain fluid and replace for about $100. Is price reasonable?

and how often should transmission fluid be changed out on a car this age?

thank you for your reply.

 
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  #2  
Old 10-31-10, 05:31 PM
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rear differential is a device that accepts rotation from engine, via driveshaft, and distributes it to the rear wheels. it has some other, more complex function, but in a nutshell, that's it.
you should have solid rear axle with differential built in. it is that large round box in the center of the rear axle.
it has a drain plug dead in the bottom of it and a refill plug on the upper part of the long extension, where driveshaft enters differential.
schedule says every 60 000 miles, or 48 mths, whatever comes first. you are long due.
take a flashlite and get underneath the car, from the rear end. differential has round, spherical cover, and cover has a seal that seals differential fluid inside. most likely, you will notice some sipping around the seal perimeter. maybe take a rag and clean dust and slime for better look. from this point on, you need to assess the size of leak.
as you have noticed, there are 10 or 12 bolts that hold cover in place. drain plug is dead in the bottom of differential, 3/8 inch square hole for socket wrench. you can place a drain pan underneath, drain fluid out, remove bolts that hold cover in place, and remove the seal. seal will cost you around 10 bucks any parts store. same time, while you have cover off and drain plug removed, spray gears inside with some cleaner, like carb cleaner, and slime will drain down into the pan.
get a rag, reach inside the differential, and wipe everything you can reach clean, esp down in the housing bottom.
make sure that cover and seal seat are perfectly clean and no old seal material is left. buy some blue rtv silicone, apply to both seal sides, place it back on the seal, place cover back on, tighten bolts in criss-cross pattern.
to get to the refill plug, you will have to have vehicle raised up some, on the rear axle, and secured there, with jackstand. refill plug is on the passenger side of the driveshaft exptension, on the top of it, there's flat recess in the housing. same 3/8 square hole plug. remove it, and refill with most expensive synthetic oil in proper weight you can buy for your car. i use Amsoil for this purpose, but any good synth will do. level must be 3-4 mm below the drain plug lower edge. they sell gear oil in squirt bottles, it will fit directly into the hole.
takes 2 liters, i think. but you can check at any parts store or call dealer.
your cost will be about 30 bucks and maybe 25 minutes of time even for a rookie.
 
  #3  
Old 11-01-10, 09:28 AM
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ukrbyk

first off, thanks for your detailed reply.

as mentioned, I have not seen any sign of leak like a puddle in my carport where car is normally parked in the evening. Should I? I don't want to be snookered.

I am not mechanically inclined nor do I have the tools.

So is $100 a fair price to replace seal, drain, and refill?

I hope you see this and thanks again.

 
  #4  
Old 11-01-10, 10:02 AM
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If that is really the problem...an independent shop would probably do it for about $50 or so labor + parts. Might work out to close to the same. Everyone has to pay hazmat and disposal fees, taxes, etc.

Example...national brake chain quoted me almost $450 for front brake rotor and pad replacement on my SUV using their brand parts. Local independent shop charged $240 using premium parts. Dropped it off early in the morning...had it back 2 hrs later.

As ukrbyk said though..w/o evidence of a leak..it's just routine maintenance. A small leak my be blowing away when you drive as the diff warms up and the fluid thins a bit and leaks.

I have a small leak in a differential seal on the above SUV (it has independent rear suspension), replacing it requires removing rear axles and more. Cost was almost $500 for repair as I remember. I check the fluid level every 6 months or so and it's been working fine for almost 100K miles...I think I've added fluid twice?

If you don't have the tools or time...it's up to you whether it's worth it. Since you have primary rear wheel drive (even if it's a 4WD)...if it leaks out enough, you could be looking at $1000 or more to repair the differential.
 
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Old 11-01-10, 11:34 AM
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gunguy

I think I will get another opinion or at least have it placed on a lift and take a look myself.

Just to be clear, I should wipe the rear differential down with a towel? Should the fluid level be checked? or is that even possible?

thank you for your reply. it is much appreciated.

 
  #6  
Old 11-01-10, 12:06 PM
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You can probably do it by just sliding under and looking. Actually dust and such is kind of helpful when looking for a leak..you'll see the dark discoloration...though diffs normally will leak at a low point. Think of it as a bucket laying on it's side with a lid that isn't completely sealed. It may have a leak 1/2 way up the side but it will run to the bottom. If you blow a strong wind past the leak it will spray backwards.

As was said (I don't know your vehicle) there may be an inspection port and a fill port. The ones I have messed with just have a plug that is removed about 1/2 way up on the cover or case and if the level is w/in about 1/4-1/2" of the threads..its good.

Again...as was said earlier...a few dollars now could save thousands later. Look in your manual for change intervals..if you don't know when the last was..then start fresh. I know money is tight everywhere..but a dead vehicle on the side of the road with $1000 or more in needed repairs is even worse.
 
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Old 11-01-10, 01:06 PM
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TigerDunes,

(Quote) Car was taken to a national auto and tire store today

Quote) Pls help advise and educate me. I am a car dummy.

(Quote) as mentioned, I have not seen any sign of leak like a puddle in my carport where car is normally parked in the evening.

(Quote) I am not mechanically inclined nor do I have the tools.

Tiger,

Your above quotes speak for themselves. The national auto and tire store is trying to capalitizing on the above, and stick it to you where the sun doesn’t shine.

Tell the individual who told you that you need a seal, that you are not going ahead with the job, until he answers a few questions from a friend of yours.

Then have him log onto this forum (on your behalf) I would like to speak to him. .
 
  #8  
Old 11-04-10, 09:39 PM
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Originally Posted by TigerDunes View Post
ukrbyk

first off, thanks for your detailed reply.

as mentioned, I have not seen any sign of leak like a puddle in my carport where car is normally parked in the evening. Should I? I don't want to be snookered.

I am not mechanically inclined nor do I have the tools.

So is $100 a fair price to replace seal, drain, and refill?

I hope you see this and thanks again.

you welcome. gunguy did excellent job helping you out. there is no separate port to check on fluid level. it is checked through refill plug, with - yes - finger tip.
should you have puddle on the floor, your rear axle, by now, would have been howling very loud. them hypoid gears do not like being without lubricant. and then they go bad, very fast.
you, most likely, have sipping. well, personally, for me - it is poc to diy. you sound like a "find a better place to do it for me" kind of person. so yes, shop around and settle for comfortable amount. keep in mind, going places, you taking huge chances of
1. having ****ty job done, as you always get what you paid for
2. getting under sales pressure to make you fork for other "repairs". they smell a rookie from a mile away.
i'd say, for you, and if it's a reputable shop with warranty, 100 bucks is ok. IF IT LEAKS. my silverado decided to develop sipping around front oil pan seal. i cleaned it good with brake cleaner, and sealed, on the outside, with red silicone. that was a year ago, still not a drop. you see, this is why this is do it yourself forum, not "where doo i find a cheap mechanic" forum. no offense.
 
  #9  
Old 11-17-10, 07:30 AM
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I thought I would provide an update after everyone was so nice in responding and advising.

I did have transmission fluid drained and replaced by another company. I was at 116K miles and could not find where this had been done.

I asked other company to check rear diff fluid and they saw no leak and fluid level was checked and was OK.

So at what point should rear diff fluid be changed out?

thanks
 
  #10  
Old 11-17-10, 09:44 AM
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If you would ask the corner quick lube they would tell you to have it changed today. Some dealers can be just as bad these days also. Most are hungry. Best to follow what GM suggests in their manual, and if they don't mention it then probably every 40K makes sense. Lots of people never change it, but then again many never change anything until it breaks, and then complain after.
 
  #11  
Old 11-17-10, 10:31 AM
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Just for info, I did check my owner's manual thoroughly and no mention of rear differential or fluid change. I suppose I will call dealer or change it on next oil change.

TD
 
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