Question about 1999 GMC Suburban

1 Answer

Bad Smell only when window is down...Smells like propane

I had full service done, Radiator,brake,engine,transmission and rear axle gear box oils replaced. 54,000 miles Was told everything looked good. Days later I was on the road for 2 hrs with ac running pulling boat and was about to clime hill so we turned off ac and rolled front windows down. A propane type smell hit us. Could not figure out smell and it would not go away. Only smell it when we are moving. Only smell it when window is down and we are moving. I brought it back to Chevy dealer and they said they think the rear axle gear box got very hot and created the smell and was released through the breathing tube. They think the gear box is going out.They replaced oil again. Was told once more the oil had no metal shaving and it looked good. My question; How hot can oil get before it starts to smell. Is it possible the gear box is going out...Or Help

Posted by on

  • Barefooth2o Aug 17, 2008

    The rear differential is the gear box I am talking about. They said they did a test on the cat. and exhaust system and it checked out OK!


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 5 achievements.


    An expert that has over 500 points.


    An expert who has answered 200 questions.

  • Expert
  • 298 Answers

No the ring and pinion seems ok from what you are wouldn't smell it up front while moving do to wind and what not,
oil can smell at low temps.
you may have an exhaust leak at an O2 sensor seal. or something relative to that.

Posted on Aug 17, 2008

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

I just bought a 2005 Jeep Liberty and there is a leak under the front end after sitting for a few hours. It's clear and blace in a few spots. They have checked it and all fluid levels are full and can

is car 4WD?
ok, is this your first car?
is this your first car with A/C? for first time ever using and A/C?
(btw front defrost mode uses A/C functions)

if pure water, its just A/C condesate, 100% normal all cars.
today cars have a wide variaty of new fangled fluids.
in the olden days we had tan, and green'
now its many.
toxic AF (antifreeze) green, pin, yellow, red, orange , etc. now.
Engine oil think goodness is just tan/brown or black
pull dip stick gander at the tip (THAT is your color today)
now the transmission, A./T automatic, it usually is pink, but can be
read or dark red. (if your year has a dip stick on A/t pull it and bingo your color is there)
then there is the leaking, (rare) window washers. (can be any color)
but is soaping to the touch.
last is M/t boxes. manual gear boxes,, and transfer case (4wd)
the they can be , clear to brown. my synthetic is clear but is very viscous, and smells sweat.
Some axles and transmissions have (gear boxes) have hypoid gear lube that is brown and stinks to high heaven.. nasty smell.
But this too can be different today, and be any color, from clear to purple to brown.
last is brake fluid, its always clear, but in large volume or old is amber.
it smells sweet. and sticky.
that is what we have today.

find your cars A/C condensate drip tube under car
and memorize that location, then when it leaks, you know.
its that.
on some cars its at passegers toes.
on my jeep its dead center, of car.

Mar 29, 2014 | 2005 Jeep Liberty Sport

1 Answer

Theres a smell of gear oil in the cab when driving.What could it be?

(1) motor oil only smells when its being burned.
(2) the output of the air ducts is in front of the gear shift area.
So, I'm thinking that you have an oil leak in the engine compartment (which may be dripping onto the exhaust system), and the oil has found a hot part of the engine/exhaust, and the smell of heated oil is wafting through the cabin air filter into the passenger compartment through the air ducts in the middle of the dash to just above the gear shift area.
If my theory is correct, you should be able to re-route the burned oil odor by changing the setting of your air ducts by changing the setting from its current setting to a "defrost-type" setting, wherein air entering the passenger compartment comes from the ducts below the windshield, rather then entering through the openings at the center of the console.
Ultimately, your fix will be to locate and resolve the oil leak.

Here's your list of possible culprits for the 1997 Nissan Pathfinder

Priority Action Part Type Cause
1 Inspect - Valve Cover Gasket -- Valve Cover Gasket Leaking Oil.
2 Inspect - Oil Filler Cap -- Oil Filler Cap Damaged or Missing.
3 Inspect - PCV Valve -- Plugged or Damaged PCV Valve.
4 Inspect - Oil Pan Gasket -- Leaking Oil Pan Gasket.
5 Inspect - Head Gasket -- Leaking Head Gasket.
6 Inspect - Oil Pump - divided O-ring or Oil Pump Gasket

If the odor really is gear oil (aka transmission fluid) and not motor oil, then there's a leak coming from the automatic transmission/manual transaxle.
Look under the transmission after the car has been parked awhile, and look for a reddish oil spot/blot/pool. transmission fluid is dyed red just for the purpose of differentiation from other automotive lubricants. You can assist the process of color differentiation by putting newspaper under the vehicle once it's been parked for the night.
Placing enough newspaper may also keep your Pathfinder from depositing a nearly-impossible-to-remove oil stain onto your garage floor overnight.
If you already have an oil stain on the floor, try a spray can of engine degreaser first. Citrus degreaser next.

Oct 20, 2011 | 1997 Nissan Pathfinder

1 Answer

Mazda 323 auto gear box when engine up to running temp and been driving for about 15 mins it keeps wanting to change gear culminating in the hold light flashing...and lumpy when slowing down or speeding...

You need a full service of the auto transmission. Check the oil condition for burnt smell.
The oil may be burnt out and fails to lubricate when temperature goes up.
But most likely the gear gaskets or gear teeth are worn out.

Mar 17, 2011 | 1994 Mazda 323

1 Answer

Transmission slipping when you first accelerate. Wondering if it could be something electrical. Please advise on what needs to be done.

you have an electrical gear box but it still works on oil presher and clutch/brake bands,,,if there slipping first check the gearbox oil is full and the colour of it,,it shouldbe red,,if its a dark brown and smells burnt you need to have the gearbox looked at,, do this sooner than later as the longer the box slips the more its going to cost you fixing it,,

Aug 28, 2010 | 1996 Volkswagen Jetta

1 Answer

Signs of transmission problems

The most reliable and tried and true method is to check the transmission oil. Check it for...
1. Correct level
2. Right colour: a nice light red. (or somtimes yellow) not brown
3. Smell, it should have a not unpleasant smell, if it smells 'bad', it is starting to break down and will attack the friction material on clutch packs and brake bands.
4. Remove the transmission oil pan and check it for flecks of friction material, metal filings and pieces of rubber.
If any of these things are present, you have, or will soon have a transmission failure. The whine could be the transmission oil pump, the gear set is known to to come incontact with the pump body causing whining noises and creating metal filings which cause the transmission valves to stick..

Apr 08, 2010 | 2009 Honda CR-V

2 Answers

Numerous issues with my 95 Jeep Grand Cherokee Loredo

The oil leaks, just keep the levels full. The engine mounts, unless they are torn apart, let them ride. The front axles, let them ride, its going to cost the same now or later, they need to be replaced. I would FIX the coolant leak. ASAP. once you overheat or do damage to the engine, the whole truck is scrap.

Oct 22, 2009 | 1995 Jeep Grand Cherokee

5 Answers

Rear direrintial

The rear diff. turns the rear wheels. It is located in the middle of the rear axle. It won't last long if you ignore it. May just need dearing's but if it is driven the cog wheels will grind to dust or drop off this can cause the rear axle to seize up and can be a danger because the back wheels will lock up. If you are going to fix it yourself let me know and I will be able to guide you through the process

Aug 10, 2009 | Chevrolet Silverado 2500 Cars & Trucks

2 Answers

Slow pick-up, high rpm

It seems as though the Transmission clutches are slipping if it's an automatic or the clutch is worn if it's a standard. If it's an automatic transmission check the Transmission oil it should be clean and no burnt smell. You will easily recognize burnt oil by it's nasty smell.

Jul 03, 2009 | 1996 Hyundai Accent

1 Answer


if its manual sounds like your clutch could be slipping does car smell of burt clutch?
check cluth adjustment
may need new clutch
do stall test with hand brake on, foot (heel-toe) on brake and accel pedal to about 2000rpm then let out clutch and car should stall if engine revs go down and engine still runs but you can rev causing slip and you will now smell what slipping burnt clutch is replace it.

if its auto check trans oil level and what does it look like red-good
darker red to black-bad often smells burnt also possibly new trans required.

May 31, 2009 | 2000 Toyota Celica

4 Answers

Need to put oil and fluids into honda and don't know witch is for what

one of the best ways to tell what is what is to open the one that you want to add first and smell it...then remove the cap of the one you think it is and smell that ...

Mar 10, 2009 | 2002 Honda Accord

Not finding what you are looking for?
1999 GMC Suburban Logo

364 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts


Level 3 Expert

70346 Answers


Level 3 Expert

1311 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22041 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides