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DIY – Rear Axle / Differential oil change, with pics – for FAQ

DIY: Changing the oil in a base C6 rear axle / differential

If you are experiencing the common differential chatter noise on turns when cold (rubbing,

scraping, clunking, grinding or chatter sound), changing the differential lubricant will rid the

noise instantly, at least after doing a few figure 8's with the new lubricant in place.

For some, a simple differential lube change has proven to be the cure for many thousands of

miles, and for others, it has only helped for just a few thousand miles. If you prefer to avoid the

dealership and wish to take immediate action, change your differential fluid and you will get rid

of the chatter noise for likely up to a few thousand miles minimum if not much more. It's a

good first step in any case.

Overall, changing the oil in a base C6 rear axle / differential is very easy. If it’s your first time,

this DIY article will at least give you an idea of what to expect.

This refers to base C6s only. Z06s have differential coolers (base C6's do not) and require a bit

more effort. Z06s and export vehicles have different axle oil capacities than the base C6 as

well.

First, run the car a while to get the axle oil warm. I ran my car about 40 miles. When I got

back, the axle case was quite hot to the touch. 20 minutes after shutting off the engine, the

mufflers were finally cool but the axle case was still hot. With this in mind, it is a good idea to

wait about a half hour after shutting off the engine until the exhaust system cools down so you

do not severely burn yourself… the axle and axle oil will still be very warm for good drainage.

You’ll need to get the car up off the ground a bit as in photos, but keep car LEVEL. First choice

would be to use a real lift. Second choice, back the car up on Race Ramps and then jack the

front end in order to level the car. Last choice (most laborious), jack the car from both front

and rear.

Since you need to access the rear axle from the rear, you cannot block the rear with a jack. I

had initially tried to use my 4-point jack system, but was not able to access the axle plugs with

the rear jack and cross member adapter in the way. I had to add stands under the rear puck

locations and then remove the rear jack and cross member adapter. I then added two extra

screw jacks under the rear “preferred” jacking locations for extra support and safety. This

Summary of content (20 pages)

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DIY – Rear Axle / Differential oil change, with pics – for FAQ DIY: Changing the oil in a base C6 rear axle / differential If you are experiencing the common differential chatter noise on turns when cold (rubbing, scraping, clunking, grinding or chatter sound), changing the differential lubricant will rid the noise instantly, at least after doing a few figure 8's with the new lubricant in place.
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worked out fine. But next time I think I’ll try backing up on ramps… would be easier. The axle case has two plugs that must be removed… a fill plug and drain plug. The fill plug is on the rear vertical side of the case, the drain plug is on the bottom horizontal side of the case. Both plugs exist on the right half of the case (passenger side). Both plugs are identical in size / type.
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Put some cardboard down on the floor and have some rags on hand as you will inevitably spill / splash some oil. Place a drain pan directly under the drain and fill plugs. Clean the areas around both plugs. Using a 3/8” drive swivel arm socket wrench and 10mm allen socket of about 1 – ¾” total length (as shown), loosen and remove the fill plug.
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socket handle for leverage. Both my plugs did not require much effort to loosen… pipe was not needed. Next, loosen and remove the drain plug. The oil will come blasting out and may splash in the pan so shield your face. Allow the axle to drain for a while. Mine was still dripping 12 hours later. Clean the drain plug and area around the drain hole and install drain plug. Torque to 35 Nm or 26 lb/ft. I chose to torque by hand… basically just got it nice and snug. Do not overtighten.
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good “feel” for what it should be, then do your best to apply that same “feel” to the fill plug using your regular socket wrench. Time to refill the axle: IMPORTANT: Read the latest GM TSB regarding rear axle chatter to determine which GM gear oil / additive and amounts you should be using. This info has changed over the years and is subject to further periodic change. The latest axle TSB (as well as previous axle TSBs) can be found in post #2 of this thread: http://forums .corvetteforum.com/show...
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I guess you’d need a pump of some type to really empty the entire bottle into the axle... but not necessary because whatever oil does not make it into the axle can be saved for the next fluid change. Note: I am holding the bottle upside down in the photo – was just posing in that shot – bottle nozzle should be as low as you can get it with relation to the rest of the bottle. Add oil to the differential until oil starts dripping out of the axle oil fill hole.
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an important step so do not overlook it. Thanks to the forum and its members for much of the info in this DIY post! Note: I was just alerted by member Paulct that the axle drain plug on 2005 models (at least on his 2005) sits above the leaf spring so that you cannot get an allen wrench straight in from below. The spring is in the way. An L-shaped allen wrench tool must be used so that it can be pivoted above the leaf spring.
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Last edited by Vet; 07-23-2008 at 10:59 AM.
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calemasters): Date: 01-09-2008 TSB: #07-04-20-002A Document ID# 2048181 2005 - 2008 Chevrolet Corvette My Corvette Photos Member Since: Sep 2004 Location: Long Island NY Subject: Rear Axle Clunk and/or Chatter Type Noise on Turns (Drain/Refill Rear Differential Fluid) #07-04-20002A - (01/09/2008) Models: 2004-2008 Cadillac XLR (Including V-Series and Export) 2005-2008 Chevrolet Corvette (Including Z06 and Export) This bulletin is being revised to change the fluid recommendation and to remove the requireme
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bent tip screwdriver, remove the quick connect fitting retaining ring (3) from the quick connect fitting (4) and discard the retaining ring. 4.2. Remove the differential cooler inlet pipe from the differential nut. Drain the fluid. Filling Procedure: If not equipped with a differential cooler, install the drain plug (1) and washer (2) to the differential. Tighten the differential drain plug to 35 N•m (26 lb ft). If equipped with a differential cooler: 2.1. Install a new retaining ring. 2.2.
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Raise the vehicle so the wheels are about a foot off the floor. Make sure the wheels can spin freely without obstruction from the hoist or any nearby items. Start the vehicle and put the transmission in second gear. Slowly accelerate to 10 mph and hold this speed for one minute. Turn the vehicle off. Raise the vehicle. Check the fluid level in the differential. Add fluid until the recommended level is reached. Lower the vehicle.
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Clean any dirt from around the differential drain plug. Remove the drain plug and washer from the differential. Drain the fluid. Install the drain plug and washer to the differential. Tighten the differential drain plug to 35 N·m (26 lb ft). Clean any dirt from around the differential fill plug. Remove the fill plug and washer from the differential.
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After clutch pack replacement use synthetic axle lubricant GM P/N 89021677 (Canadian P/N 89021678). and the appropriate amount of friction modifier additive P/N 01052358 (in Canada 992694). See fluid amounts listed below. Note 3: PRIOR TO INSTALLING THE FRICTION MODIFIER ADDITIVE FOR EITHER OF THE ABOVE REPAIRS THE BOTTLE MUST BE SHA KEN VIGOROUSLY FOR AT LEAST 1 MINUTE TO MIX THE ADDITIVE THOROUGHLY.
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Subject: Rear Axle Chatter Shudder On Turns keywords bind differential #PIP3559C - (10/13/2006) Document ID# 1866944 2006 Chevrolet Corvette 2004 - 2007 Cadillac XLR 2006 - 2007 Cadillac XLR-V 1999 - 2007 Chevrolet Corvette, Corvette Z06 The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI. Condition/Concern: Rear axle chatter or shudder on turns on Chevrolet Corvette and Cadillac XLR.
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fluid between the clutch plates. Fluid capacity: 1999-2005 Corvette ALL Differential Lube: 1.69 qt (1.6L) Friction Modifier: 4 oz. (118 ml) 2006-2007 Base Corvette Differential Lube: 1.95 qt (1.85L) Friction Modifier: 5 oz. (148 ml) 2006-2007 Corvette Z06 Differential Lube: 2.70 qt (2.55L) Friction Modifier: 6.4 oz. (190 ml) Note 3: Export vehicles use 2.01 l (2.12 qt) synthetic axle lubricant GM P/N 12378261 (Canadian P/N 10953455) and approximately 150 ml (5.
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Corvette and Cadillac XLR. Recommendation/Instructions: If this is the first complaint for this condition flush and fill the rear axle with mineral based lubricant P/N 89021669 (in Canada 89021670) gear lube and 4 ounces of the friction modifier additive P/N 01052358 (in Canada 992694). If this is a repeat complaint or the condition persists after the flush and fill, replace the right and left rear axle clutch packs following published service procedures. After clutch pack replacement use 1.6 l (1.
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Find More Posts by Vet Add Vet to Your Contacts 09-12-2006, 03:00 AM #3 Vet CF Senior Member A few other bits of interesting info: My Corvette Photos Member Since: Sep 2004 Location: Long Island NY *Member vetteshop stated: “…in the past,I have replaced a bunch of clutch packs in the C5's, they have the same issue. Upon inspection of the removed clutch packs, they do not fail, they look brand new with no evidence of wear or damage.
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mechanically, it is more just an issue with the driver thinking something is wrong." *Member shopdog stated: "To do any good, the additive has to be worked in to the clutch packs. Since the diff is a splash system, it is sometimes hard for the slickum to find its way into the clutch packs before it settles out (isn't miscible in the diff oil). That's why the TSB says to drive the car in figure 8s immediately after adding it.