vcone1

Is vacuuming out the fluid ok ? Or is draining it better? The drain plug is very difficult to get out and my garage wants to vacuum it out.

WW7

I just drain mine out.. Tell your mechanic to take the pressure off the spring by raising the rear wheels instead of letting them hang , this moves the spring out of the way and makes the plug easier to get to.. This is probably the problem he's having getting to the plug....WW
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JasonAndrew

I had no issues doing mine on jack stands. As long as it doesn't break, a ball end allen wrench will be able to get in the hex of the plug.

cmonkey713

oemtech

No issue when I did it. But I have 4 post life.

LowRyter

take it the oil change joint, get the additive ......have them do it.

oemtech

Don't let them grease monkeys touch your car. Get 2 of 3 qts of GM differential fluid and do it yourself. Check the How To's if you don't know what todo or what is requiredm

Dano523

Not no, but Hell NO!!!

The correct fluid for the diff is straight Dextron LS Gear Oil 75W-90, part #88862624.

It will take about 2quarts without a diff cooler and about 3 quarts if you do have a diff cooler in the car. (buy 3 quarts either way, and its going to be about $25 a quart).

Best price I could just find,
https://www.ebay.com/i/162348966971?chn=ps&fl=a

You use something else, may end up with with the lockers in the diff loud as hell, but even some peg leg burn outs when the break away torque of the lockers is less than 100lbs.

To be blunt, the fluid for the diffs in the C6 was changed to Dextron LS Gear Oil 75W-90, part #88862624 a few years into the C6 production, since the old fluid was causing the diff lockers to be louder instead. Hence the reason that you want to use the Dextron LS Gear Oil 75W-90 is it is the correct compatible fluid for the LSD clutch pack material as well.


Now here is the glitch since most oil/lube places will not have the correct fluid, you would need to buy the correct fluid for them to use (again, about $75), and would be getting raped on the charge for them to change the fluid instead (read what money they my reduce the price for using the fluid you bring them, is going to be a joke).

So on that note, it much easy to change the fluid yourself, so you not raped by someone else doing it, with you supping the correct fluid instead.

LowRyter

what? why? It's just a drain and fill. And I don't even have jack to get under the car.

BTw- They did fine, I did buy the additive and they filled with the right weight synth fluid.

Took away the "clicking" in tight turns.

LowRyter

Yeah, I followed the owner's manual and bought the GM additive. Some here have mentioned a service bulletin and the fill you note. If I had known about the service bulletin, I would have followed it. But the service with GM additive worked fine for me (see above).

I don't think the whole bill was $75 including the GM additive I bought.

oemtech

Seen to many problems. Hell even my Cadillac dealer oil tech overfill my 2.0T by a quart.

joeking

I change mine myself and it is very easy to do but does take a little time.

Dano523

The wrong fluid can end up with lower break away values from the LSD clutches/faster wearing out, meaning having to tear the Diff apart to replace the packs, as well as the clutches becoming noisy again quickly as well.

Hence LSD clutch packs should have a 100ftlb break away value each side.


Bluntly, was a fad not long ago to use Redline fluid for the diff since it was slicker, ending up with lower clutch pack break away values/ peg leg burn outs, as well the diffs having to be pulled apart to replace the clutch packs that worn out prematurely as well.

Same goes for the Trans, since the T56 syncros discs ring pads require the correct fluid for them to work/ not wear out prematurely as well.

Nice Ride

I have used the same service tech at one of the Chevy dealers near me that sales and services lots of Corvettes for several years. I am going to have him do it. They have the lift, tools, training, and techniques I don't have in my garage. If you can DIY great, I want the job done right and agree it may cost more but it is my Corvette not the F150.

CadVette

Don't forget to go the nearest empty parking lot after the change and do about six figure eights to work the fluid into the clutch packs properly.

GOLD72

Starting with MY2009. The previous Mr. Badwrench factory fill was crap.

dmk0210

Just to make sure, there's no LS clutch additive necessary right?

The OM just says use the above mentioned gear oil.

dmk0210

I use one of these. You can use it to both pump the last bit of old fluid out, and of course use it to pump new fluid in (It attaches to the bottle of gear oil). I've had mine for a few years and used it to do oil changes of diffs and trans on a couple cars.

windyC6

what are the signs of the clutch packs "wearing out" due to the wrong fluid (to slippery) being used ??

mikeCsix

Draining and refill is best, the only thing you want to put into the differential is clean lubricant from a new bottle.