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Have a noise when cornering at slow speeds. Have read this can be caused by positraction lube needing replacement (clutches slipping). Can I just add a bottle of positraction additive or do I need to drain? If draining needed, what is best method? As you can see, I'm no mechanic.
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Re: noise in differential
Joe----
The best thing to do would be to drain the differential fluid. Then add 2 bottles of GM positraction additive and fill the remaining with GM positraction fluid. However, you can just add the additive to your existing fluid to see if it helps the problem. You may have to remove some fluid, first. I would recommend adding 2 bottles of the additive.In Appreciation of John Hinckley -
Re: noise in differential
Joe,
I agree with Joe Lucia, with a slight twist.
You can use a suction gun, easily purchased at most auto parts stores, to remove the fluid from your differential. If you have a 63-82, access is easier with the rear of the car on jack stands, the wheels not touching the ground, and the spare tire assembly removed. The assembly can stay if you wish, i.e. it's never been off the car and you want to leave it.
Remove the plug, and suction out as much fluid as you can. You'll hear it when it's empty. Then put in the 2 bottles of GM positraction additive available from your Chevy dealer. Fill it with GM fluid if you wish, but having done that a couple of times in my 71, I switched this time. I went with Red Line 75W-90 as recommended by them for differentials, and mine is MUCH quieter than ever before. And this is even after changing the fluid every 10,000 miles! I highly recommend it.
After swapping fluid, find a nearby parking lot. Slowly drive in clockwise circles for a few minutes, then counter-clockwise. This will help free any sticky posi clutches, and get the new fluid between them.
Good Luck! Patrick HulstVice-Chairman (West), Michigan Chapter NCRS
71 "deer modified" coupe
72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
2008 coupe
Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code.Comment
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Re: noise in differential
Patrick---
I definitely agree with you on the synthetic. Some folks are skeptical of synthetics or don't believe that they justify the cost. That's why I usually recommend the GM lubricant, because it's the only non-synthetic that I would use or recommend. However, for those willing to use synthetics, like me, I believe that it's the way to go. I use synthetic lubricants for engine, trans, differential, and all grease applications except steering box. Manual transmissions, in particular, operate cooler and smoother with synthetic lubricants.In Appreciation of John HinckleyComment
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Re: noise in differential
I like the redline stuff too!Comment
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Re: noise in differential
Didn't say what year you had, but the later Shark car's have superior 'care & feeding' documentation in the form of the Chassis Service and Chassis Overhaul Manuals. In addition to job detail, you'll find info on general theory of operation as well as diagnosis tips (noises, etc.) in these books.
You say you're no mechanic and bless you for being up front. Whether you turn your own wrench or not makes little difference. The guys who worked on these cars new are mostly retired (or pushing daisy) and doing some level of due diligence up front before you dive in and/or throw money at a problem can make a world of difference in the result.
I encourage everyone who owns one of these classic cars to invest in a support library to protect and enhance their investment. Also, if you don't want to buy the tool to suck your diff, you'll find most good oil change shops that also do tranny work have a suction pump for rear end jobs....Comment
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Re: noise in differential
Joe, Are you using the Redline as well? If so what grade are you using? I am looking to use the Redline in my newly rebuilt 4spd after the parts get a chance to "bed-in" a little.
Alex
'66 A/C CoupeComment
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