[ZL*Won]

Taking in the Z in for the 3K service. Planning to take to track soon. Thinking I need to change out rear diff fluid with Mobil 1 oil....any suggestions on exact type of rear diff fluid to use for track? Other suggestions? Thanks.

[cwebster]

Originally Posted by ZL*Won

Taking in the Z in for the 3K service. Planning to take to track soon. Thinking I need to change out rear diff fluid with Mobil 1 oil....any suggestions on exact type of rear diff fluid to use for track? Other suggestions? Thanks.

[Engine]

Definitely change the motor oil if you haven't done that already. Dealer should do that free the first few times. I changed mine after the first 600 and 1200 miles, then about every 6 drag strip visits. If the dealer changes it you'll get AC Delco dexos 1 5W30. When I changed it in Summer I used Amsoil Dexos 2 5W40. That's what you should go with if you take it on a road course.

From Amsoil Dealer:

Amsoil European Car Formula 5W-40 Improved ESP Synthetic Motor Oil
Case of 4 Gal: $119.00 (preferred pricing}
Product Code: AFL1G-CA

Amsoil Absolute Efficiency Oil Filter
Each: $12.95 (preferred pricing)
Product Code: EA15K50-EA

You may want to also replace the OEM engine oil drain plug with a magnetic plug to capture any suspended or settled particles. Mine didn't come with one. Differential already has one.

[Differential]

I changed out the gear oil in the diff at about 600, 800, 1000, and 1200 miles, then about every 2 or 3 drag strip visits, or about 16-24 passes. HP Supplement says to change it after every competitive event. I take that to mean road course day. I use the listed GM lubricant because I couldn't find anything better that has the same friction modifiers in it. You need those for the eLSD to work properly. A small amount of fine metal filings is normal at the start of your drain but you should not see any flakes or chunks.

I've been getting mine from Amazon. If you'll be doing it yourself, you'll want to get this suction gun too. It doesn't leak and lets you see exactly how much fluid is left.


$17.88 ea.
ACDelco 10-4034 Dexron LS 75W-90 Gear Oil - 32 oz


$22.75 ea.
Plews 30-740 UltraView Suction Gun with Red Tube Ends

[Warning]

Please have them check for chaffing lines on right (passenger) side rear, above differential. I found some on my last safety inspection in December. With such low mileage it may not have rubbed much yet. Definitely want to wrap those lines though. See this post for details: Possible fuel lines rubbing under the car

--Cal

[Tachitup]

Change the brake fluid to Castrol SRF. In comes in a 1 liter container, so buy two. You'll need 1 1/2 to properly flush the system. Don't settle for anything else.

[Stephen12ZL1]

GM states the PF64 oil filter is the choice and if there was a catastrophic failure, I would prefer to have that filter in place. The GM rear diff fluid is the correct fluid to use...not Mobil 1 in the rear diff. Castrol SRF is overkill for most people and incredibly expensive so I recommend Motul 600 as it hasn’t failed me. Use a 5w40 on track that is Dexos 2 certified. Amsoil claims “exceeds Dexos 2 certification” but doesn’t have the GM seal of approval. Mobil 1 15w50 is also acceptable according to the owners manual. Amsoil is great oil and I personally use their Euro spec 5w40 but cannot recommend an oil that doesn’t meet GM’s spec. I have great confidence in their product which sounds contradictory. Many Dexos 2 approved 5w40 products are available from Valvoline, Motul, etc. Good luck and have fun on track!

[Badmojo]

This Dexos licensing reeks of a scam.

http://www.gmdexos.com/owner/brands/

Let's go put some Castrol Edge Turbo Diesel oil in for the track! There are very few "high performance" oils with Dexos 2 certification.

[ninetres]

Dexos is absolutely a licensing scam that has nothing to do with the actually quality of oils that have not paid to be able to use the Dexos stamp

[Stephen12ZL1]

Originally Posted by ninetres

Dexos is absolutely a licensing scam that has nothing to do with the actually quality of oils that have not paid to be able to use the Dexos stamp

“scam” or not, GM requires oil with that standard. They have the power to deny a warranty claim so stick with their protocol.

[RedHot18]

Change the oil and filter, I use Mobil 1 only and the regular weight. Change your brake fluid to a DOT 4 high temp.
When your car is on lift have them check the control arm and sway bar connections, they have had an issue with these coming loose. I put in some special lock washers and blue loc tight. Stock brake pads work well. I'll be doing Sebring on the 27th with Chin to start off 2018, come join the fun, this car rocks on a race track in stock set up. I also have three track days on first set of tires with the stock allignment and tires are still OK for at least one more outing. I'm about 4500 miles total .