Rearend Fluid - Synthetic or not?

Ben Kallies · 07-17-2007, 07:25 PM

I have been given conflicting advice on what type of diff fluid to use. I have a Moser 12 bolt with high-impact race gears and spool in a '71 Corvette Stocker with stick. The gentleman that I spoke with at Moser said that it doesn't matter as long as it's 80w90 weight. An independent differential shop advised me not to use synthetic because it doesn't protect as well with regards to the intitial hit on launch. Still others have told me that is a bunch of bologna and synthetic is the way to go. Anyone willing to share their experience? Thank you in advance for your time. Ben Kallies 3869

Arnold Greene · 07-17-2007, 07:35 PM

For the best life in a stick shift 12 bolt, run 2 quarts of 80w-140 synthetic with approximately 2 ounces of moly mixed in. You will be surprised how well this works and it will not slow the car down.

Woodro Josey · 07-17-2007, 08:51 PM

I'd have to go on Arnolds reccomendation,as he has had a lot of dogs in this hunt!

Oldtimer · 07-17-2007, 09:22 PM

Hay Ben, Sounds like you got your done ! Go with what Arnold said, he and Woodro have been around as long as I have, I dont know if thats good or not. Send me some pix. Regards, bob pagano L88BOB@aol.com

Ben Kallies · 07-18-2007, 07:34 AM

Thank you guys. Arnold, is there any particular brand of fluid that you recommend?

Mike Pearson · 07-18-2007, 08:17 AM

I have had great results with valvoline full synthetic. Its cheap and available at most parts stores. I have a dana in my super stock H/A camaro and usually get about 8 - 10 seasons on a gear set. The gears last alot longer with the synthetic lube.

Mike

Arnold Greene · 07-18-2007, 10:03 AM

Ben, I've used Mobil 1, Red Line, Royal Purple, Castrol Syntec, and Valvoline. I use whatever is available. Right now, I am using RP, but the weight is more important than the brand, IMHO. Don't forget the moly and make sure the rear is warm to keep it in suspension, before you make a hit. Good luck.

John Kelley · 07-18-2007, 10:20 AM

Where do you get the "moly"and does it have a brand name ?

Ben Kallies · 07-18-2007, 11:05 AM

Can I assume that it is OK to break it in with the synthetic as well? Thanks for the help. - Ben Kallies 3869

Arnold Greene · 07-18-2007, 11:19 AM

Yes, it is fine for break in. The last moly that I bought was under the name, Mr. Moly. Most parts stores carry it, but it only comes in quarts, that I have found. I think I paid $28 for the last quart I bought. Also helps in the Jerico.

You will most likely have to reset your backlash after your first race. The Pro gears have a tendency to bend the teeth on the ring gear, and then stabilize.

07-17-2007, 07:25 PM	#1
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 107 Likes: 2 Liked 0 Times in 0 Posts	Rearend Fluid - Synthetic or not? I have been given conflicting advice on what type of diff fluid to use. I have a Moser 12 bolt with high-impact race gears and spool in a '71 Corvette Stocker with stick. The gentleman that I spoke with at Moser said that it doesn't matter as long as it's 80w90 weight. An independent differential shop advised me not to use synthetic because it doesn't protect as well with regards to the intitial hit on launch. Still others have told me that is a bunch of bologna and synthetic is the way to go. Anyone willing to share their experience? Thank you in advance for your time. Ben Kallies 3869

07-17-2007, 07:35 PM	#2
Arnold Greene Member Join Date: Mar 2003 Posts: 135 Likes: 0 Liked 3 Times in 2 Posts	Re: Rearend Fluid - Synthetic or not? For the best life in a stick shift 12 bolt, run 2 quarts of 80w-140 synthetic with approximately 2 ounces of moly mixed in. You will be surprised how well this works and it will not slow the car down. __________________ Arnold Greene IHRA/NHRA 2420 A/S, B/S

07-17-2007, 08:51 PM	#3
Woodro Josey Senior Member Join Date: Jul 2007 Posts: 805 Likes: 0 Liked 3 Times in 1 Post	Re: Rearend Fluid - Synthetic or not? I'd have to go on Arnolds reccomendation,as he has had a lot of dogs in this hunt! __________________ Woodro Josey 2002 STK

07-17-2007, 09:22 PM	#4
Oldtimer Junior Member Join Date: Jul 2002 Location: Arkansas Posts: 87 Likes: 0 Liked 0 Times in 0 Posts	Re: Rearend Fluid - Synthetic or not? Hay Ben, Sounds like you got your done ! Go with what Arnold said, he and Woodro have been around as long as I have, I dont know if thats good or not. Send me some pix. Regards, bob pagano L88BOB@aol.com __________________ Bob Pagano L88BOB@aol.com www.dyainc.org 4033 AA/SA

07-18-2007, 07:34 AM	#5
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 107 Likes: 2 Liked 0 Times in 0 Posts	Re: Rearend Fluid - Synthetic or not? Thank you guys. Arnold, is there any particular brand of fluid that you recommend?

07-18-2007, 08:17 AM	#6
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,443 Likes: 613 Liked 1,916 Times in 574 Posts	Re: Rearend Fluid - Synthetic or not? I have had great results with valvoline full synthetic. Its cheap and available at most parts stores. I have a dana in my super stock H/A camaro and usually get about 8 - 10 seasons on a gear set. The gears last alot longer with the synthetic lube. Mike __________________ Mike Pearson 2485 SS

07-18-2007, 10:03 AM	#7
Arnold Greene Member Join Date: Mar 2003 Posts: 135 Likes: 0 Liked 3 Times in 2 Posts	Re: Rearend Fluid - Synthetic or not? Ben, I've used Mobil 1, Red Line, Royal Purple, Castrol Syntec, and Valvoline. I use whatever is available. Right now, I am using RP, but the weight is more important than the brand, IMHO. Don't forget the moly and make sure the rear is warm to keep it in suspension, before you make a hit. Good luck. __________________ Arnold Greene IHRA/NHRA 2420 A/S, B/S

07-18-2007, 10:20 AM	#8
John Kelley Senior Member Join Date: Feb 2002 Location: Tightwad,TEXAS Posts: 911 Likes: 6 Liked 3 Times in 3 Posts	Re: Rearend Fluid - Synthetic or not? Where do you get the "moly"and does it have a brand name ?

07-18-2007, 11:05 AM	#9
Ben Kallies Member Join Date: Jan 2005 Location: Milwaukee, WI Posts: 107 Likes: 2 Liked 0 Times in 0 Posts	Re: Rearend Fluid - Synthetic or not? Can I assume that it is OK to break it in with the synthetic as well? Thanks for the help. - Ben Kallies 3869

07-18-2007, 11:19 AM	#10
Arnold Greene Member Join Date: Mar 2003 Posts: 135 Likes: 0 Liked 3 Times in 2 Posts	Re: Rearend Fluid - Synthetic or not? Yes, it is fine for break in. The last moly that I bought was under the name, Mr. Moly. Most parts stores carry it, but it only comes in quarts, that I have found. I think I paid $28 for the last quart I bought. Also helps in the Jerico. You will most likely have to reset your backlash after your first race. The Pro gears have a tendency to bend the teeth on the ring gear, and then stabilize. __________________ Arnold Greene IHRA/NHRA 2420 A/S, B/S