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Mon Dec 08, 2008 10:37 pm

I've searched the archives, seen the poll, and read all I could find but I still have a couple questions regarding redline gear oil. I live in the mid-atlantic (NC) and want to drain and fill my '86 Syncro. I know the Bentley procedure and can obtain redline locally. So here goes:
-I've determined MT-90 is highly recommended for the rear vs MTL. It seems like this is debated but MT-90 makes sense to me. Is the redline 75w90NS GL5 what folks use in the front diff or will any old FLAPS GL5 do? Mobil, Valvoline, etc.
-I've read some posts about the "risk" of mixing synthetics with the old dino oil since you can't drain it all out. Is there any truth to this? In a fresh rebuild I can see the value in all fresh synthetic but mixing with dino oil of unknown age? Is it still worth it? Any concerns?
-I read of the horror stories about redline/synthetics and just wondered if I should stick to Dino GL4 which I can also get locally, plus its cheaper.
Thanks in advance.

Tue Dec 09, 2008 10:23 am

I believe you would not put synthetic in a new differential of any make until you had about a 1000 miles on it. Once a differential is broken in, you could switch to synthetic. I would not be concerned about what dino was left, but you could always run it again and change one more time. MTL has a lower pouring viscosity than MT90. Perhaps for the front differential this would be better suited. http://www.redlineoil.com/products_gearlubricants.asp MTL and MT90 or more suited to transaxles.

Tue Dec 09, 2008 5:40 pm

Thanks for the reply rsxsr. I think I read in an older post that you preferred the MTL over MT-90. Still the case?
Doubt I'll do it twice. If a little dino/syn mix is ok I'll run with it.

Tue Dec 09, 2008 10:20 pm

There was a good argument for running the MT90 vs the MTL. We buy MTL by the case for our race cars and customer cars. We even have the local Acura Dealer buying MTL for the cars under warranty with the notchy 2nd gear shift. We don't have a lot of call for the MT90, but next change I may install the MT90. PRI show is this weekend, I'll stop by the Redline booth and see what they recommend for the Vanagon Transaxle and front differential. In our business, the MTL seems to be a reasonable bandaide for worn synchros. We will suggest MTL to a customer when the complaint is notchy shifting when cold and then ok at temp. In these times money is tight for everyone. On a side note, Redline Detergent multigrade synthetic motor oil is now cheaper than what we can buy Mobile One for. Regards

Tue Dec 09, 2008 11:03 pm

I know that Daryl at AAtransaxle.com recommends Redline MT90 for WBX transmissions bolted up to stock engines.

He is a trans rebuilder and frequent contributor to the vanagon.com mailing list.

Check out his website for more info.

Wed Dec 10, 2008 8:43 am

I have an AAtransaxle rebuild with my 2.2 Subaru engine. Daryl recommended MT90 from day one, and I've been very pleased with the performance, especially in cold weather.

Wed Dec 10, 2008 9:27 am

rsxsr wrote: There was a good argument for running the MT90 vs the MTL. We buy MTL by the case for our race cars and customer cars.

rsxr, you'll get about double the gear and R&P life in race cars using LE#9920 over either the Red Line or Mobil one/Delvak gear lubes.
http://www.le-inc.com/index.jsp