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DISCUSSION => Engine + Driveline => Topic started by: Flatsix on June 22, 2007, 02:05:08 PM

Title: Recommended Gearbox Oil
Post by: Flatsix on June 22, 2007, 02:05:08 PM

Just finished the installation of a lightweight flywheel and SACHS sport clutch for my 318is and am now wondering what type of gearbox oil I should use for tranny fill.  Shop manual indicates that I see my dealer.   Dealer recommended Dexron III ATF as does my cheapo Haynes manual.   Any recommendations/other suggestions?  Currently I am eying Castrol Dexron III ATF fluid.   I am also less keen on synthetics as well.  

Note that vehicle is a 91 318is with Gtrag 5-speed gearbox with 130k on drivetrain.  Gearbox shifts smooth and currently does not leak.  

Flatsix

Title: Recommended Gearbox Oil
Post by: m44power on June 22, 2007, 02:31:30 PM

im running BP Dextron III thes it gets hot i have lot of noise then its cold its realy hard to shift DONT USE IT !!! im gone change it very soon....  maybe next time im gone use some motorkote some special product to mix with gearoil

Title: Recommended Gearbox Oil
Post by: nuvolarossa on June 22, 2007, 03:24:16 PM

I need to change it too. I have a little leak, and it's starting to be hard to shift too.

Title: Recommended Gearbox Oil
Post by: ecpreston on June 22, 2007, 04:01:26 PM

Don't know why you're leery of synthetics, but I've personally had a lot of good luck with both Redline MTL and Silkolene Silktran in E30 transmissions. Light enough for street use, heavy enough for the track.

Title: Recommended Gearbox Oil
Post by: Eurospec on June 22, 2007, 05:51:29 PM

This topic has been covered in the past. You'll find the search engine to be very helpful.

Title: Recommended Gearbox Oil
Post by: 318idol on June 22, 2007, 11:23:20 PM

Just use ATF.  Synthestics are a waste, amd at least in my case, the tranny shifts more smoothly with ATF.

Title: Recommended Gearbox Oil
Post by: AL GReeNeRy on June 23, 2007, 03:42:33 AM

i used Redline ATF with D4.  works great.  i grind gears every now and then and it still shifts smoothly regardless

Title: Recommended Gearbox Oil
Post by: AL GReeNeRy on June 23, 2007, 03:43:34 AM

what flywheel did you go with and whered you get the sport clutch upgrade

Title: Recommended Gearbox Oil
Post by: JHZR2 on June 23, 2007, 07:59:24 AM

Quote from: AL GReeNeRy;28323

i used Redline ATF with D4.  works great.  i grind gears every now and then and it still shifts smoothly regardless

That is what I use.  make sure it is the right API spec - gear oil for diffs will leach and attack the soft metals in the synchros, etc., and destroy your gearbox.  Redline D4 has a much better additive package than standard Dex III for extreme pressure/anti-wear, and I would use it with confidence.

Dexron VI is far more shear stable than Dexron III, if you must be anti-syn, which is inherently wrong these days because ATFs now have syn (group III and group IV) components, at least go with Dex IIIH or VI, which are at least semi-synthetic, ad maintain their properties better.

JMH

Title: Response to flywheel inquiry
Post by: Flatsix on June 24, 2007, 08:40:30 PM

Had Jim Rowe at MM machine a 325 flywheel down to 9.5lbs.  Also grooved ring gear.

Title: Response to flywheel inquiry
Post by: Flatsix on June 24, 2007, 08:53:33 PM

Had Jim Rowe at MM machine a 325 flywheel down to 9.5lbs.  Also grooved ring gear.