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| | | | Joined: Sep 2012 Posts: 222 'Bolter | | 'Bolter Joined: Sep 2012 Posts: 222 | Has anyone had success with using synthetic transmission fluid in a manual transmission? I changed the gear lube in a T18 4 speed to synthetic gear lube and also changed the fluid in my 49 3600 T5 tranny to 50W synthetic gear lube. Both trannies now have shifting problems like the syncros aren't doing there job. I'll put regular gear lube back in the T18 but what Is best for a NWC T5. | | | | | Joined: Sep 2013 Posts: 1,362 'Bolter | | 'Bolter Joined: Sep 2013 Posts: 1,362 | Without fact checking myself, automatic transmission fluid is spected for all T5's. I run ATF in both my T5's one NWC, the other is a WC. No issues.
Good luck,
RonR
Last edited by moparguy; 02/10/2022 4:07 PM.
RonR
1951 3600 with Clark flatbed, T5, 4.10 rear
1970 340 Duster
1990 5.0 V8 Miata (1990 Mustang Gt Drivetrain)
1964 CJ5
| | | | | Joined: Sep 2012 Posts: 222 'Bolter | | 'Bolter Joined: Sep 2012 Posts: 222 | ATF is for world class T5s and 50Weight gear oil is for non world class. Just wondering what others have had success with
Last edited by DaveV; 02/10/2022 2:41 PM.
| | | | | Joined: Oct 2015 Posts: 406 'Bolter | | 'Bolter Joined: Oct 2015 Posts: 406 | ATF in my NWC T5 for the last 20,000 miles or so , no issues .
John
good planning is no substitute for dumb luck
| | | | | Joined: Sep 2011 Posts: 1,456 'Bolter | | 'Bolter Joined: Sep 2011 Posts: 1,456 | synthetic gear lube. Both trannies now have shifting problems like the syncros aren't doing there job. I'll put regular gear lube back in the T18 but what Is best for a NWC T5. Fluid is too slick for syncro to work. G.M. sells manual transmission & transfer case fluid p/n 88861800 which is Dexron II in a new package. Got to be careful, some manuals such as NVG4500 (have one in my 2000 K2500) have a very specific fluid, will damage syncros if not used.
BC
1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc
1949 GMC 250 project in waiting
1960 C60 pasture art
Retired GM dealer tech. 1980 - 2022
| | | | | Joined: Sep 2012 Posts: 222 'Bolter | | 'Bolter Joined: Sep 2012 Posts: 222 | Thanks for the input. I think I'll just use regular ATF | | | | | Joined: Sep 2011 Posts: 1,456 'Bolter | | 'Bolter Joined: Sep 2011 Posts: 1,456 | Try to find Dexron III spec oil, the gm 88861800 fluid or equivalent. Wouldn't advise Dexron VI.
Dex Ii was the o.e. spec for S10 T5.
BC
1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc
1949 GMC 250 project in waiting
1960 C60 pasture art
Retired GM dealer tech. 1980 - 2022
| | | | | Joined: Sep 2012 Posts: 222 'Bolter | | 'Bolter Joined: Sep 2012 Posts: 222 | I did some searching and found a site (History of the Borg-Warner T5) which does recommend Dexron II in the NWC T5. At Advance Auto I found Fram ATF which explains on the back of the bottle that it is a direct replacement for Dexron II and it is nonsynthetic. I'm going that route. | | |
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