GOOG Posted August 11, 2018 Share Posted August 11, 2018 Does switching to synthetic gear lube make a noticeable difference in the shifting of a transmission? I don't like the way my Mack 18 speed shifts and have heard switching to synthetic will help. Quote Link to comment Share on other sites More sharing options...
Ezrider Posted August 11, 2018 Share Posted August 11, 2018 i would be surprised if it made any difference in how it shifts. but synthetic in your trans is always a good idea. Quote Link to comment Share on other sites More sharing options...
kscarbel2 Posted August 11, 2018 Share Posted August 11, 2018 Synthetic won't grow metal back, but it is extremely good lubricant. Mack TO-A Plus approved oils for manual transmissions including your T2180, both conventional and synthetic, are listed on page 19 (link below). https://www.macktrucks.com/-/media/files/pv776-89149448.pdf?la=en I'd probably choose Amsoil, which I see meets the Mack spec. https://www.amsoil.com/lit/databulletins/g2902.pdf https://www.amsoil.com/shop/by-product/transmission-fluid/manual/sae-50-long-life-synthetic-transmission-oil/ Then again, using Mack Bulldog Syn Trans Lube is another strategy. Quote Link to comment Share on other sites More sharing options...
1965 Posted August 11, 2018 Share Posted August 11, 2018 It always seems to help (probably my imagination) just when changing the lube with regular lube; in the intervals. If your comparing the shift with an Eaton trans.; it’s not ever going to happen. I’ve had 2 - T318LR’s & I really liked them but they don’t shift as easy as an Eaton. (My opinion). 1 Quote Link to comment Share on other sites More sharing options...
GOOG Posted August 12, 2018 Author Share Posted August 12, 2018 Thanks for all your input. Quote Link to comment Share on other sites More sharing options...
1965 Posted August 12, 2018 Share Posted August 12, 2018 I bought my 12 model from a Mack dealer; had oil analyze ran on the entire truck. The transmission should needing replacing. The manual said either 50w or 80-90w. According to temperature. Everybody on here said 80-90w & that’s what I told salesman I wanted. Anyway I ran it trusting the guy, I changed it because I thought it might need flushing again because of leaking pto housing that I fixed. I put 80-90w in it & it quieted it down a bunch. I’m in hot atmosphere. I know what I drained wasn’t 80-90w. Quote Link to comment Share on other sites More sharing options...
Ezrider Posted August 12, 2018 Share Posted August 12, 2018 the 50w and 80-90 use two different viscosity rating systems i forget witch is with but one is i think api and the other sae the viscosity is closer between the two than it would seem. Quote Link to comment Share on other sites More sharing options...
Popular Post Mack Technician Posted August 12, 2018 Popular Post Share Posted August 12, 2018 (edited) Go synthetic in cold regions. The benefits outweigh the cost in fuel mileage and component protection. On a cold morning the trans and diffs are so stiff you can just push in the clutch and stop rolling as though hitting the brakes(w/80w-90). You have to feed the gear boxes extra fuel to get them hot, poor efficiency. Park at the truck stop for an hour, diff temps drop and your right back where you started. At temps below -0- you will likely damage your synchro. When you run non synthetic you will clash the slider clutch of the synchro on your first shift. The gear lube is too thick and won’t squeeze out of the plates to allow synchronclutches to work. Synthetic doesn’t swing viscosity like EP so you don’t get clash. If you do still use non synthetic just cycle your synchro a few times before you move and you may be OK. In warm regions use what you like. Edited August 12, 2018 by Mack Technician 3 Quote Link to comment Share on other sites More sharing options...
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