baa325 Posted November 30, 2022 Report Share Posted November 30, 2022 My team is running an NB Miata. We have experienced transmission failures on a regular basis over the past 3 years. Typically we get between 80 and 100 hours. Is this typical? We buy rebuilt transmissions from Jim Drago in Memphis. Some have speculated that the trans oil temperature is too high. What temperature should the oil typically be? We plan to install a temperature probe in the next one. Other suggestions include air ducting to the trans. We use Amsoil Manual trans oil. We change the oil every 40 hours. Finally is our problem just one of driver abuse? Quote Link to comment Share on other sites More sharing options...
wvumtnbkr Posted December 1, 2022 Report Share Posted December 1, 2022 What's the failure mode? We had synchro crunching after a race or 2 in our rx7. I talked with mazdatrix and they recommended idemitsu gear oil for the Trans. After that, never had another issue. The rx7 and miata gearboxes are almost identical, so I'd say it's worth a shot! Quote Link to comment Share on other sites More sharing options...
ETR Posted December 1, 2022 Report Share Posted December 1, 2022 I recently switched to idemitsu based on wvumtnbkr’s recommendation and I think I like it. Really seems like good stuff, especially on a hot day. At champcar power levels don’t worry about temperatures, just -Run good fluid -Talk to your drivers about smooth, positive shifting <—-probably 95% of the issue -Rev match, especially on a 4/3 shift -Make sure clutch is adjusted properly for full throw Our first couple years I think we were also on pace for 80-100hrs per box, we get a bit more these days. Most notably though, we haven’t had sudden transmission failures at the track since I began preaching smoother shifting. Knock on wood… Quote Link to comment Share on other sites More sharing options...
MMiskoe Posted December 1, 2022 Report Share Posted December 1, 2022 We switched to synthetic ATF a long time ago and we preach for slow deliberate shifts and rev matching. Had a renter once brag about how fast he could shift and by the end of the day third gear was pretty crunchy. The fluid gets changed before every weekend. Quote Link to comment Share on other sites More sharing options...
tommytipover Posted December 1, 2022 Report Share Posted December 1, 2022 I am amazed at how fast some people shift. There are some real animals out there. I was taught as a teenager to use a light touch on the shifter with an almost imperceptible pause between gears. It never occurred to me to try and speed that up to improve lap time. I am pretty slow, but I pay for my own transmissions too. 1 Quote Link to comment Share on other sites More sharing options...
WastedAccounts Posted December 1, 2022 Report Share Posted December 1, 2022 I had a teammate leave the team and suddenly stopped having transmission issues. 4 7 Quote Link to comment Share on other sites More sharing options...
LuckyKid Posted December 1, 2022 Report Share Posted December 1, 2022 We run used transmissions and don't have systemic issues. Lowering the car too much which cut off airflow smoked one. The exhaust can also overheat them as well. 1-second shifts should help keep them going longer. Quote Link to comment Share on other sites More sharing options...
takjak2 Posted December 2, 2022 Report Share Posted December 2, 2022 Just here to confirm all of the above. Not surprised to hear of crunchy gears at 100 hours. We're also not complaining when we get 100 hours out of anything. 1 Quote Link to comment Share on other sites More sharing options...
Special K Posted December 7, 2022 Report Share Posted December 7, 2022 We've run the same transmission since 2019. Just change the fluid (redline) before every race and its been fine. We recently swapped to idemitsu but haven't raced with it yet Quote Link to comment Share on other sites More sharing options...
55mini Posted December 29, 2022 Report Share Posted December 29, 2022 (edited) Since we started in 2015 we have had three failures between two cars. One the shifting tower broke and a second was my fault after a rebuild I didn't lock the enddent bolts in place and they backed out. When it goes in two gears at once bad things happen. The third just got tired. All where used parts car trans and we use Redline in all of them. The key to any of this is driver, slam shifts and not working clutch properly. Edited December 30, 2022 by 55mini spacing Quote Link to comment Share on other sites More sharing options...
gundy Posted December 29, 2022 Report Share Posted December 29, 2022 4 hours ago, 55mini said: The key to any of this is driver, slam shifts and not working clutch properly. It took us a while (4 transmissions in 2 years) but we learned the same thing. Quote Link to comment Share on other sites More sharing options...
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