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'72 Opel GT (Sara)
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2,119 Posts
Too much gear oil?

Is it possible to overfill the transmission with oil and have that affect shifting? I just replaced the O-ring and cup seal on my speedometer drive which eliminated a slow drip there and in the process decided it would be prudent to top off the fluid level. I followed the method described of pumping 90W gear oil in there (Coastal brand) until it came pouring out and then quickly replaced the plug (so I assume the tranny is full to the gills in oil). The reason I ask about overfilling is that now shifting into first gear is tough at first. It requires a good bit of force and a double "click" can be felt as it goes into gear. Eventually, with driving, the resistance lessens until finally it becomes rather easy. Note that none of the other gears exhibit this behavior whether up-shifting or down-shifting. I assume shifting into first gets easier as the fluid warms up (and it is getting colder out even here in Atlanta). So, I am wondering if I should drain some that gear oil back out?

Thanks,

Matt
 

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'72 Opel GT (Sara)
Joined
·
2,119 Posts
newman try a different brand or weight. I run 80/90 in all my manual trans cars with the exception of my Subaru due to having a rather expensive center diff inside. I always use Castrol brand in daily drivers. HTH
It will shift better with a GL-4 lube in it. The brass parts inside the transmission will last longer too. It takes some effort to find GL-4 80-90 sometimes, but it is out there. All older transmisions work better with something other than GL-5

Tom
Thanks for the suggestions! Shifting was easier this morning but then again the temps are rising back up here in Atlanta so that probably explains it...

Matt
 
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