Normal transmission shifting

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suntennis

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Sep 3, 2020, 12:31:10 PM9/3/20
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My car is a GRX model with the 4 speed overdrive transmission and I question what is a normal speed for smooth down shift from gear 3 to gear 2. On my car this down shift above 25 mph becomes not that smooth. My car has over 50K miles and may have been raced at one time. If a norm for these transmissions is 35 mph for smooth gear change, maybe I am in need of replacing the brass shift rings. Appreciate input on this.

guzz...@gmail.com

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Sep 7, 2020, 8:53:50 AM9/7/20
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Hello Peter here with #78 , I have same transmission and while it isn't the smoothest it isn't near as bad as advertised. On the downshifts are you heel and toeing and double clutching ? I drive the car quite aggressively and find if you use those techniques  ( it takes practice ) it shifts very good . Now I did change pedal positions ( spread them out) which I'll detail if you want but there are a bunch of you tube videos on this technique and it makes driving the car a lot more fun.

suntennis

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Sep 7, 2020, 5:25:42 PM9/7/20
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Thanks for your comment. When down shifting I just shifted without double clutching and revving the engine. Transmissions do have limits, so my question is what is the limit speed for such a transmission with low normal use miles on it?

pet deg

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Sep 7, 2020, 7:33:39 PM9/7/20
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Let me make sure I understand your problem. Are you saying it actually hard to put into the lower gear ( like a bad synchro ) or once you put it into gear and let out clutch the car jerks because engine speed and road speed don't match with the selected gear with the lower RPM ? Was it always like this or did problem just started happening ??

There really isn't a road speed since you could be going from 4th to 3rd or 3rd to 2nd or 4th to 2nd it's really about matching engine speed with the road speed in lower gear.

I assume trans oil level is good , what type of oil are you using in transmission ?


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Subject: [auroracobra] Re: Normal transmission shifting
 
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virdana

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Sep 8, 2020, 5:48:25 PM9/8/20
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Thanks for your input. When trying to down shift from third to second gear above 26 mph or faster it is like the synchro is not doing the job since there would be some grinding of gears. I have only put a few hundred miles on the car since buying it and it has been this way all the time. Checking the oil in the trans is what I failed to do so thanks for the suggestion. When I did try to check the oil level, I discovered  I was unable to remove the fill plug. My next move will be to have a mechanic remove the plug. There is red stuff on the threads of the plug which I hope is not red locktite. Regardless what it is, someone else will have to get the plug out.  I have no idea what oil is in the trans.

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pet deg

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Sep 8, 2020, 11:09:33 PM9/8/20
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Well it's always good to check and actually renew all fluids in a new to you but used car.  Why don't you try double clutching ? I dove an Alfa for 25 years as a daily driver with bad 2nd gear synco and it really didn't bother me or restrict fun of driving car at all. 

But the big thing is if it goes into gear on downshifts or upshifts better with double clutching it will tell you the Syncros are the problem. All double clutching is a double pump of clutch pedal . nothing to it .

here's one video but there are a bunch ( maybe better ) on you tube

In this video, I show you how to double clutch in a manual car. I’m using my Honda Accord Coupe for the video with a 5 speed manual transmission. It the same process for any manual car. Double clutching is a method of shifting gears used primarily for vehicles with an unsynchronized manual transmission, such as commercial trucks and specialty ...



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Sent: Tuesday, September 8, 2020 5:48 PM
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virdana

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Sep 9, 2020, 12:04:20 AM9/9/20
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Thanks again for sound good advice. You are right, the car is to be used and enjoyed which I do. The down shift question was to find out only if my transmission shifts like new or if it is showing signs of wear.
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