'03 with Gear Grinding
05-14-2003, 05:28 AM
#11
Registered User
some advice for your problem.
-I also had the occasional high-rev 1-2 grind, but changing the tranny fluid out to Redline MT-90 recently has greatly helped. Most of the notchiness in other gears is gone as well. My car had 7k when I changed it out.
-read this post when you have 20 minutes or so.
-a lot of members have the same problem that you are describing, and as mentioned, there is a tsb on the issue. If it is persistent after the fluid swap, use your warranty and get it fixed.
-a few other things that may help to avoid the grind:
*make sure that your clutch is adjusted properly, and that it is to the floor when you shift
*others, myself included, tend to pull the shifter towards the left side of the gearbox when shifting into 2nd
*a very small pause (detailed in the above link) will help the tranny's syncros accept the shift smoother.
Rob
-I also had the occasional high-rev 1-2 grind, but changing the tranny fluid out to Redline MT-90 recently has greatly helped. Most of the notchiness in other gears is gone as well. My car had 7k when I changed it out.
-read this post when you have 20 minutes or so.
-a lot of members have the same problem that you are describing, and as mentioned, there is a tsb on the issue. If it is persistent after the fluid swap, use your warranty and get it fixed.
-a few other things that may help to avoid the grind:
*make sure that your clutch is adjusted properly, and that it is to the floor when you shift
*others, myself included, tend to pull the shifter towards the left side of the gearbox when shifting into 2nd
*a very small pause (detailed in the above link) will help the tranny's syncros accept the shift smoother.
Rob
05-14-2003, 05:29 AM
#12
[QUOTE]Originally posted by Sheister
[B]... So, I'm thinking that the grind in my car is probably related to the transmission warming up, how dirty the transmission gear oil is, and how fast I shift.
[B]... So, I'm thinking that the grind in my car is probably related to the transmission warming up, how dirty the transmission gear oil is, and how fast I shift.
05-14-2003, 09:05 AM
#14
Registered User
Thread Starter
Join Date: Aug 2002
Location: San Francisco, CA
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
Thaks all for replies.
I guess I can either: 1. Let the dealership do the TSB. (I'm worrying about the mechanic doing a good job)
2. Try to replace tranny fluid Then to see if grinding dissapear.
On my way to work this morning, I couldn't duplicate grinding. I wonder I should just live with it for now.
I guess I can either: 1. Let the dealership do the TSB. (I'm worrying about the mechanic doing a good job)
2. Try to replace tranny fluid Then to see if grinding dissapear.
On my way to work this morning, I couldn't duplicate grinding. I wonder I should just live with it for now.
05-14-2003, 10:23 AM
#16
Registered User
Thread Starter
Join Date: Aug 2002
Location: San Francisco, CA
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by gernby
.....but with frequent oil changes, and more consious shifting, I have reduced it to about 1 every 1000-1500 miles.
.....but with frequent oil changes, and more consious shifting, I have reduced it to about 1 every 1000-1500 miles.
05-14-2003, 10:27 AM
#17
Administrator
You need to know how syncromesh works. The syncros are an idiots rev matching device. When you come out of gear and into another the shafts must slow down (upshift) or speed up (downshift) so the gears can match up.
The syncros are brass rings that when squeezed together cause friction and thus acheive the speed match. This happens when you shift. If you shift too fast you don't give the syncros enough time to do their thing and you mash the gears together (grind) before they are speed matched.
The reason that this happens between 1st and 2nd is that that's where the greatest difference is in gear ratios. It's a big leap from 1 to 2. The other gears don't have this problem because they are closer in terms of ratio.
The only thing you can do is not force the 1-2 shift. Apply pressure to the shifter and wait for the syncros to get their job done. It will add .5 s to your 1-2 shift but you won't grind. There is simply no other solution to this other than to change the gear ratios so they are a closer match.
1st gear is always a compromise. On the one hand you want the ratio high enough that you don't stall the car and on the other you want it to be as closely matched to 2nd gear as possible so you don't grind gears. The only real solution is to change the ratio of 1st gear which will make the car nearly undrivable in traffic.
The TSB was for syncros that were out of spec and thus didn't work correctly. People with out of spec syncros would grind gears more than they should, even on reasonably slow and smooth 1-2 shifts. It wasn't designed to overcome the ratio mismatch and solve all gear grinds on agressive shifts from 1-2.
The 1st gear issue is a problem for drag racers and autox'ers who actually use 1st gear. The only solution for them is to lower the 1st gear ratio so it more closely matches 2nd gear's ratio.
The descriptions I've offered are pretty general but the logic is sound. Please don't nitpick, I don't have time to write an essay.
1st: 3.133
2nd: 2.045 (delta 1.088)
3rd: 1.481 (delta 0.564)
4th: 1.161 (delta 0.320)
5th: 0.970 (delta 0.191)
6th: 0.810 (delta 0.160)
Notice the ratio of 1st is almost 50% higher than 2nd while 2nd is only 25% higher than 3rd and so on. If you lowered the delta of 1st-2nd to say 0.800 you'd almost never grind but you'd have to really baby the clutch getting rolling in 1st.
HTH
The syncros are brass rings that when squeezed together cause friction and thus acheive the speed match. This happens when you shift. If you shift too fast you don't give the syncros enough time to do their thing and you mash the gears together (grind) before they are speed matched.
The reason that this happens between 1st and 2nd is that that's where the greatest difference is in gear ratios. It's a big leap from 1 to 2. The other gears don't have this problem because they are closer in terms of ratio.
The only thing you can do is not force the 1-2 shift. Apply pressure to the shifter and wait for the syncros to get their job done. It will add .5 s to your 1-2 shift but you won't grind. There is simply no other solution to this other than to change the gear ratios so they are a closer match.
1st gear is always a compromise. On the one hand you want the ratio high enough that you don't stall the car and on the other you want it to be as closely matched to 2nd gear as possible so you don't grind gears. The only real solution is to change the ratio of 1st gear which will make the car nearly undrivable in traffic.
The TSB was for syncros that were out of spec and thus didn't work correctly. People with out of spec syncros would grind gears more than they should, even on reasonably slow and smooth 1-2 shifts. It wasn't designed to overcome the ratio mismatch and solve all gear grinds on agressive shifts from 1-2.
The 1st gear issue is a problem for drag racers and autox'ers who actually use 1st gear. The only solution for them is to lower the 1st gear ratio so it more closely matches 2nd gear's ratio.
The descriptions I've offered are pretty general but the logic is sound. Please don't nitpick, I don't have time to write an essay.
1st: 3.133
2nd: 2.045 (delta 1.088)
3rd: 1.481 (delta 0.564)
4th: 1.161 (delta 0.320)
5th: 0.970 (delta 0.191)
6th: 0.810 (delta 0.160)
Notice the ratio of 1st is almost 50% higher than 2nd while 2nd is only 25% higher than 3rd and so on. If you lowered the delta of 1st-2nd to say 0.800 you'd almost never grind but you'd have to really baby the clutch getting rolling in 1st.
HTH
05-14-2003, 11:13 AM
#18
Registered User
Join Date: Oct 2002
Posts: 4,349
Likes: 0
Received 0 Likes
on
0 Posts
[QUOTE]Originally posted by cthree
[B]You need to know how syncromesh works. The syncros are an idiots rev matching device. When you come out of gear and into another the shafts must slow down (upshift) or speed up (downshift) so the gears can match up.
The syncros are brass rings that when squeezed together cause friction and thus acheive the speed match. This happens when you shift. If you shift too fast you don't give the syncros enough time to do their thing and you mash the gears together (grind) before they are speed matched.
The reason that this happens between 1st and 2nd is that that's where the greatest difference is in gear ratios. It's a big leap from 1 to 2. The other gears don't have this problem because they are closer in terms of ratio.
The only thing you can do is not force the 1-2 shift. Apply pressure to the shifter and wait for the syncros to get their job done. It will add .5 s to your 1-2 shift but you won't grind. There is simply no other solution to this other than to change the gear ratios so they are a closer match.
[B]You need to know how syncromesh works. The syncros are an idiots rev matching device. When you come out of gear and into another the shafts must slow down (upshift) or speed up (downshift) so the gears can match up.
The syncros are brass rings that when squeezed together cause friction and thus acheive the speed match. This happens when you shift. If you shift too fast you don't give the syncros enough time to do their thing and you mash the gears together (grind) before they are speed matched.
The reason that this happens between 1st and 2nd is that that's where the greatest difference is in gear ratios. It's a big leap from 1 to 2. The other gears don't have this problem because they are closer in terms of ratio.
The only thing you can do is not force the 1-2 shift. Apply pressure to the shifter and wait for the syncros to get their job done. It will add .5 s to your 1-2 shift but you won't grind. There is simply no other solution to this other than to change the gear ratios so they are a closer match.
05-14-2003, 05:03 PM
#20
Originally posted by swtazn97
i read some guy mixed 1/2 Redline MTL and 1/2 Redline MT-90, said it helped eliminate his 1st - 2nd gear grind by a lot.
i read some guy mixed 1/2 Redline MTL and 1/2 Redline MT-90, said it helped eliminate his 1st - 2nd gear grind by a lot.