Technical Slight grinding/buzzing while selecting 3rd gear

[DjPatD]

there is a slight grind whenever i go from 2nd to 3rd gear. it seems to stop only when im in 2nd gear and im ready to shift up, and i slightly accelerate while the clutch pedal is pressed then i shift to the 3rd.

if i were to normally shift to 3rd it would work but it would definitely grind.
does this mean that 3rd gear would need to be rebuilt?

thanks guys

 

[TeamTowleMotorsports]

Could be your shift synchros going bad. I had that problem before and changed out the synchros and it was fine.

 

[DjPatD]

yea im having a problem with the first three gears, im just gonna have to change out first, second and third.

thanks for your help

 

[MistyX19]

I have trouble finding 3rd gear sometimes on my Gran Finaly. Do you have to be a certain speed or at a certain rev to get it into the gear nice and slick, instead of hear a slight crunch every now and then I wonder?

 

[Lucio]

Before you replace anything try changing the oil and refill with Redline MTL. Expensive stuff but worth every penny. I know you are thinking that an oil cannot remedy your problem but believe me the stuff is magic. (Was recommended by Jimbro a while back) Give it a go.

 

[DjPatD]

MISTY, i have tried everything, slower speeds from second gear to the third, high revving in second to about 4500rpm then to 3rd, normal 3k rpm shifting then slightly accelerating while the clutch is depressed etc etc and it still grinds slightly.

im assuming it has to be a bad synchro. i have a bad 2nd gear synchro as well so now im driving 2nd - 4th - 5th only LOL.

its sad but it works

Lucio - I actually am using redline, it was recommended from my mechanic from italy, stuff works miracles!

 

[digger58]

Double clutch both on the way up and down, if no grinding then syncro rings need replacing, i.e. clutch to take out of gear, release when in neutral, then clutch again to engage gear, this in effect syncronises the gear train to enable a smooth shift. If you ever drove old trucks and tractors this was common practice. Hope this helps, T

 

[StorminNormin]

Double clutch both on the way up and down, if no grinding then syncro rings need replacing, i.e. clutch to take out of gear, release when in neutral, then clutch again to engage gear, this in effect syncronises the gear train to enable a smooth shift. If you ever drove old trucks and tractors this was common practice. Hope this helps, T

I also have the same problem with 3rd gear and double de-clutching works. Looks like I'll be replacing the syncro rings at some point.

 

[jimbro1000]

If the synchro is failing (and it sounds like it is) then it is best to get the job done sooner rather than later. The accumulating of metal fragments in the oil can start to cause problems and if the ring goes with a bang it can take other gears out with it when it goes. I've just had to do a partial rebuild on a box where debris in the oil forced the differential gears to mislocate and ultimately crack the gearbox housing and this was supposed to be a factory reconditioned gearbox. Equally so I've had an X1/9 where the gearbox did the same while I was driving it, ironically on the way home from having the 3rd gear synchros replaced - you can imagine how angry I was about that, aggravated by the workshop closing 5 minutes earlier and leaving me stranded and receiving lots of verbal abuse from other road users who discovered the 3 litre puddle of fresh gear oil in the middle of the road.

 

[DjPatD]

If the synchro is failing (and it sounds like it is) then it is best to get the job done sooner rather than later. The accumulating of metal fragments in the oil can start to cause problems and if the ring goes with a bang it can take other gears out with it when it goes. I've just had to do a partial rebuild on a box where debris in the oil forced the differential gears to mislocate and ultimately crack the gearbox housing and this was supposed to be a factory reconditioned gearbox. Equally so I've had an X1/9 where the gearbox did the same while I was driving it, ironically on the way home from having the 3rd gear synchros replaced - you can imagine how angry I was about that, aggravated by the workshop closing 5 minutes earlier and leaving me stranded and receiving lots of verbal abuse from other road users who discovered the 3 litre puddle of fresh gear oil in the middle of the road.

JIMBRO, I'm currently avoiding 3rd gear entirely to stop the grinding issue. However coincidently i have found out this morning that accelerating to 4500rmp exactly into 2nd gear then depressing the clutch and accelerating slightly before shifting into third makes no noise at all!
- i still believe that it is a synchro problem and that this just coincidently happens to be the perfect shift point of the 3rd gear or the exact "sweet spot" as to where no grinding would occur.

- as to the tranny, midwest x1/9 doesn't completely have all the parts to rebuilt the entire tranny nor does it have all synchros for all gears.
im currently searching on ebay or other places where i can find a completely rebuilt or new 5speed tranny. there is a 4speed completely rebuilt on ebay right now for a low price of 300. USD i believe, however its a 4 speed:yuck:

 

[MistyX19]

MISTY, i have tried everything, slower speeds from second gear to the third, high revving in second to about 4500rpm then to 3rd, normal 3k rpm shifting then slightly accelerating while the clutch is depressed etc etc and it still grinds slightly.

im assuming it has to be a bad synchro. i have a bad 2nd gear synchro as well so now im driving 2nd - 4th - 5th only LOL.

its sad but it works

Thanks for the info on this, I will try it and see. If I have to change the synchro, how easy is it to do and is it expensive?

Drive Safe
Misty.

 

[DjPatD]

Thanks for the info on this, I will try it and see. If I have to change the synchro, how easy is it to do and is it expensive?

Drive Safe
Misty.

- sure no problem, i found out this morning actually, try revving up to 4,500rpm's while driving in 2nd gear then depress the clutch, accelerate slightly probably to 5,000rpms or so, and then shift to 3rd gear. even with the bad synchro it shifts perfectly smooth. This is probably the ideal 3rd gear shift.

 

[jimbro1000]

In the UK I believe Eurosport would be the safest bet for gearboxes or parts.

If you were up to the job I seem to remember that the differences between the 4-speed and 5-speed boxes do not include the 3rd gear components so it should be possible to salvage the necessary parts, failing all else it is of course possible to get a pair of synchros made to your (or original) specification. I had to do this on my race car to replace a pair of gears from Colotti only to discover (having sent the damaged parts to Italy) that Colotti didn't make the gears I started with - they turned off a pair of gears for me and had them delivered inside of a week, it wasn't cheap but then race spec components never are...

 

[erich]

I seem to remember that the differences between the 4-speed and 5-speed boxes do not include the 3rd gear components so it should be possible to salvage the necessary parts,.

Careful - there are two kinds of four-speed 3rd gear setups. The early one, through to mid-78 used a 65mm syncro ring on 3rd and 4th gear. Mid-78 4-speeds and all 5-speeds used 78mm rings, with appropriate changes to the gears, slider, and hub. The early four-speed bits are NOT compatible with the five-speed.