Clutch or Synchronizer Issue ?

[Little Mt. Fuji]

I was in a similar state of mind when i first bought my used 13 MT @ 69k miles. I just changed the fluids just so I know what is in there and how long its been in there. Fresh fluids definitely helped make shifts more consistent and I haven't been locked out of 1st since.

[ermax]

Originally Posted by Drakiv

So when I had my transmission rebuilt with my gear set, they timed the synchros and I never have the problem I used to with stock. So I wonder if someone gets their synchros timed on a stock set if it would remove the problem or not.

If someone charged you money to "time" your syncros, go back to them now and demand a refund because their is no such thing. Hahaha

[ermax]

I would say change your fluid to one that does better when cold but seeing where you are located I don't think cold is your problem, especially not this time of the year. I'm in Florida and year round mine slips right into gear. A common complaint on the IS300 tranny is cold shifting. I changed my IS300 to Honda MTF and it solved my cold shifting problems. But the FRS has been fine even on the OEM fluid.

I would verify that the clutch is fully disengaging. Jack the rear wheels off the ground, start the car, hold the clutch to the floor for 10secs to be sure the output shaft has fully spun down and then while still holding the clutch, put it in 1st. Have someone else watching the rear wheels to make sure they don't start turning when you put it in second. Remember, you are wanting to do this with the clutch to the floor. Obviously the wheels will turn if you're in gear with the clutch out. You can also do this test with the car on the ground but the clutch has to be really messed up to move the mass of the entire car while the clutch is pressed. So to be absolutely sure it's best to do it with the rears off the ground. The slightest drag will make shifting difficult.

[Drakiv]

Originally Posted by ermax

If someone charged you money to "time" your syncros, go back to them now and demand a refund because their is no such thing. Hahaha

They didn't charge me anything for it, it was part of their service. And I misspoke, it was synchro blueprinting, you can go talk to Jacks Transmissions @JacksTrans about it if you want.

https://www.jackstransmissions.com/p...o-blueprinting

[B.RUDY.Z]

Originally Posted by Drakiv

So when I had my transmission rebuilt with my gear set, they timed the synchros and I never have the problem I used to with stock. So I wonder if someone gets their synchros timed on a stock set if it would remove the problem or not.

how much did that cost? if this truly helped then i want to consider getting it done

[Drakiv]

well its whatever they charge for their service, I have no idea. You would have to call them. I had it done when they installed my PAR gearset, so what they charged me would be different than what they charge you.

[Wpomp]

Originally Posted by ermax

I would say change your fluid to one that does better when cold but seeing where you are located I don't think cold is your problem, especially not this time of the year. I'm in Florida and year round mine slips right into gear. A common complaint on the IS300 tranny is cold shifting. I changed my IS300 to Honda MTF and it solved my cold shifting problems. But the FRS has been fine even on the OEM fluid.

I would verify that the clutch is fully disengaging. Jack the rear wheels off the ground, start the car, hold the clutch to the floor for 10secs to be sure the output shaft has fully spun down and then while still holding the clutch, put it in 1st. Have someone else watching the rear wheels to make sure they don't start turning when you put it in second. Remember, you are wanting to do this with the clutch to the floor. Obviously the wheels will turn if you're in gear with the clutch out. You can also do this test with the car on the ground but the clutch has to be really messed up to move the mass of the entire car while the clutch is pressed. So to be absolutely sure it's best to do it with the rears off the ground. The slightest drag will make shifting difficult.

I am having a similar issue to the OP, have changed fluid to Motul 300, but and becoming more convinced I may have some clutch drag. Can this also cause the shifter to get stuck in gear? Every few days my shifter will get stuck in either reverse or first, and will require a great deal of force to get it back to neutral. It also feels much notchier than normal to shift through gears.

After confirming by putting the rear wheels up in the air, how is a clutch drag issue resolved?

Thanks.

[ermax]

Originally Posted by Wpomp

I am having a similar issue to the OP, have changed fluid to Motul 300, but and becoming more convinced I may have some clutch drag. Can this also cause the shifter to get stuck in gear? Every few days my shifter will get stuck in either reverse or first, and will require a great deal of force to get it back to neutral. It also feels much notchier than normal to shift through gears.



After confirming by putting the rear wheels up in the air, how is a clutch drag issue resolved?



Thanks.

Yes clutch drag would make it hard to pull out of gear because it would put a little load on the gears. Clutch drag can be caused by a bunch of things. Most common would be air in the line due to a bad master or slave. Check your reservoir to make sure it hasn’t dropped. If it has dropped it will most likely also be a dark color. The darkness comes from the rubber seals in the master or slave deteriorating. If the fluid level is good and not dark it could still be air but probably not. Other issues could be the TOB not returning all the way. Could be a bent release fork. Could even be the pressure plate coming apart but that would typically cause lots of vibration.

[Wpomp]

Originally Posted by ermax

Yes clutch drag would make it hard to pull out of gear because it would put a little load on the gears. Clutch drag can be caused by a bunch of things. Most common would be air in the line due to a bad master or slave. Check your reservoir to make sure it hasn’t dropped. If it has dropped it will most likely also be a dark color. The darkness comes from the rubber seals in the master or slave deteriorating. If the fluid level is good and not dark it could still be air but probably not. Other issues could be the TOB not returning all the way. Could be a bent release fork. Could even be the pressure plate coming apart but that would typically cause lots of vibration.

Hmm, interesting. I bled the clutch when I changed the trans fluid a few weeks back. Fluid wasn't overly dark, but not as light colored as brand new fluid from what I can recall. I have a spec 2.5 clutch, and the forged fork, replaced TOB. Unsure. Are there any reasonably simple ways to further diagnose a master/slave seal issue?
Thanks for the info btw, appreciate it!

[ermax]

Originally Posted by Wpomp

Hmm, interesting. I bled the clutch when I changed the trans fluid a few weeks back. Fluid wasn't overly dark, but not as light colored as brand new fluid from what I can recall. I have a spec 2.5 clutch, and the forged fork, replaced TOB. Unsure. Are there any reasonably simple ways to further diagnose a master/slave seal issue?

Thanks for the info btw, appreciate it!

Did the problems start after the clutch or after bleeding? Another issue is the input shaft cover thing on the tranny gets messed up when the TOB goes bad and causes the TOB to not slide freely. I’m not sure if you replaced the TOB because it failed but if so this could be part of your problem.

One other way to see if your master is leaking is to get you hands on the shaft down by the clutch pedal and check for any fluid. When the seals go bad it will often leak down there.

[Wpomp]

Originally Posted by ermax

Did the problems start after the clutch or after bleeding? Another issue is the input shaft cover thing on the tranny gets messed up when the TOB goes bad and causes the TOB to not slide freely. I’m not sure if you replaced the TOB because it failed but if so this could be part of your problem.

One other way to see if your master is leaking is to get you hands on the shaft down by the clutch pedal and check for any fluid. When the seals go bad it will often leak down there.

Clutch was replaced in January when my TOB shit the bed in spectacular fashion. Issue wasn't noticed until ~1.5-2 months ago, so if it was TOB caused damage, I would have expected it to have started earlier.
Ah, good idea, I can check that for sure. Honestly, I may just replace the slave and the line going to the trans just as preventative maintenance. The issue isn't constant, and doesn't prevent me from dailying the car. Not a ton of money to help narrow down the problem.

[Jay Laifman]

I am having this same issue after the Toyota dealer changed our TOB on our 2018 GT. When the car is cold in the morning for the first few miles, 1st and 2nd are not good. Very notchy, and going into 2nd sometimes feels totally blocked but will ultimately let it in with a hard pull. It was NOT doing this before we brought it in.

But once warm, it shifts beautifully, all gears.

My current theory has been that the mechanic put some lube on the input shaft that is too sticky and causes the pressure plate to stay too close to the flywheel. Then once that lube warms up, it all flows better. I've also seen pictures on this site of the splines on the clutch disk getting bunged up when someone slammed in the transmission. That could cause issues - but I would expect those would not be heat dependent.

The dealer claims that they did not change the transmission fluid or touch the clutch hydraulics. I assume taking off the slave and letting it hang would not cause air to sneak in.

But, just in case, I can bleed it this weekend. I'm wondering does anyone have the measurement of the movement at the slave cylinder on a completely stock set up? I have the measurement of the pedal motion (110 - 115 mm at the pedal face). But nothing on the slave end. Does anyone have that?

[Jay Laifman]

Also, is anyone willing to measure the throw of the clutch slave when the clutch pedal is depressed? It would be interesting to know if ours is shorter than what others have.

And does anyone know if the factory workshop manual says the input shaft splines are supposed to be lubricated at all? And if so, with what? I know that some cars say no lube there.

[Jay Laifman]

I found the 2012 manual on this board. On page MT-40, it says that the input shaft splines should get Nichimoly TC5. Anyone have any idea what that is?