[Resolved-ish] [Transmission] Hard to put into gear from dead stop
 

Hey all, I've got an issue with my '14 FRS and wondered if you have any experience.

I often have a very hard time putting it into gear from a dead stop (any gear R through 6) right from clutch in.

• If i clutch in and quickly try to engage a gear, the car will roll a little as transmission inertia is taken away by the synchro locking up. However, it won't enter the gate.
• With the clutch in, if I hold the shifter at the gate lightly for several moments, the gear will eventually engage as everything stops spinning. Racing the engine to 3k RPM appears to help somewhat, but results are inconsistent.
• Alternatively, if leave the clutch in for some time (5-10 sec), it appears everything stops spinning and the gear will engage. However, at stop lights and traffic, this can be problematic.
• I've also noticed that sometimes when coming to a stop in gear, with clutch in, there is a resistance to pulling the transmission out of its current gear into neutral.

Right when I start the car, it has no issues. I also have no issues engaging any gear if the car is already rolling (e.g. 1 MPH or higher). This only occurs at dead stop.

• Symptoms appear when I start driving for a little. Symptoms remain until I park the car for a while and it cools off.
• Symptoms have surfaced fairly recently, and the local weather has become quite hot (So Cal, 105 deg F+ ambient)

I put the car in both first and reverse with the clutch fully depressed. I revved the engine out to near redline on a level surface (my garage), and the car did not budge.

I'd appreciate any help/insight.

--------
*****EDIT 1 (7/11/2018)
I put the car on jack stands for a more sensitive clutch drag test:

• With the parking brake on and clutch in, the gear was hard to gate (as before). I also noticed that the engine speed was responding and dropping slightly despite the clutch being in
• With the parking brake off and clutch in, the gear engaged smoothly. At first the wheels only spun a few revolutions, but quickly came to a stop.
  • However, I also began to notice intermittently that the wheel would continue spinning while in gear with the clutch in at idle engine speed. This did not occur on every engagement, but occurred often enough not to be a coincidence.
  • Also, wheel spin would occur at the same rate/sensitivity regardless of how far past the friction point the clutch was pushed in. In other words, the drag appeared to be consistent across the dead pedal throw depth.
  • Nuance with this dragging incidence: when racing the engine, wheel speed did not increase appreciably or would decrease momentarily until RPMs returned to idle. Sometimes, the wheels would stop spinning after racing the engine. This might explain why primary clutch drag tests turned out negative.

Based on these conclusions, I might be observing some drag due to the throw out or pilot bearing?

I don't have any grinding or shifting issues while the car is in motion or when the wheels are free to spin. Again, only happens when the car is hot.

--------
*****EDIT 2 (7/19/2018)
I also tried adjusting the clutch pedal to get more travel at the fork. This did not appear to resolve the issue.

I also bled the clutch cylinder and put in new fluid. This also did not resolve the issue.

--------
*****EDIT 3 (10/16/2018) Resolved-ish
Drove on it for a few more months without any real improvement. Also noticed some screeching coming from the bell housing when the system was hot from spirited driving, in gear, in motion, and on a downhill.

A few weeks ago, I pulled out the ACT clutch kit and re-installed the OEM clutch kit. I haven't had any problems since.

Upon initial visual inspection of the ACT kit, nothing appeared wrong with it. Throw out bearing and pilot bearing spun free. No damage on the input shaft

I sent to back to ACT for evaluation, and they say they didn't find anything wrong with it either. They seem to think it's the clutch hydraulic system/supporting components on the car. Might have been a spline grease issue.

In the end, nothing conclusive. I'll keep the OE kit in the car a while and do another clutch job when I feel like I need to. I likely won't put the ACT kit back on the car.

------------------------------------

Relevant mods:

• Velox/Verus Forged 4130 Clutch Fork
• Velox/Verus Billet Clutch Pivot
• MTEC Shifter Springs
• ACT HB7-HDSS (Stage 1 Street Clutch /w Streetlite Flywheel)
• Whiteline Transmission Mount Bushing
• Motul Gear 300 Fluid, supplemented with Toyota OE Gear 75w90

Clutch was installed about 4 months/5k+ miles ago. Clutch was broken in for about 1k miles before driven hard. Last time the car was tracked was 3 months ago.

It is clutch drag, but it seems to happen only when the whole thing is fully hot. I have the exact same mods as you, minus the shifter springs and and trans mount bushing. When its giving you trouble, put in a flat surface and try to engage fist gear without pushing on the brakes, watch your car slowly move forwards while still not letting you into the gear. I had the problem before the clutch fork and pivot was installed, also had it with another clutch before the ACT with lightweight flywheel went in. One last test, when its not letting you in, clutch in, wait about 3 seconds, give it a quick rev to around 3-4k and put the gear in while rpms are dropping, it will go in. Its a weird quirky thing but it seems to me like clutch drag, altho when they measure everything it always checks out, seems to happen only hot.

When you are in neutral with the clutch out it will spin the input shaft. If you then press the clutch in and rush right into 1st the car will lunge a tad if you don't give the input shaft time to spin down. This is all normal. You should only be concerned if you clutch in, wait for the input shaft to come to a rest and then still get a lunge when going into 1st. That would indicate your clutch isn't fully disengaging.

That is exactly the problem, I can keep the clutch in for over a minute, still wont go into gear, and tries to move forward when I push the gear in (holding it with a certain presure agaisnt the gate, it doesnt go in, car keeps moving forwards, not a small lurch, but a slow continuous movement). Im not rushing into gear, neither is him probably. Not normal at all, it is clutch drag for sure.

Okay but that isn't the description the OP gave. In your case I agree you have a clutch issue. Air in the line, TOB on it's way out or something else breaking on the clutch preventing it from fully disengaging. One thing I do to see if it's dragging is jack the rear wheels off the ground so there is no resistance and watch to see if they turn while the clutch is in.

Yes, I have this behavior a little bit, but the car doesn't keep rolling. It just moves a little bit then stops.
This sometimes works, but results for me are inconsistent. It takes about the same amount of time for me to wait for the input shaft to stop as it takes to rev the engine for effect.
My specific problem appears to be that if there is any signification rotation of the input shaft, the gear is difficult to engage. It's as if the synchros lock-up rather than mesh and gate the gear.
Like you mentioned, everything works fine if I wait for the input shaft to come to complete rest. The gear will glide in as expected. However, this isn't convenient when I'm at a stoplight in traffic.

That definitely sounds like clutch drag, but I'm not experiencing continuous movement. Eventually the car stops for me, and if I hold it just a bit longer lightly, the gear will gate.

Quote:

Originally Posted by ermax (Post 3108594) Okay but that isn't the description the OP gave. In your case I agree you have a clutch issue. Air in the line, TOB on it's way out or something else breaking on the clutch preventing it from fully disengaging. One thing I do to see if it's dragging is jack the rear wheels off the ground so there is no resistance and watch to see if they turn while the clutch is in.

This is a great idea as well. I'll try this out next time I get the car on stands and verify that it isn't even minor drag.

---
Appreciate all the feedback/discussion so far!

I skipped over the part where his car stops rolling, my bad there. In my case, I have flushed the system several times, installed a braided clutch line, brand new release bearing, and nothing seems to change at all. If anyone else happens to know exactly what the problem is, I may be able to fix it eventually.

I'm not really sure why you never experienced this in the past though. If the input shaft is turning then it's going to propel the car forward when you put it in gear. The only thing I can think of that would exacerbate this would be maybe you changed tranny fluid so something that lets the internals spin more freely for longer and/or maybe your tune raised your idle a little causing the shaft to spin longer. The syncros really are irrelevant with regards to the car moving though. If the input shaft is spinning and you lock it to the output shaft then the car will move. If your having difficulty putting it into the gear then yeah that could indicate the syncros are wearing. But the variables I listed (fluid and/or idle speed) could also impact the syncro's ability to work.

If the symptom appears only when it is hot, may be there is an air in the system or your master and or slave cylinder is not working properly.

I would try bleeding the clutch and adjust the engagement point to make the grab point higher. The higher grabbing point the less chance that your clutch will drag because you get higher clearance by setting the grab point higher.

I had similar symptoms with my '13 FR-S w/ ACT HDSS-SB7 + Verus Fork. Could never get it into gear from a stop when the car was warmed up. Bled the clutch fluid, replaced the slave, but in the end, I could never figure out why before moving on to the BRZ.

I occasionally have similar trouble getting into 1st at a stop. It takes a lot of force to get into 1st gear. It's not a permanent solution, but when it happens I engage 2nd gear, then go to first all while the clutch is disengaged. Going into 2nd seems to move things around enough to make it easier to engage 1st.

Yep, that was an old school strategy with non-synchronized transmissions ...:thumbsup:



humfrz

I’m curious if you would get the same effect by simply letting out the clutch in neutral for a sec, press it back in, let the input shaft spin down and then try first again. This is what I do in all my cars when reverse is stubborn. But then again reverse is straight cut with no syncro.

Added an update to the original post, below:
I put the car on jack stands for a more sensitive clutch drag test:

• With the parking brake on and clutch in, the gear was hard to gate (as before). I also noticed that the engine speed was responding and dropping slightly despite the clutch being in
• With the parking brake off and clutch in, the gear engaged smoothly. At first the wheels only spun a few revolutions, but quickly came to a stop.
  • However, I also began to notice intermittently that the wheel would continue spinning while in gear with the clutch in at idle engine speed. This did not occur on every engagement, but occurred often enough not to be a coincidence.
  • Also, wheel spin would occur at the same rate/sensitivity regardless of how far past the friction point the clutch was pushed in. In other words, the drag appeared to be consistent across the dead pedal throw depth.
  • Nuance with this dragging incidence: when racing the engine, wheel speed did not increase appreciably or would decrease momentarily until RPMs returned to idle. This might explain why primary clutch drag tests turned out negative.

Based on these conclusions, I might be observing some drag due to the throw out bearing?

I don't have any grinding or shifting issues while the car is in motion or when the wheels are free to spin. Again, only happens when the car is hot.