SPF Shifting Trouble, TKO 600.

ou812545 · #1 (**permalink**) 02-23-2010, 12:30 PM

Jim,

Do you know if the grinding happens when the engine is warm or cold?

My car goes into reverse smoothly when it's cold, but grinds when it's warm.
I have tried putting it into first then reverse or second then reverse. It doesn't help.
I have also tried with the car in the air to see if the wheels spin with the clutch in and the wheels don't spin.
I spent several hours at the transmission shop adjusting the clutch with no luck.

I'm ready to try UltraShift from Cobra Valley even through I don't think it will fix the problem.

If you find the problem and how to fix it please share...

jhv48 · #2 (**permalink**) 02-23-2010, 01:19 PM

Well, I called the Tremec help line and the tech told me that there was no way the symptoms I have are being caused by the transmission. The input shaft has to be turning in order for reverse to grind. Putting the trans in any forward gear before reverse will stop all shafts from turning in the transmission and reverse will engage smoothly IF the clutch is fully disengaged.

Since it still grinds, it HAS to be clutch related. I'm going to replace the clutch, resurface the flywheel and then put it back together.

If it still grinds, time to disconnect the neutral safety switch and start the car with the clutch in and the gear selector in reverse.

tkb289 · #3 (**permalink**) 02-23-2010, 01:56 PM

Quote:

Originally Posted by jhv48

Well, I called the Tremec help line and the tech told me that there was no way the symptoms I have are being caused by the transmission. The input shaft has to be turning in order for reverse to grind. Putting the trans in any forward gear before reverse will stop all shafts from turning in the transmission and reverse will engage smoothly IF the clutch is fully disengaged.

Since it still grinds, it HAS to be clutch related. I'm going to replace the clutch, resurface the flywheel and then put it back together.

If it still grinds, time to disconnect the neutral safety switch and start the car with the clutch in and the gear selector in reverse.

Jim,

Interesting that Tremec says put the trans in any forward gear, before reverse ... which is what I have done with all of my stick shift cars. In my case, I usually put it in 4th gear, then into reverse (clutch fully disengaged of course). Guess it really doesn't matter, just force of habit.

Sounds like you are close to finding root cause, keep us posted.

jhv48 · #4 (**permalink**) 05-05-2010, 11:41 AM

As a follow up.

The solution was to replace ONLY the pilot bushing. Everything else was in perfect order. For some reason, the input shaft was dragging slightly on the bushing even when the clutch was fully disengaged causing the input shaft to keep turning, thus causing the grinding in reverse.

kitcarbp · #5 (**permalink**) 05-23-2011, 11:50 AM

JHV48, Is it still problem free after intalling the pilot bearing instead of a pilot bushing ?

jhv48 · #6 (**permalink**) 07-05-2011, 08:07 AM

Nope, I had to pull the tranny again and gave a new mechanic a shot. He found that the throwout bearing was a bit worn because the angle of the slave to the fork was about thirty degrees off parallel. Thus, the slave was pushing the clutch fork at an upward angle, rather than straight.

Everything else was fine. I now have about 1200 miles on the last fix and so far, all seems better. Shifting into first at a stop is smooth and shifting into reverse when cold is noise free. However, hurried shifting into reverse when hot (like having to parallel park) still produces a substantial grind in reverse no matter how many gears you put it in first.

So, I disconnected the neutral safety switch and just start the car in reverse when I need to back out of a parking spot.

Might try a hydraulic throwout bearing next time the trans comes out.