2006 mustang gt wont go into gear while running.

[BumblebeeGT]

I recently dropped a new 4.6l 3v engine into my 2006 mustang with a manual transmission and it starts up fine, but when I try to put it in gear it wont let me enter any gears while its running(I can go into any gear while the car is turned off). when I try to start it in first with the clutch pushed in it tries to lurch forward. I've spent hours trying to vacuum the air out of the clutch line but that doesn't seem to be doing anything. Does anyone have any tips or ideas to this issue I have run in to?

 

[stkjock]

stock clutch and slave?

miles on clutch and slave?

 

[BumblebeeGT]

clutch is aftermarket and the slave cylinder is stock. there isn't much mileage on the clutch because my old engine went out not long after I put the clutch in, but the slave has roughly 145k miles on it.

 

[stkjock]

general rule around these cars is to replace the slave when you replace the clutch, I'd suspect that's the culprit

how exactly did you bleed the system?

 

[rocky61201]

If your 145k stock slave was broken it would be a bad seal and fluid would be pouring out of it and onto your garage floor every time you pumped the pedal. You still have air in the system and it sometimes it can be a royal pain in the ass to get out. Keep working on it with a vacuum pump attached to the master cylinder reservoir via a rubber sink stopper from home depot. You will get it out eventually. Look for the youtube video on how to do it.

Another thing could be old dirty brake fluid. Your 2006 is 13 years old now. If your fluid is dirty and black its time to flush it. I finally got around to flushing mine last year. Made a HUGE difference in braking and clutch engagement. Bad and dirty fluid = not enough line pressure to pump up your throw out bearing.

You said everything worked before the motor went bad. If none of it broke when you blew the motor then it should work again. My guess is air in the system (still) or old/dirty fluid.

Another possibility is some of the clutch fingers got bent when installing the new motor. If all else fails and you have to remove the transmission, check the clutch fingers and replace clutch if necessary. Also replace the old TOB/slave since you're already in there. Last thing is make sure you measure for TOB preload before re-installing everything. Your ideal preload measurement you are shooting for is close to 1 inch as possible but not more than 1 inch. There is a thread here on how to measure for TOB preload and shim it up if you don't have close to 1 inch of preload. If you have an aftermarket clutch you NEED to do this procedure. All aftermarket clutch are just a little bit different. Some need a shim. Some need two shims. Some don't need a shim at all. HINT, if you only have 1/2 inch of preload your throw out bearing is only pumping up 1/2 inch. 1/2 inch is NOT enough to fully engage your clutch and take the engine load/torque off the transmission input shaft.

 

[BumblebeeGT]

well, I finally found the time to drop the transmission today and it looks like the throwout bearing was definitely due to be replaced. I would think this would be my cause for not being able to go into gear while it was running. what do you guys think?

 

[Dino Dino Bambino]

It's definitely seen better days.

 

[BumblebeeGT]

Well even with the new throwout bearing in I can't get it to go into gear while the engine is running. I've tried using the mightyvac to get the air out of the lines but that doesn't seem to be working. Any other ideas?

 

[nbk13nw]

I had the same issues a long time ago. The syncos would be suspect. Pro-Force Performance out of Georgia built me a new one with upgraded forks, syncro's, etc.. No issues since that time

 

[BumblebeeGT]

I don't think anything is faulty with the transmission it was working fine before my original motor blew. But I guess that is a possibility. I'm kind of stumped at this point.

 

[projectHCslayer]

i just had the exact same issue turns out i put my clutch disc in backwards.

 

[rocky61201]

Even with bad synchro's you should still be able to force it into gear while the car is at rest and idle. Fourth gear would be the easiest as it is 1 to 1 ratio. Did you inspect clutch fingers when you had everything apart and did you measure for ToB preload? What brand flywheel and clutch are you using? Is it an old worn out flywheel that has been resurfaced a couple times? If enough material has been worn and shaved off during resurfacing that will affect how much extra travel your ToB has to make to properly engage clutch. A couple bent clutch fingers will affect proper ToB engagement as well. Last thing is to check under the dash and make sure the clutch pedal doesn't have any extra play or is "loose" where it connects to the master cylinder push rod.

If everything mentioned above has been checked, the last thing in the system to inspect/replace is the clutch master cylinder under the dash.

 

[BumblebeeGT]

My clutch set up is all exedy. Everything looked fine to me besides my pressure plate being rusty, so I went ahead and put a spare new exedy pressure plate on that I had laying around. I did notice that when we were installing the tranny back on when the throwout bearing made contact with the pressure plate, it spit some of the brake fluid out of it. Do you think that would be enough to cause my issue, even with all the vacuuming I've done on the system?

 

[rocky61201]

Not in the least, it's impossible not lose some fluid during the install. Even with the hose and ToB bearing capped (I use a vacuum cap) as soon as you take them off to connect the two some will definitely spill out. Especially if your face is right under it. I don't know what to tell you honestly.

I've replaced the clutch or had to take the transmission out at least half dozen times over the past few years. Sometimes I have to bleed with a vacuum pump, sometimes I don't. But the way I do it is with the vacuum pump hooked up with a rubber sink stopper from home depot and cut a hole in the middle of it to stick the tube thru.

Then I press that rubber stopper into the master cylinder reservoir to get an air tight seal. Pump up the vacuum to about 20psi and hold for about 30 seconds. Release vacuum and then get inside and start pumping the clutch pedal. Repeat as many times necessary. Never had to do it more than 2/3 times.

If all else fails jack the front of the car up some to incline the car and help with air bubbles rising to the top. This trick goes for refilling an empty radiator as well btw. Gets the coolant reservoir higher than the engine.

 

[rocky61201]

Just thought of 1 last crazy thing. Was your car parked for awhile waiting for the new engine? Maybe something got in the clutch line???? Bugs, spiders, spider webs maybe????

You mentioned in another post your could get into gear when the car is off, then start the car and it lurches forward. That alone is proof nothing inside the transmission or gear linkage is broken to prevent you from getting into gear when car is running. It's gotta be something clutch related.

Good luck brother, I know how you feel.

 

[golkhl]

Inspect your clutch master cylinder, only visible sign of failure will be fluid leak. If you replace it, consider upgrading to the 2013 GT500 clutch master cylinder.

 

[BumblebeeGT]

It did sit for a while before I was finally able to swap the motor in, but wouldn't I have been able to see signs that it had debris in the fluid when I was vacuuming it out and moving the fluids around?

Also, I have tried to inspect the master cylinder, but it has no visible leaks. Is there a way to check on if anything failed internally in the master cylinder? I've never had to refill my brake fluid from it leaking from somewhere.

 

[BumblebeeGT]

I replaced the clutch master cylinder and got the mcleod braided steel clutch line while I was doing that. That still didn't help though. I guess the only thing I have left is to drop the tranny and look at the clutch again.

 

[Dino Dino Bambino]

Either the slave cylinder is bad or you installed the clutch release fork incorrectly (or forgot to install it altogether).
You'll probably start kicking yourself when you discover the problem after you've removed the tranny.

 

[mikek2111987]

Inspect your clutch master cylinder, only visible sign of failure will be fluid leak. If you replace it, consider upgrading to the 2013 GT500 clutch master cylinder.

What sort of benefit does this give? Direct swap?