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High RPM shifting problems

33K views 22 replies 15 participants last post by  Trevelyan 
#1 ·
I just recently purchased a bunch of mods for my 2012 5.0, After all the installation was done the car ran good and everything but now I'm experiencing problems shifting into 3rd and 5th at high RPM's idk why I've heard it could be the clutch, shift knob or the synchronizer somebody have any clues

Mods: 302 Boss intake manifold, Steeda cold air intake, Borla XR-1 long tube headers, Borla full ATAK exhaust system, SCT Tuner


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#4 ·
Syncro's toasted.....

Maybe Dennis will come along and chime in. (you are new here so 1st thing, Welcome aboard, 2nd thing Dennis is kinda the boards know a bunch with manual tranny's, and tearing them up, errrrrr fixing them so they DONT tear up)

You can check the tech articles and look for the thread by him. (under transmissions)
 
#7 · (Edited)
Generally modern manual transmissions do not shift as smoothly and are more notchy than those trannys of the 60's, 70's and early 80's. High rpm shifting is not always easy on the new ones above 6K without some internal modifications.

The advice you have been given is all true though. You might correct it with a clutch adjustment (could have a stretched cable), it might have a shifter issue (could be external at the top of the tailhousing or an internal problem) or you could have ground away the syncronizers and the gear's engagement teeth. These issues affect all manual transmissions, no matter what brand.

Unfortunately I am not familiar with your specific tranny to make any internal recommendations. Sorry. You might want to also ask this question on The Corral as there is a lot more web traffic there and you are more likely to find someone who has had the exact same issue with their newer 5.0.
 
#8 ·
The newer 5.0's use a Chinese transmission that there seem to be a lot of issues with. As Dennis said, check out the Corral for more specific information.

That being said, you indicated your only problems are with 3rd and 5th. Those are 'reaching' gears. I have a feeling, it could be your driving. Your clutch timing may be off when reaching for those gears. You've got to clutch first, and then keep the clutch fully depressed until those gears are fully engaged.
You need to slightly lead with the clutch. In other words, your clutch foot is moving before your hand, and then it can't come up until the transmission is firmly in the next gear. It takes a lot of practice to get it fully down to a science. Most people don't lead with the clutch enough.

However, if you keep grinding/missing them, you will wear stuff out to the point it needs service.

Good Luck!
 
#13 ·
The newer 5.0's use a Chinese transmission that there seem to be a lot of issues with. As Dennis said, check out the Corral for more specific information.

That being said, you indicated your only problems are with 3rd and 5th. Those are 'reaching' gears. I have a feeling, it could be your driving. Your clutch timing may be off when reaching for those gears. You've got to clutch first, and then keep the clutch fully depressed until those gears are fully engaged.
You need to slightly lead with the clutch. In other words, your clutch foot is moving before your hand, and then it can't come up until the transmission is firmly in the next gear. It takes a lot of practice to get it fully down to a science. Most people don't lead with the clutch enough.

However, if you keep grinding/missing them, you will wear stuff out to the point it needs service.

Good Luck!
X2 Mike is right on with this. I had to figure this out for my self when I bought my Cobra the previous owner had a very heavy clutch in it. To get clean shifts when racing I had to move the seat up a inch or so and use a rediculous lead time on the clutch. You said that you just instaled new parts on your car. Did you mess with the clutch, shifter, or transmition? What parts did you install?
 
#11 ·
The most important thing you can do is drive several miles before you do much shifting at all. I know that sounds weird but if you can just ease it down the road until it's nice and warmed up before you do any fast shifting. Once warm it should shift nicely at all RPM's. Remember this trans likes to be shifted fast, once it's warm.

I have 23,000 miles on mine so far and it's perfect. But, I do warm it up EVERY time I drive it before doing much shifting.

This is from last Friday at a little track near me called Laguna Seca. ;)

Shelby Laguna Bowl 2012 Final Session - YouTube
 
#12 ·
I mentioned my 66 fairlane, 390 top loader 4 speed to speed shop owner that I could get third gear at drag strip sometimes, sometimes it would go. He stated if I shift under 5000 it will go, any rpms above 5000 it would not go in until rpms went below 5000. The spring load I beleive in tranny pervented the high rpm shift and said he could fix it if I liked. I said no , not planning on running that car at 5000 shifts. So it has to be the spring not allowing the the trannyto go into gearafter 5000, so thats what was my deal. Hope it helps.
 
#15 ·
I hurt the 2nd synchro about my 10th trip down the dragstrip in my 06... was like hitting a brick wall when trying to grab 2nd at over 4k, even started locking out in everyday driving... put up with it for about a year, stayed away from the track as knew it wasnt gonna get me home if I beat on it much more...on advice from a guy on one of the mustang forums, drained the tranny and refilled with royal purple synchromax- figured worth a shot before pulling the tranny.
immediately tranny felt completely different, would literally fall into third...within a hour of driving, the second gear issue completely went away, had been 1/3~1/2 of the time it would not get into 2nd first try just driving to work... probably another 60-80 trips down the track banging 2nd at 6k, only twice had a slight grind or catch when grabbing second...
never been a believer in magic oils, but the old 5 speeds sure like that RP oil! its kinda pricey for oil, but compared to a teardown, might be worth considering. No exaggeration, it made my hurt tranny BETTER than new at high rpm shifting, AND somehow hid whatever damage I'd done to it- good stuff.
 
#17 ·
The problem with high RPM shifting is the clutch. Go to BossMustangsOnline and you'll read all about it. The pressure plate is not letting go completely, making the syncros try to mesh under less than ideal circumstances.

BTW I totaled my car at the track and got another one just like it. It has high RPM lock-out. I'll likely get a Centerforce or McLeod RST or RXT for it.





 
#18 ·
The issue you are having is your mounts are too soft, get some stiffy rear differential/tarnsmission mount.

What's happening to your shifter at high Rpm is that it is shaking vigorously, you should be able to easily shift it though and this is not something you should take it to the dealer. What are they gonna do, rev your car over 6,000RPM for 30 minutes and come back saying everything is fine?

 
#19 ·
The issue you are having is your mounts are too soft, get some stiffy rear differential/tarnsmission mount.

What's happening to your shifter at high Rpm is that it is shaking vigorously, you should be able to easily shift it though and this is not something you should take it to the dealer. What are they gonna do, rev your car over 6,000RPM for 30 minutes and come back saying everything is fine?
were do come up with this know how stuff ?
 
#21 ·
The information you have be situated given is all true however. You might precise it with a clutch alteration (could have a stretched cable), it power have a shifter issue (could be external at the top of the tailhousing or an internal problem) or you could have ground away the syncronizers and the gear's engagement teeth. These issues affect all manual transmissions, no matter what brand.
 
#22 ·
The information you have be situated given is all true however. You might precise it with a clutch alteration (could have a stretched cable), it power have a shifter issue (could be external at the top of the tailhousing or an internal problem) or you could have ground away the syncronizers and the gear's engagement teeth. These issues affect all manual transmissions, no matter what brand.

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