My 4 speed swap works flawlessly, EXCEPT.....it grinds going into reverse. I have tried the "go into second" before reverse, and it still grinds a little. :ball: Sounds like the reverse gear is spinning when the trans is in neutral. It's a M21. Any ideas?????? TIA
What rpm are you at when you put it in reverse? I found that the lower the rpm the smoother it will go in. I put in all of my transmissions 2 small posi lube's and that seemed to make the trans shift smoother too.
You've gotta wait sufficient time for the gear set to spin down before going to reverse. Just can't be helped.
Brad is correct! :Smarty: It just cant be helped. Its a Muncie thing. Ive got into the habit years ago to just put it in first gear first, then reverse. It never grinds doing it like that. I was told that it "lines up the synchros" although reverse is not synchronized. Whatever the reason, putting it into first, first or letting it spin down a little does the trick.
I hope you guys are right.....I am about out of adjustment. It's a Center Force II clutch.....and it could be a defect. I will also try to re-adjust the shift linkage again. Putting it in first or second for 30 seconds does nothing for me....It still grinds. I have owned a bunch of GM A body cars with Muncies, and this has never happened.
Another thought. Did you indicate in the bell to the crank? A mis alignment can cause the input to turn with enough drag torque for reverse to grind but the first and second syncros can overcome the drag torque. If it's been done, never mind. :laugh:
I did not indicate the bell to the block. Hindsight being 20/20, I should have. The tranny slid right in, as it has never done before. My feeling is the clutch disc is somehow hanging on the flywheel. Just enough to spin the input shaft enought to keep the reverse gear from slowing down. I am going to mess with the linkage, but it appears that I will have to pull the tranny to see what is wrong....... ou:
UPDATE: Doing some research and talking to Center Force, it appears that the mechanical leverage that the stock set has is not enough to deflect the diaphragm enough to totally release the clutch disc. The set up is the Center Force II pressure plate and disc. It has about 60% more clamping force than the stock clutch. It makes sense that it will take more mechanical leverage to compress it. I am looking into an adjustable pivot ball. That should give me enough leverage. The bad news is I have to take the whole thing apart again....... ou:
Ahhhh....that would certainly account for your problem. Look on the bright side, think of how much faster it will come apart and go back together the second time! :laugh:
REWORK = Doing something twice that should only have to be done once.... :rant: :rant: :rant: :rant: :rant: :rant: :rant: :rant:
I should have chimed in. I had to use the adjustable pivot ball when I used that same clutch in my skylark. A word of advice though when you get your height correct --- dont trust the jam nut method--locktite it . Guess how I found out that was important !!! George in DC
Another thing I would check is the reverse gear synchronizer. If that is warn, it will be very difficult to go into reverse.
Tranny is all new, and rebuilt by a top shop (Ed Hartnett 4 Speeds). All the linkage bushings and clips are new. The shifter mechanism was rebuilt by Hurst Probable causes: 1. Misalignment of the bellhousing 2. Clutch disc hanging up on the flywheel bolts 3. Binding pilot bearing 4. Clutch fork pivot too short for the aftermarket clutch - not enought leverage to deflect the diaphragm I will be pulling the tranny this weekend, and will post my results.
Update Spent an hour re-adjusting the shifter linkange and the clutch linkage. Drop the car down and start her up. Goes into reverse easily...no grinding!!!!! :laugh: I take he out for a ride....come home and go to put her into reverse...grinds...... :rant: So, I have concluded that the "Coefficient of Thermal Expansion" is somehow causing a slight interference to cause the clutch to not totally disengage. The dissection is underway - Results to follow!
You also need to know that reverse has NO cincro"s It will not PAD the shift like the forward gears. So it has to grind in theory.
Yup, no synchros in reverse...BUT, if you put it into a forward gear, the reverse gear should be still. If the input shaft is spinning AT ALL, the reverse gear will be spinning as well. My tranny guy is convinced that the clutch disc is not disengaging 100%. I will have the tranny out in about an hour.
Found the Problem!!!! I pulled the trans last night to figure out what the issue was.....the input shaft was just touching the back of the crank. Just enough to keep the clutch disc moving with the pedal in. And enough to keep the reverse gear moving. A little surgery on the input shaft is all I needed............. :laugh:
