Brand new syncros but gears are still grinding?

Hi all, so I am only 20 years old and I pretty munch finished the restoration on my 69' dart swinger 340 4 speed about 2 years ago and I've been trying to fix the issues I've been having with shifting on my car as I've had the time and money and I just can't figure out what's wrong. Every time I shift up a gear it grinds a little bit, down shifting it grinds so bad I pretty much cannot get it into gear and when it gets into second I can go about 100m before it pops out regardless if accreditation or deceleration. I have the correct bellhousing, correct shifting linkage fully adjusted, all brand new and correct clutch linkage which we have adjusted properly, have about 2 inches of pedal play before clutch engages, transmission has been rebuilt been gone through multi times by different people and nothing has been found wrong, brand new syncos, even replaced the second gear with a slightly better used one out of another trans I have, brand new clutch and freshly machined flywheel, I have tried about 3-4 different types of gear oil and I have just run out of ideas. I have replaced a lot of parts and changed/adjusted a lot of things, and it has gotten a lot better than it originally was but it still has the same issues. I really just want to finally be able to drive my car around without having to worry about the trans. Thanks in advance for the help. Attached photo is a picture of my car.

What adjustments have you made that have improved it somewhat (as you mentioned). I ain't a stick guy so this is a BTT to get some dialogue going but 2" seems (to me) like alot of freeplay. I'd lengthen the rod & see how it acts with that. With the pedal depressed what is the disc to flywheel clearance?

It sounds like a clutch problem, especially if it's in all four gears + reverse.

Or a clutch adjustment problem. Tighten up for much less freeplay.. maybe 3/4".

Is your 2" of play before the throwout bearing engages the pressure plate or 2" off the floor before the clutch starts to grab?

What weight gear oil are you running?

My clutch instructions stated 1" MAX freeplay.... Good luck and nice looking Dart.

I agree with all the replies so far. It sounds like a clutch issue. I'd try adjusting the free play so you have about 1/4" at the clutch fork. This should give you about 1" at the pedal. If you still have a problem after doing this, there maybe an issue with the pilot bushing being too tight, or the trans bottoming out in the crank.

you need to check if the clutch disc is free from the flywheel with the pedal fully depressed. have someone depress the pedal and look and see how much air gap you have between the disc and the flywheel. there are specs published, but off the top of my head .040 seems to ring a bell. you can check that with a feeler gage. make sure the car is supported properly for this check while you are underneath it.

Is does sound clutch related but out of curiosity what types of oil have you tried? GL-5 oil is for rear ends, GL-4 is for trannys. GL-5 will cause some grinding on occasion because of the extra friction modifiers that are added, it doesn't play well with the brass syncros and the gear hubs.

1" of play at the pedal has always been the norm.

There are a lot of variables that will affect how much pedal free play one has. What is critical is whether the disc has adequate clearance when depressed. while checking it is a good idea to verify that it is the same in several locations by rotating the motor around.

I agree about .060" works good.

Mopar are a pain in the rear to get the clutch linkage adjusted properly Remove the clutch splash sheild and verify that the throw out bearing is not touching the pressure plate fingers with the clutch pedal all the way up, you need at least .050 between the throwout bearing and all three fingers. Before that check to make sure and pull the clutch pedal up all the way so the over center spring under the dash is not preloading the clutch linkage at all
Once those adjustments are done let us know how you like that

ONCE you check and verify the clutch gap is OK - Then consider these suggestions..

for the popping out of gear - verify the shifter is adjusted properly and linkage and levers are tight.

If you bought aftermarket shift linkage - be advised some of it is junk.

Did the shifter pop out of gear before you changed the gear in the trans?

Make sure the throw out bearing isn't too tight or crank is undersized pinching input shaft.

Are you running a stock bell housing or aftermarket - Has anyone checked the alignment/run out?

EDIT - I should have typed be sure pilot bushing isn't too tight , instead of throw out bearing.

I have twice seen clutch discs that have been tweaked so as they are not running true when clutch pedal is fully depressed. My suspicion is that this occurs while the transmission is being installed, that Bubba has allowed it to hang unsupported before it is fully inserted into pilot bearing, thereby causing the aforementioned tweak.

If you are unable to analyze your problem and must remove the clutch for further problem determination, place the hub of the disc on a flat surface and spin it. There should be no up and down 'wobble'. If there is, it will cause a dragging clutch at disengagement.

Can you place the transmission into reverse when the clutch is fully depressed, or must you engage any other gear first. This can be a helpful clue if you are unable to go directly into reverse.

Okay thanks for all the fast replys! I was mistake and I made a mistake with the pedal free play. I guess it last night but I checked it this morning and it actually is 3/4" of pedal play before the clutch grabs. All the shifter linkage is original and the set I'm using right now is from a buddy and there's nothing worn out on it, factory 69' bell housing, I checked my gap on the clutch last year and from what I remember it was about 0.040, it still popped out on gear before I changed the gear, some of the past gear oils I used weren't proper, can't remember all the ones I used but 80 90 conoco, pennzoil sychromesh, and right now I have Lucas sae 85w-140 in it. I have been thinking clutch issues too, but haven't wanted to drop the trans for the 4th time lol, but would having clutch issues still make me pop out of gear?

It can go into reverse right away, but it's a little hard to get it into gear. Sometimes putting it into first or reverse with the clutch in it can make a bit of a grind, but usually a bit of a knock as if it putting it into is stopping the trans from moving? I'm not too sure what's going on there.

Is it the original to the car bellhousing and engine ?

It sounds like your problem is all clutch related.

Ok.. play's at 3/4". Perfect. As JohnRR said, clutch problems. MY guess the clutch is not disengaging all the way. Throwout sticking maybe, fork tweeked?

There is a rather elaborate clutch bell housing exercise that is well established protocol for those who may experience the issues that you are describing,,,particularly popping out of gear,,,,likely not a clutch caused issue,,,and gear grind which often can be.

Check out this link

http://www.hurst-drivelines.com/files/GM...%206-15-09A.pdf


For additional info , Search Google with this argument.


clutch bellhousing alignment

No response to the question if the bellhousing is original. Misaligned bellhousing equals popping out of gear and gear grinding.

Forget the pedal free play and do like the FSM says, set the play at the throwout fork at 5/32".

Awesome looking Swinger, my buddy has almost the twin to yours, his has a black interior!!!
I'm having similar problems with my 67 hemi GTX, starting to break it down to being the pilot bearing being too tight and turning the trans even when the clutch is depressed, I have had my buddy with the Swinger go through the trans it and it seems that it's real good for a while and than it starts doing the same as what you car is doing, being a nice guy that I am I believe putting some grease on the pilot shaft is creating some of this problem after a while as well as not pre reaming out the pilot bearing, what I have been reading ppl say to not put any grease on the pilot bearing at all, I have used just a dab of lithium grease, my next step is to use a bearing that goes into the A/T torque converter hub area in the rear of the crank, this should be the part number, # BRG FC69907, hope to try this in the next few months.
Good luck to you,

Alot of good replies but none of them garantee you input shaft/disc is free.
With the car running, press the clutch pedal. After 5 seconds try to engage reverse. If the clutch was disengaged it will eventually stop spinning allowing you to engage reverse.

Although my feeling is the problem is in the transmission. If you do not disengage the clutch and try to shift. The gear should not be allowed to go in. Similar to shifting without a clutch. It either goes in when the speeds are matched or it's not going in, but there is no grind.

Yup Dial the bell 1st thing. Its a PITA but Ya gotta start There. All the big trans vendors wont Warranty if out by IIRC 0.003.

Once you get it measured, then get the ROBBMC dowels that will get you realigned. I tried all of the others, its the only one that works.

after clutch work and bell alignment, i use alignment pins to help guide and support the trans when reinstalling it. they can be made by getting some bolts a couple inches longer than those used to secure the transmission. cut the heads off and grind or file a screwdriver notch in the end. using these keeps the weight off the clutch disc when installing the transmission, preventing the clutch disc from moving off center as well as preventing things such as the throw out fork from getting "tweeked". when trans is seated, remove alignment pins and install proper bolts. i use this tip on automatic transmissions as well.

You mentioned changing out the syncros, how were the dog teeth (clutching teeth) on the gears themselves? Were they redressed? Just because you changed the synrcos, doesn't mean the trans is rebuilt. I am assuming the people you had look at it knew what they were doing. If you do end up taking the trans out, pop the side cover and put up some pics. Worn dog teeth will do what you are describing as well. If the trans is a 1969 it will have the ball and detente cover so be careful not to push the shifter levers out or else you will pop out the balls and spring.

The NP833 trannys from 1964 to mid 1971 all had that side cover There are three different synchro assemblys also so they need to match the gears and hubs in the tranny

I'm a newbie on this but I cant help wondering if there is any way to pin it down to either the clutch or the trans before having to take off the bell to check runout there? But that IS what we have been trying to do here all along. keep us updated

you could check the disk gap, throw out bearing clearance and see if the input shaft is tight in the pilot bushing before you pull the trans.

Once apart you can check the pressure plate for broken parts, a bent disk and see the flywheel for a weird wear pattern

I would open the trans last

It's clutch related, and he hasn't answered the question of the originality of the block and the bellhousing .

Chrysler did the final machining of the crank main line, and the pilot hole of the bellhousing, with the bellhousing bolted to the block. The assembly stayed together from that point on. That is why there is a big cover plate on the bottom of the bellhousing, so it could be assembled with the bellhousing in place.

Most people have bellhousing that were not original to the block in the car as most cars are not matching numbers, so there is a runout issue that many do not realize they have.