TheSamba.com :: View topic - Grinds into first gear even at a complete standstill

Wed Dec 20, 2023 4:31 pm

Any reason why this would happen? I’m still struggling to try to not grind into second gear (third or fourth gear seem to be Ok), but even at a complete standstill, I would assume that I could put it in first gear without grinding.

Transmission was rebuilt wonderfully by Joe Ruiz. Clutch, flywheel and throwout bearing new. Clutch pedal play within spec.

Wed Dec 20, 2023 4:53 pm

I assume you're talking about a transmission with an un-synchronized first gear, with synchronized 2, 3, and 4. As far as I know, it's normal. The input shaft is spinning, idling in neutral. You push the clutch in and the input shaft continues spinning due to inertia. You can shift into one of the synchronized gears initially to stop the input shaft rotation, then, still holding the clutch in, shift from there into first.

Wed Dec 20, 2023 5:41 pm

Sounds like a full crashbox.

It should shift into first smoothly at a dead stop with the proper clutch free play (about a half inch at the pedal).

You say flywheel and throwout bearing are new, but what about the clutch disk itself? (Sounds like the tranny may not have been that wonderfully rebuilt.)

Use first gear just to get the car moving, and shift immediately into second at just above a creep. The car behind you may not be happy about it, but you should get some silent shifts. Double clutching is used for downshifts.

Wed Dec 20, 2023 7:20 pm

Pilot bearing, if it's stiff it will spin the shaft and first grinds, same as a clutch disc that's not fully released.

Wed Dec 20, 2023 7:44 pm

Very helpful feedback. I have a bunch of things to check up on tomorrow. I did miss in my previous post - the clutch disc is new. And yes, this is a full crashbox transmission.

And thanks for the tip for shifting into 2nd. I've been waiting way too long to shift.

Thu Dec 21, 2023 9:45 am

50Splitman wrote: Very helpful feedback. I have a bunch of things to check up on tomorrow. I did miss in my previous post - the clutch disc is new. And yes, this is a full crashbox transmission.

And thanks for the tip for shifting into 2nd. I've been waiting way too long to shift.

you don't need to shift out of first that quickly, I never do. I double clutch on the way up as well, I find it makes for faster and easier shifts. Lugging these small engines is not a good idea, they were meant to be revved.

it should not grind going into first at a stand still, something is wrong. And when you get really good at down shifting, you can downshift into first without grinding.

third and fourth are easier because the gears are helical cut, while first and second are straight cut. This is also why first and second are considerably more loud than third and fourth.

Thu Dec 21, 2023 11:10 am

esde wrote: Pilot bearing, if it's stiff it will spin the shaft and first grinds, same as a clutch disc that's not fully released.

This^^

It shouldn't grind if you are sitting still.

Early gland nuts had a sleeve bushing rather than a needle bearing so they are far more sensitive to being clean and properly lubricated. Needle bearings are a little more forgiving. I don't know off the top of my head when they switched to needle bearings.

Also a broken clutch tube in the tunnel can allow the tube to move and reduces how much you actually disengage the clutch, even if the pedal free play seems correct. If your car has a bowden tube for the clutch cable, this is another thing that can cause problems if it is damaged.

Thu Dec 21, 2023 10:42 pm

How quickly are you shifting it into first (while at a standstill) after you’ve pushed the clutch in? I’ve never driven a full crashbox car, but my splitcase with non-synchro first doesn’t like when I push the clutch in and instantly shift into first gear. It likes me to give it a second or two to let the input shaft and whatnot spin down after pressing in the clutch before shifting into first. If I do that then she’s happy. Otherwise I get a mild crunch and then I die a little inside. My Sprite also does the same thing, and it even uses needle bearings and 30w oil in the transmission. :cry:

Thu Dec 21, 2023 11:21 pm

Did you call Joe Ruiz and ask him for suggestions/advice?

Fri Dec 22, 2023 4:49 am

74 Thing wrote: Did you call Joe Ruiz and ask him for suggestions/advice?
There's no need to talk to Joe, it's not a transmission problem.
Something is turning the input shaft while the pedal is all the way in.

Sun Dec 24, 2023 2:21 pm

50Splitman wrote: Clutch, flywheel and throwout bearing new.

This is why I at first ruled out the pilot bearing. I had one go once, and the sucker resisted shifting into first gear like crazy. I'm aware that splits used a brass bushing rather than roller bearings, but I assume the later gland nut can be interchanged.

Splits normally do not have a bowden tube, but it mostly cured issues with clutch judder rather than engaging gears.

sled wrote: You don't need to shift out of first that quickly, I never do. I double clutch on the way up as well, I find it makes for faster and easier shifts. Lugging these small engines is not a good idea, they were meant to be revved,
Double clutching never helped me on an upshift, and I would shift to second above lugging speed. It's really not much of an issue because the car is barely under load at that speed. (Also, I might drive the car exactly the same way two times, and one time it would crunch and the next it wouldn't, so it's not always about technique.)

Different methods work differently on different cars. Try experimenting and see what works best for you.

Mon Dec 25, 2023 9:27 am

Are you 100% sure the engine is bolted up tight and squarely? If it's hanging a little the clutch will drag. I've seen it on a car where the engine seal got caught in the bell housing.
What clutch pressure plate? I chased my tail with a "new" SACHS that would not fully release. It "almost" lets go, but just drags a little. In the end I rebuilt an old 3 arm pressure plate and used that

Mon Dec 25, 2023 7:45 pm

I have run into a similar issue, a few times on later Bugs. It always turned out to be sloppy machining of the flywheel. There is a critical distance from the pressure plate bolting shelf to the disc surface areas. I do not remember what it is, but it is in the Bentley manual!

Tue Dec 26, 2023 8:59 am

VW_Jimbo wrote: There is a critical distance from the pressure plate bolting shelf to the disc surface areas. I do not remember what it is, but it is in the Bentley manual!
24.0mm for a 6V flywheel

Thu Dec 28, 2023 9:20 pm

Thanks everyone for your insight. I was able to get started troubleshooting more today after the holidays and some pretty nasty weather had cleared.

At this point, I found that taking some of the play out of the clutch adjustment seemed to help get rid of the grinding most of the time. I also worked a bit more on double-clutching and shifting slightly slower and it has smoothed out the overall shifts. To answer a previous question, I have an F&S three-finger pressure plate:

I didn't pull the engine, the picture above was taken before I first installed it. I checked that the engine was mated evenly to the transmission bellhousing, and it looked good. I also at one point had full visibility into the chassis tunnel from the other side of the pedal assembly since someone cut a large hole, and the clutch cable tube was in good condition and not broken off its welds.