The Stovebolt Site Forums The Shop Area Driveline Grinding first gear

I just recently got my 58 Apache 32 on the road. It came to me in pieces and I just completed putting it all together this weekend and took it out on the road for a test drive. It has a 235 with a 3 speed column shift. The problem I am having is that it grinds in first gear when the clutch is pushed in but only when I come to a stop while driving around. It only seems to do it while out driving. If I drive back and forth in forward and then in reverse in the driveway all seems good with no grinding going into first gear from reverse with the clutch pushed in. If I go out on the road and drive I can switch gears fine from 1 to 2 and to 3. I can down shift from 3 to 2 with no problem but I can't go from 2 to 1 without grinding gears. I tried double shifting and that won't work either. When I come to a stop sign I push in the clutch and come to a complete stop and try to shift into first and it won't go into first without making a buzzing grinding sound of gears not wanting to mesh. If I sit at the stop sign for a length of time (say 30 seconds) with the clutch pushed all the way to the floor I can then shift into first gear with little to no grinding. So I'm confused as to what what is causing the problem. My first thought was that the clutch must not be separating with the pedal pushed in so I took off the dust cover so I could get a look at the clutch and its separating about 1/8" when the clutch pedal is fully depressed. I messed around with the nuts that adjust the "free clutch pedal movement" adjustment and all that seem to do is move the point at which the clutch grabs in the pedal stroke. Is an 1/8" of separation in the clutch enough when the pedal is fully depressed? If not how do I adjust that? Does the pivot ball the clutch fork pushes against control this? Or do I have a transmission problem? Any advice greatly appreciated!

Non-synchro 1st gear. Normal.🛠

Thanks for your reply. I thought Non-syncro gears explains why I can't down shift from 2nd to 1st while moving. But I thought I should be able to do that by double clutching, or so I have been told. But my problem seems to be more than that, I can't shift into 1st without grinding gears AFTER coming to a full stop and with the clutch pedal pushed to the floor. I don't understand how this could be a non-syncro gear issue.

You probably have a slight drag between the flywheel and the clutch disc when the pedal is fully depressed. Here's a sneaky trick. At a stop, put the shifter into second gear, THEN quickly pull it back into 1st. without any hesitation in the neutral gate. It will drop right into gear with little or no grind. If the problem is from lack of exercise of the clutch, the problem should clear up within a few miles of driving as the parts develop a running fit with each other. Engaging 2nd. momentarily stops the cluster gear from spinning, which is probably what is causing the grind.
Jerry

Sitting still, engine running, a grind is not normal in a non-syncro'ed transmission (the 3 speed in my 59 never did it). Like Jerry points out, there is some minor clutch drag. Is the grind significant? If your transmission shifts smooth with the engine off, I'd discount a tranny issue.

My bet is that you have a problem with the disc and heat makes it worse. You may get some relief with the second to first technique but if this is a change from how it used to be, I would change the disc.

Drive it a few miles, and do a lot of stopping and starting, using my 2nd. to 1st. shifting technique. If it doesn't improve in 100 stops or so, tinker with the clutch adjustment and/or pull the clutch disc and see if maybe the center hub is bent. I've seen clutches get bent and wobbly by letting the weight of the transmission hang on the input shaft while installing it.
Jerry

Should have read your post a little more closely, I didn't catch the "Stopped" part. Do as Jerry suggested and if it doesn't smooth out readjust the clutch. Hey, we all live and learn together.

Jerry's suggestion is common practice as far as I know with any 3 speed non syncro first gear transmission. I rebuild a lot of the SM318/SM319 transmissions and most of them have chipped teeth on the L/R slider and the corresponding gear on the cluster. If you force it into first it will eventually cause serious damage.
Those gears are becoming harder to find and are pricy as well.
Clutch issues aside, it's an easy practice to get into.
Fred

Grinding first gear was a common problem back in the 50's. You should have a little more separation than 1/8" Grinding the gears isn't particularly good for them, but if you pull it almost into 1st gear and give the driven gear a little time to slow down, that usually helps. Using 2nd to stop the gears wears the 2nd gear synchro, and the synchro assembly is getting very difficult to find and expensive. We used to put new synchro rings in the synchro unit, but I don't think anyone makes the synchro rings any more.

Did you have your flywheel machined before you installed it? Wear on the flywheel will cause a clutch that wasn't worn in with it to drag.

What is your engine idle speed? If it is above specs, it will grind.

Thanks for the help everyone!

Jerry- I will give the 2nd gear quick to 1st trick a try and report back as to how that goes. I will be away from the truck till next weekend so it will be a while before I get the chance. Hopefully that will work for the time being and the clutch will wear in as you say.

The longer I wait at a stop sign with the clutch pushed in the less grinding and the easier it is to get into first gear. The only problem with that is if I have traffic behind me they don't seem to appreciate the 30-60 seconds I sit at each stop sign. The nerve of some people!

So here is bit more info...The truck came to me with the 235 just bolted in it and the clutch and transmission installed to the engine. I hooked up the shift and clutch linkages and in doing that discovered it had the wrong throwout bearing and was able to get over that hurdle. I was told by the previous owner that he had removed a later model 350 that had used the same transmission that is currently in the truck now. So I assume that the clutch must have come with the 235 that's in the truck now unless its the same as one used with a 350. He told me he inspected the clutch and it all looked "like new" so he reused it. So I have no clue what shape "like new" to him is. But I would think that the clutch and flywheel must be worn together in their previous life before it made its way to my truck. To my knowledge the flywheel was not resurfaced. I feel like the clutch is working fine in my opinion. It seems to grab great and feels solid. But I am the guy that hooked up the linkages and I don't profess to be a mechanic so it's very possible I'm goofing something up. I've been learning as I go....or don't go..as is the case now.

So I have a couple more questions for you smart guys.

1.-If the clutch has a slight drag. That should eventually wear in, correct? Could I expediate that wear in process by taking off in second gear instead of first gear? I wouldn't do this trying to go up a hill but just for a while on flat roads. My thought is the extra slow clutching necessary for getting the truck moving ought to wear it in a bit faster.

2.-If 1/8" separation between the clutch and flywheel is not enough what should it be? And how do I go about adjusting that spacing? The only spot I see where I could change that spacing would be to back out the clutch fork pivot ball/bolt. I messed with The free clutch pedal adjustment nuts on the shepards hook that links to the clutch pedal and that didn't make any difference with the grinding in first gear.

Thanks for the help guys!

There is no real spec for the distance, but 1/8 is rather small. I like to see the linkage adjusted just as close as possible without the throwout bearing running all the time. If you do encounter times you can take off in 2nd, go ahead and do it. The disc will usually get better as it it wears in.

Back when these things were new, we didn't have the traffic we have now and we are able to give them more time. I wouldn't make a habit of it, but in a tight situation, using 2nd to stop the driven gear is probably the best solution. Another way to do it if you can is to pop it into 1st while the vehicle is still moving a little bit instead of waiting until you are at a dead stop.

I have put thin washers for shims between the pressure plate and flywheel on some real bad ones.

But when it gets down to it, it has always been a problem. That is why Saginaw put synchronizers on 1st gear in 19663

Downshifting to 2nd. as you roll up to a stop and shifting back to 1st. as soon as the vehicle quits rolling will also let you get ahead of the cluster gear spinning situation that's causing the problem. Letting the clutch out in neutral, getting all the gears spun up, and then trying to shift into 1st. is what's causing the grind. If you don't spend any time in neutral, there's never an opportunity to get the cluster gear spinning.

I love automatic transmissions- - - -they're smarter than all drivers, and most mechanics!
Jerry

The 350 flywheel would not have been used on a 235 engine as they are not compatible. It's possible that the clutch may have been used with the 350 if the flywheel was drilled for the smaller pressure plate. I'm not sure what the standard for "like new" would be from someone selling something.
Fred

I am still waiting to hear what the RPM is at idle.
I have a T-5 which is synchronized in all gears, but will grind a little in first or reverse it I have the throttle cable pulled out for warming up the engine on start up. When I push the cable back in, everything shifts like butter.

Carl-I don't know what my current idle RPM is. I picked up a mini tach this week that I will put in this weekend and I'll report back.

I was able to get out in the truck this weekend. I am happy to report that the sneaky trick of shifting from second quickly into first works great! I am thrilled I can drive it now without grinding into first. I'm learning that I need to plan ahead in my driving when it comes to lower speeds. For instance I had to slow to let a pedestrian cross the street while I was going up a slight hill. I was going too slow for 2nd gear but I was still moving so I couldn't get into first without making a complete stop first which seemed to bother the traffic behind me. I'll get the hang of it after a few more trips on the road.

As far as my idle speed goes. I installed the tach and it was reading at 600 rpms. I adjusted it down to just below the 500 rpm line. The manual says 475 but the tach isn't that exact. I went for a spin and still had the grinding in first issue. So hopefully the more driving I do the problem will eventually go away as the clutch wears in.

Thank you everyone for the help!