The Stovebolt Site Forums The Shop Area Engine Shop Third gear grind but not second...RPM's?????

HI All...quick question on my 54 3100 1955/235 three speed with OD(not hooked up) and converted from column to floor with a kit. WHY is it if I hesitate and allow the rpms to come down and sneak the stick into third I can shift with NO grinding. But if I hog it into third grinding occurs??? Second gear no grinding at any speed and first... well you had better stop no syncros there. Also I drive her about 50-55 is this cool or should I make 50 top speed? THANKS, Steve :rolleyes:

Steve,
That transmission has a syncro drum which has identical internal components on each end of the drum and the method of engagement in both second and third. Having said that if one gear won't engage or stay in gear it is very likely the syncro is worn. The rings on either end wear and could cause the problem you describe. Another problem could be in your floor shifter adjustment or wear in the shift arms and/or the 2-3 shift fork internally. When you get the grinding sorted out you should get the OD hooked up and be able to do 70. All of the electrical components are available and it makes for a better driver.
Fred

Steve,

When you wait to stick it in third gear, letting the RPM's drop before you do so, you are in essence double clutching...without using the clutch. If the output gear is turning the same speed as the input gear, no grinding will occur..you have matched the gears in rotational speed. Technically, you could shift without using the clutch merely by matching the speed of the two gears. Truckers do this often.

Stuart

This brings up a good point for me to learn....how does one go about adjusting the rods on a floor conversion stick shift...or...where would one look for that kind of information. I have no idea who made this shifter maybe Daytona? THANKS,Steve

Steve,

Some conversion kits have a small hole drilled through the shifter frame AND both arms. The procedure is to align both arms with the small hole, which a small rod can be inserted into. When both arms are adjusted so you can insert the rod all the way through the frame, the neutral gate is perfect....this is what you want.

If you don't have this little helper hole, it is still real easy to adjust. You adjust only one arm...it is adjusted to the other arm until the shifter can be pulled through the neutral gate with no hang ups or glitches.

The side cover has the detents and determines where the shift arms locate. When you adjust a conversion setup, you are only adjusting the neutral gate...that's it!

Stuart

Who Me: It sounds like the synchronizer's worn out. What happens when you double clutch?

So do snowplow drivers.

THANKS.. will give the unit a look for that hole. Seems complicated with all the rods and what not.. maybe a transmission shop is in order for the first time?

I have heard about double clutching but I have no idea how to do it? THANKS, Steve

also makes a big defference on oil in the tranny i had a mucie that would grind on a few gears i drained the oil and put in 90 wt. with 10 percent stp oil treatment magic no more grind i think it made the syincros work better

Well I'm in the same boat! My 3 speed OD purchase has a bad syncro in 3rd gear. Is there a good place to buy the parts, new or used? How hard is it to replace and any special tools required?

You can get a rebuilt syncro drum from Anaheim Gear in Anaheim, CA. 1-800-477-1103. I think they are about $125 exchange. No special tools required for the replacement, refer to the shop manual for dissassembly/assembly instructions.
Fred

The old 3 speed I took out shifted OK, are the syncronizers the same? Maybe I could swap them into the OD. Havn't got all the OD parts hooked up yet maybe I should test all that before I pull the transmission in case there are more problems in that area too. I know the sol will engage so thats a start.

All of the internal components are the same if they have the 4 bolt side cover. (except for Corvette). You might want to use the clutch gear along with the syncro from the other transmission. Check the 2-3 shift fork for wear also.
Fred

The SM 318 (with or without overdrive) is relatively simpe to work on. Just really need a good manual to reference. personally, I use a 70/30 mix of Lucas synthetic 75w90 and Lucas synthetic oil stabilizer (also used as an assembly lube, nice and sticky). Shifst real nice, even without the clutch.

I had the same problem. Worn out synchro.

syncro bad...doc

Not a big job to replace the synchros, when I was young I could do a complete R & R and rebuild the trans in about an hour. Weak synchros are most likely, but possibly the snap ring retainer could be popped out, I used to do that by speed shifting and it acts just like worn synchros. Those 3 speeds are absolutely the easiest transmissions in the world to work on.

Thanks for all the insight and comments. I took the cover off the OD one, and the 3rd gear syncro just flops around on the shaft, from looking at the parts breakdown, looks like the snapring is broken or missing. So I started taking the original 3 speed apart to compare. Can you say "needle bearings"? I have a pile of them so that should be fun trying to get all those back in when I get the parts swapped around. If the snap ring is still there and in one piece, can it be reinstalled without tearing the OD tranny apart? Thanks again!!

You have to take it apart. Even if the snap ring is still in one piece, I wouldn't take a chance on it by trying to use it again. Parts are worn or it wouldn't come apart. The groove in the syncro ring could also be worn. Use the good parts from the other trans.
Fred

Ok, well we are making some progress although we had about 30 tornados here one week and now down to 14 degrees this morning so winter is back! Over the last couple of weeks I replaced the clutch/pressure plate with another new one and that solved my vibration issue. I then swapped the whole 2/3 gear clutch sleeve from my old tranny to the OD one and now it shifts real good. I got the pull cable installed, the relay mounted and wired up and the kickdown swith mounted on the carb and wired. However it now appears that the governer is not working. So the saga continues. I verified that I have 12V to the governer and then I hooked up a test light. Have the rear end on jack stands and even at 50 MPH the light doen't come on so the governer switch is not completing the ground path. I took the cover off and ran the truck, but the brass looking weights in the governer don't turn at low speed as I expected they would. Should they spin all the time, or just when its above 30 MPH?

I test them with an Ohm meter. Take the govenor out of the trans and secure it in a vise. Attach a test lead to the contact terminal and the other to ground. Put the drive end in your electric drill and spin it up. If it pegs the meter it is OK, if not it has problems. If it tests OK and not working on vehicle you have problems with other components.
Fred

It it wern't for bad luck, I'd have no luck at all! I pulled the governor and tried the drill test, it was a little flakey so I took it apart and cleaned it up. Did the drill test again and that work ok. I left the cover off so I could turn the shaft as I instaled it just to see how it engaged the drive gear. It went all the way in and never caught any thing, just a clicking sound at the very bottom. So i got a mirror and light and looked down the governor hole. The drive gear teeth are ground off at that spot! Does the speedodometer & governor use the same drive gear? My speedo works good. I guess I'll just put a toggle switch in for now and maybe someday find a part and fix it. I'm not pulling that tranny again for a while. Thanks for all your help!

The speedo and governor drive off the same gear on the output shaft, but drive off diferent parts of it. The gov. drives off the aft side of the gear, which is about twice as wide as the std. 3 speed drive gear.

You said that you don't want to take it apart again but you have to ask yourself: Where did the broken teeth go?
They have to be inside the overdrive portion of the transmission, if these broken parts get into the planetary and other moving parts in the OD it will take them out and they get real expensive.
Fred