The Stovebolt Site Forums The Shop Area General Truck Talk 2nd Gear Blues

OK... I have a problem here I'm hoping people can shed a light on for me. (54 Chevy 3100, 235 engine, standard transmission)

The gear shifter gizmo on the top of the steering column (inside the cab) had worn, and the gearshift was jumping all around. I found a way to fix that (more on that in a minute). Once I did, I realigned the entire shifting linkage. Tried to do it to specs, however with everything meeting specs I couldn't adequately shift into 2nd and 3rd gears 'cuz the shift lever was pointing too high. So I moved the gear shifter box (clamped to the steering column behind the firewall) around until the shift lever was perpendicular to the dash, and realigned everything again, replaced worn bushings, etc.

Now when I drive, 2nd gear does not engage properly, clatters, tries to jump out of gear, and when I depress the clutch I can feel something like the edge of the teeth missing their contact, about midway through the pedal movement.

I tried adjusting the clutch pedal travel thinking that maybe there wasn't enough contact being allowed for some reason. That didn't help.

This all started with the shifter housing thing. Coincidence? Or is something still out of alignment? I had the engine and the transmission rebuilt between 2000 and 2002, and in the 9.5 years I've owned this truck I have never had this problem come up. Anybody have any suggestions as to what's going on and how to remedy it?

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Oh, and as for the upper gearshift housing repair, I found that removing the whole gearshift arm and wrapping the threaded section with about 5 windings of teflon tape, then threading the housing back on seems to have done the trick. I found remnants of old teflon tape in the threads from a previous repair of mine which must have been done when I had the engine out for rebuilding... lasted about 7 years before needing to be redone.

I should add that the other gears are working fine. It's only the second gear that is acting quirky.

mandrew,

The detents on the shift levers inside the side cover dictate where the forks position themselves, and everything else is adjusted to them . As you have probably discovered, the shift box on the steering column will flop all over if given a chance.

If you put both levers on the transmission in the middle detent, that should be neutral. Attach the 1st & REV lever to the proper arm on the transmission and shift box. The shifter inside the cab should be in the approximate 3 o'clock position (I think).

Attach the 2nd & HI lever to the transmission arm and shift box. If you can sit in the cab and pull the shift lever toward you through the neutral gate without any hitches or git-alongs, this is perfect. If the gate needs to be adjusted, remove the last rod you attached...the 2nd & HI rod, and adjust it with its threaded adjustment, or little locking slider adjustment until the neutral gate is flawless.

What do the instructions in the manual say for positioning the shifter in the cab...2:30 or 3:00 o'clock! This makes sure the arms in the shifter box have adequate travel in both directions and don't crash into the box and prevent the transmission from fully engaging a gear...sort of like what yours is doing. Give it a go and let us know how it worked.

Make sure any nylon bushings, if there are any, are new and tight.

Stuart

Hi Stuart,

Thanks for your detailed reply. From what I've experienced, the order you have for attaching the shifting rods is reversed, as gears 2 & 3 (high) are the "default" settings at the gate, and the lower gate is what controls both the higher gear shifting and the position of the shifter lever in the cab. Be that as it may, I have tried loosening the rods and moving the 2-3 gear rod into its 2nd gear detent and then tightening the clamp on it. That hasn't seemed to help. The rod/tranny side lever doesn't seem to lock in any deeper as a result.

Bushings are all new (rubber), The manual says in neutral the gearshift lever should be horizontal, which would seem to indicate the 3:00 position. That alignment is fine, and the gates as I have them set are working without interference. Where I ran into trouble with the specs was the distance between the bottom of the steering wheel and the top of the gearshift lever. Specs call for it to be 2-13/16" +/- 1/8". Set to match those specs, the gearshift lever was not perpendicular to the steering wheel as it should be, but rather pointed upward making the operation of the shifting gates impossible. I moved the gear box up the steering wheel shaft until the lever was perpendicular and the shifting mechanism had equal amounts of movement in all directions.

It is possible that there's a misadjustment at the point where the upper and lower control rods are clamped together, however they seated nicely when I put that assembly back together. That could account for the inability to align the steering wheel-to-shift lever to specs, I suppose. However I am not sure that a misadjustment there would result in my losing 2nd gear.

For what it's worth, the R-1 gear detent is a little flimsy in gear 1, making the adjustment of that rod trickier. What I mean by that is that when shifting from 1 into neutral, there seems to be a little play in the detent; it doesn't snap into neutral, although a slight upward movement of the lever seats it properly. Until I made my recent ajustments I was having a problem with the gear box jamming between 1st and 2nd due to this softness in the detent. Now it shifts fine, except for the improper seating of gear 2.

Do you suppose this could all have to do with weak springs in the transmission side cover? Or perhaps some dirt/crud buildup in the tranny?

mandrew,

Whew...you have been around the block on this thing! I'm not sure I understand all I read, but it sounds like you know what you are doing. The detent springs could be broken, but I am doubtful about dirt or crud holding anything from meshing. The spinning gears and washing action of the gear lube usually keep the moving parts clean.

The only spring in the shift box should be the one that holds the lever 'down', or on the 2nd/HI shift arm. To engage 1st/REV, you have to pull 'up' through the gate. Is this right.

If the shifter box is dumb, and the positioning of all linkage components is achieved with detents in the transmission sidecover, isn't this what everything has to be 'zeroed' to.

With the shift rods off, can you move 2nd/HI lever to a crisp, positive detent where 2nd would be. Unless the fork is badly worn and not shoving the synchronizer far enough engaged, the detent would be the correct position.

Broken, loose or oil weakened motor mounts will allow the motor to torque and play strange games with the shift linkage. I'm reaching for straws, but I would take the truck out in front of the house, drive it until you were in 2nd gear. Shut it down and without moving anything, pull the shift rod for 2nd off the transmission shift arm and see if that shift arm was seated in the detent.

We might not be on the same page on the problem. Keep us posted.

Stuart

Another little trick that helps is to shim all your linkage ends with thin washers until there's no slop in them,but they still pivot freely. A little wheel bearing grease on 'em isn'r a bad idea either.
Speed

<blockquote>"The only spring in the shift box should be the one that holds the lever 'down', or on the 2nd/HI shift arm. To engage 1st/REV, you have to pull 'up' through the gate. Is this right."</blockquote>

Yep, absolutely right.

I do have to say that whoever designed the linkage on these things really found a way to overcomplicate the concept. The more parts that have to be aligned, the more margins of error exist. I like the novelty of the three on the tree, but man... a floor shifter seems like it would be far more practical.

<blockquote>"The detent springs could be broken, but I am doubtful about dirt or crud holding anything from meshing. The spinning gears and washing action of the gear lube usually keep the moving parts clean."</blockquote>

It's been a while since I looked at the inside of the side cover of the transmission case, but as I recall the detent works via a spring/ball mechanism that sits between the shifting forks and the housing. The shop manual shows these parts, albeit removed and laid out. I believe the ball at the end of the spring has to seat into a small indentation for the detent to work properly. Since these parts are on the vertical side cover, I wouldn't think they are necessarily in the direct path of the swirling oil bath that washes the gears and synchros. So it was my guess that a buildup of sludge from old gear oil could concievably get packed in the little indentations, making the detent less effective.

I could be wrong, but if that were the case it would help explain the sloppiness of the 1-R gear detent and possibly even gear 2's poor behavior all of a sudden.

Speed's recommendation of adding washers is yet another "fix" I have planned for the linkage. I noticed a little more play in the 2-3 linkage than I would like, and in 1-R, the linkage is definitely tighter. There's also wiggle room in the 2-piece pivoting mechanism that attaches the upper rod sections to the lower ones, but there's not enough space to squeeze another washer in there. So I may have to live with wobbliness in that mechanism. The original post that protruded out from the bell housing was replaced by a previous owner with a section of a bolt which for all intents and purposes may be a hair smaller in diameter than the original post, and that could account for the extra play there.

Well, I guess the best answer is to take the side cover off when I have the time to devote to that, and see what shape the forks and detents are in... and poke around in the gear assembly to see if there's some other reason that 2nd gear is not mating properly. But if anyone has any other ideas, please go ahead and post them. Since the truck is my daily driver, I'm hoping this problem can be solved without a full tranny rebuild!

Thanks for your input guys. Most helpful!

Here's a new twist... 2nd gear doesn't seem to be sliding on the main shaft as it should. Now, not only does it try to pop out of gear, but when I try to shift from 2nd to 3rd, it isn't getting out of the way so it is making it difficult to shift into the gear. Hmmm. And I hope it's my imagination, but it seems as though 3rd is getting a little noisy. Now I'm wondering if perhaps the rear bearing has slipped out of position somewhat.

I haven't had a chance to pull off the side cover of the transmission yet, and it's supposed to rain tomorrow so it looks like it'll be a couple more days of driving in 1st and 3rd only.

Is there a doctor in the house?

mandrew,


It isn't suppose to rain in southern California!

Those transmissions are quite simple to take apart and reassemble...even easier with a shop manual and advice from the old coots on the Stovebolt.

Stuart

yes they are very easy to rebuild. i rebuilt the 4 speed in my 49, with just a diagram or what went were. i had never done it before and once the trans was out of the truck, i think it took about an hour to overhaul.

If you loosen the nuts on the shift rods at the box on the colum and shift the transmissio manually you shold be able to find out if its lincage or tranny by driveing in each gear,stopand block wheels,shift into next gear by hand,ect...I suffered a simalar fate for some time.Mine was a bent shift rod.

Well, I think I can rule out the linkage as the problem. I've been over that with a fine tooth comb, disconnected all the rods, put new washers in, tightened the whole shebang, and played with the transmission levers on the side cover as I was reconnecting the rods. There's no more or less play involved whether the rods are on or off. Looks like something's not moving properly inside the tranny, and that's why 2nd isn't locking in place properly and jamming when I try to shift into 3rd.

It's been interesting driving in LA with only 2 gears...

At least the linkage is now tighter than it's been in a decade! There's no excess play in the whole system, and once I get the problem in the tranny fixed, I'll probably have the snoothest running '54 on the block.
... even if it's the ONLY '54 on the block!

Tomorrow I think I'll pull off the side cover and see what's cooking in there. And yes, Stuart, it DOES rain in Southern California. Mostly when it's time to fix something on the truck!

Good news, Bad news...

Well, I found the source of the problem. The 2-3 gear shifter fork inside the side cover of the transmission is seriously worn. There was a lot of powderized metal from the thing that had got stuck in the nooks and crannies of the side cover. I cleaned it all out and put the thing back together, but 2nd gear is still bad.

Now the challenge is to find a replacement part. I usually rely on NAPA for hard-to-get parts for my truck, but they don't carry anything for the GM transmission.

Anyone have any suggestions?

UPDATE: 5-5-07

Well, I finally got a new 2-3 shifter fork (what a beauty it is!) and installed it. 2nd gear is only moderately better, but it still tries to kick out and catches when I go to shift into 3rd. Something's not meshing right, and when that happens I hear a clattering of gear teeth as if they're not quite lining up :-(

If I step on the clutch again when the gear jams, it frees up and I can shift easily into 3rd.

I wish I knew more about the inner mechanics of the tranny so I'd be better able to pinpoint the problem. Gears R, 1, and 3 work absolutely fine. And given the limited range of gear movement allowed by the shifter forks, I'm inclined to believe the problem lies somewhere in the clutch-to-2nd-gear lineup. So today I think I'm going to play with the clutch pedal travel and see if that has any effect.

Anyone have any other suggestions?

The clutch adjustment will have no direct bearing on second gear if you can select all other gears. Does the transmission engage the second gear shift detents when the linkage is either connected or disconnected? Maybe some of the powder you found was from a lunched thrust washer that moved things so that the gears no longer line up.

Hi Baldy,

Yes, the second gear detent seems to lock in fine whether connected or disconnected. So I don't think it has anything to do with the linkage being too short (if that's where you were going).

It's possible that the fine metal shavings were in part from a thrust washer (I was beginning to wonder about that washer and the role it plays in the gear shifting), however the old 2-3 gear shifter fork was ground down a good 16th of an inch which is why I assumed the residue was from that.

So tell me about this thrust washer. What exactly does it do?

Oh, and thanks to stovebolter ave Razey I now have another gear shifting box to play with. I'm gonna clean that sucker up and see if it will be any tighter than the one I've had in there for the last 7 years.

The existing one leaks grease out of the back end like a sonofa... and it seems like there's a tad too much of a gap between the shifting gates.

Thanks Dave!!!

One other question, Baldy... if the clutch won't have any direct bearing on second gear, why is it that a quick stepping on the clutch when the gear is misaligned causes it to free up?

The lack of something, possibly a thrust washer, is causing the excessive gap between the gears that you mentioned. One scenario would be that hitting the clutch a second time causes backlash of the gears and the second gear is moved into a better position. Clutch adjustment can have nothing to do with anything inside the transmission, as the only thing the clutch touches is the input shaft.