SM465 shifting question

[Gregsenne]

I have a 86 K20 with a 79 SM465.

I'm having problems with getting into first gear. (When I say first, my shift knob says L-1-2-3-R) And I know its a common problem with these transmissions, but there has to be something I can do....

At a complete stop, I can get into granny easier than first, so I sometimes find myself shifting to granny for a split second, then to first. I can always get into first if I play with the clutch enough. But sometimes, it's just faster to do granny, then to first at about 3 mph.

Unless I shift from granny to first, I cannot get into first gear unless completely stopped. Let's say I'm coming to a stop light and the light turns green when I'm almost stopped. I either have to put it in 2nd and rev the engine/ride the clutch until it's to speed, or come to a complete stop, and then put it in first. Same happens when going around a turn. I usually turn onto a road, and stop completely, then take back off. Major pain in the butt.

I know my gears are too tall, I'm working on changing that. It has 3.73 gears with 35" tires.

I took the entire trans apart before I installed it and inspected everything, everything looked good. I just broke a pressure plate finger, so I'm about to take the trans out again. If there's something I need to do inside the trans, now would be the perfect time!

Thanks for the help.

Greg

[INSIDIOUS '86]

Have you tried putting it in another gear and then into first? Like 2nd or 3rd just to move the gears around then to first. I don't think first has a sincro ring on it in these trucks so the gear mesh is not as great. Not sure if the gears have beveled edges but a 30* combined angle helps them match up a lil better.
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[86c20]

first is sycro. low is not. mine does the same thing. they all do i have 3. the one in my wrecker is so worn out tho that 99 out of a 100 you can shift in to low with no grinding. big thing is to match the rpm to the gear. if you rev it up just a bit it will shift right in no problem. have to do it on my k30 and my c20 and the c20 has less then 50k on a new trans.

[cory d]

i would think that 1st wuld have a synchro? i down shift into first for corners all the time. getting into L or R i sometimes shift it into gear as i push teh clutch in.

[KQQL IT]

L and R in 465's are not synchronized. Go into 1-2-3 before L or R should ease you pain.
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[Gregsenne]

Going into L before 1 makes going into 1st easier. To me, it seems odd that since L is not syncronized but 1 is, why is L easier to get into? Honestly my 3.73 gear and 35" tires makes me need to ride the clutch just a bit even starting in 1st gear. If I have to take off up hill, I always start in L.

Rev matching doesn't seem to help much getting it into 1st at low speeds. But then again maybe I just need more practice.

I guess my question would be... I gotta pull the trans to fix my pressure plate. So while i got it on the floor, I'll fix whatever i need to inside the trans. Would a new synchro on 1st help?

[83GMCK2500]

I have never seen an SM-465 knob say L-1-2-3-4-R...mine says L-1-2-3-R.

I have ~500,000 miles on my SM-465 and both L (1st) and 1 (2nd) can be finicky to grab from a stop. With a slight roll or partial double-clutch I can grab either just fine. Sometimes kicking it over to 3 (4th) helps with getting it into 1 (2nd).

I haven't found one that I can't RPM match and float through the gears on yet.

[Gregsenne]

Ok when I drive it later ill try double clutching it and Ill try rev matching. Maybe I've just been spoiled with all these new transmissions.

And my shifter knob says L-1-2-3-R. There's no 4 on my knob. I only mentioned it because some people refer to them as L123R and some 1234R.

[Desert1957]

"I just broke a pressure plate finger, so I'm about to take the trans out again."


I'm totally confused by your statement in your first post. You have a clutch issue and you are wondering why your trans is hard going into gear??????


HUH?

[Gregsenne]

The clutch issue is one broken finger on the pressure plate. It makes a loud clicking noise. But it doesn't affect the ability of the clutch plate to engage or disengage.
So I'm not seeing how my pressure plate issue is any bit related to the trans being hard to get in gear at low speeds.

After doing some research I really think its just my driving habits that are causing my problems. I daily drive a car with a 5 speed, so I guess I'm just used to the smoother shifting, and being able to get into any gear easily.

[Desert1957]

Originally Posted by Gregsenne

The clutch issue is one broken finger on the pressure plate. It makes a loud clicking noise. But it doesn't affect the ability of the clutch plate to engage or disengage.
So I'm not seeing how my pressure plate issue is any bit related to the trans being hard to get in gear at low speeds.

After doing some research I really think its just my driving habits that are causing my problems. I daily drive a car with a 5 speed, so I guess I'm just used to the smoother shifting, and being able to get into any gear easily.

You did not specify which style clutch plate you have. If you broke a finger on a "Long Style" plate it won't work.

If you broke a finger on a "Diaphragm Style" it probably will not effect your shifting.

Here are the differences...

Long style


Diaphram style


Desert

[Gregsenne]

It's the diaphragm style.