manual transmission

[michaely31]

Driving my new 1972 GMC

I have a few old cars but I dont remember the GMC transmission being so finicky to get the into gear without double clutching- must be part of the pleasure

Is there anything I can add mechanically to shift easier- especially first and second gear?

thanks

-Michael

[Wrenchbender Ret]

You don't say what trans you have but a 4 speed has a real low 1 st. gear that is not syncro. The rest of the gears & all 3 foreward gears on the 3 speed are syncronized. If it is hard to shift to these gears your clutch may be dragging or the syncros are shot.

[1972RedNeck]

I shift all my manuals without the clutch. The SM465 (which is what your truck should have had originally) just likes to be shifted slow and not be forced. Once you get everything spinning the right speed, it will almost pull itself into gear.

Mine is a bear to get into second if I use the clutch.

[Ugly71C20]

If its the sm465 then the shifter is probably pretty sloppy which makes things even harder. There are a couple easy fixes for the slop but they all kind of turn into a regular maintenance thing. Check this out http://www.pirate4x4.com/tech/billavista/sm465/

[michaely31]

thanks guys- will share with my mechanic also

4 speed.....
while 5 speed if R is for racing?

[Ugly71C20]

Are you using 1st? For normal driving you shouldnt use 1st or low, its 6.55:1. The SM465 is really just a 3 speed with a granny low. Start in the back left gear, get the shifter closest to the drivers seat

[57taskforce]

Originally Posted by Ugly71C20

Are you using 1st? For normal driving you shouldnt use 1st or low, its 6.55:1. The SM465 is really just a 3 speed with a granny low. Start in the back left gear, get the shifter closest to the drivers seat

That would be first gear. All the way up is low. At least the 465s I've driven all have 0n the shifter L-1 2-3 r with L and 2 being at the top of each gate and r being all the way right and down.
Not trying to be a no it all but just saying how the shifters on the trucks I've driven read. Also the 465 shouldn't require double clutching.(I drive tractor trailers so my definition of double clutching may be different than yours) They are synchronized as said above except for L. I too don't normally use the clutch when driving the 465. If your having trouble I'd bet your syncros are gone.

[michaely31]

yes, not double clutching- sounds like syncros
and will be gentle with engaging as suggested

thanks

[Ugly71C20]

Originally Posted by 57taskforce

That would be first gear. All the way up is low. At least the 465s I've driven all have 0n the shifter L-1 2-3 r with L and 2 being at the top of each gate and r being all the way right and down.
Not trying to be a no it all but just saying how the shifters on the trucks I've driven read. Also the 465 shouldn't require double clutching.(I drive tractor trailers so my definition of double clutching may be different than yours) They are synchronized as said above except for L. I too don't normally use the clutch when driving the 465. If your having trouble I'd bet your syncros are gone.

I am not sure I have ever seen an older one that still has the shift pattern on it. Around here the plastic gets chalky and and the pattern fades away except reverse. I drove a 90's dump truck with a 465 in it labeled as 1-2 3-4 R. I had a 2003 gmc 2500hd with a nv4500 in labeled 1st not low too, GM must have thought it was too confusing at some point and switched it up?

When people talk about both the 465 and 4500 it can get confusing depending on what they know about the tranny

[57taskforce]

Originally Posted by Ugly71C20

I am not sure I have ever seen an older one that still has the shift pattern on it. Around here the plastic gets chalky and and the pattern fades away except reverse. I drove a 90's dump truck with a 465 in it labeled as 1-2 3-4 R. I had a 2003 gmc 2500hd with a nv4500 in labeled 1st not low too, GM must have thought it was too confusing at some point and switched it up?

When people talk about both the 465 and 4500 it can get confusing depending on what they know about the tranny

I agree. I wouldn't even doubt it one bit if they made shifter nobs for the same year 465 that said 1-2 3-4 R. The ones I've driven have been mid 80s and lower and I only recall seeing What I originally posted but the general has been known to change things like this even from plant to plant. Like I said I've only seen what I posted but surely what I've seen is way less than .1 percent of the trucks made with the 465.

[michaely31]

its the syncro

[Don Quixote]

Normally I also don't use the clutch when shifting my 465 and I only use 1st when I am pulling a trailer and even then it is just to get her moving without burning up the clutch. I don't even use it with a load in the back. As far as I am concerned, this gear box has never been known for quick shifting as the ratios are spread really far apart and were commonly used in medium duites with 2 speed axles. I have wanted to install a ranger overdrive just to have a gear between third and forth but it's just not worth the money involved. I just take my time with the shifts and they are very smooth even with no clutch.

With all that in mind, I didn't open mine for the the first time until 2 years ago at 452,000 miles and only needed bearings. For me, that places it in the bulletproof catagory.