SM465 shifting rough

[diesel4me]

I have driven a few old trucks that had rotted cab mounts,you could feel the cab lift up when you pushed the clutch in !...the cab moving around as well as flex in the frame when crawling over obstacles can make the linkage come off or fail,though it dont happen often,it can become a hazard when your in a dicey situation and need 100% control..

I had one linkage come off a '72 GMC I was plowing with,when I was pushing the snow as far up the pile as possible once...I pushed in the clutch,felt something "give",then the darn truck kept right on going, until I shut the key off--by then I was high centered on top of the snowbank,took me half an hour to shovel it out of there...

Maybe my man card needs to be turned in,I like my TH400 a lot better than a SM 465 when plowing,or just overall driving...I never liked the gear spacing and having to shift & clutch constantly in heavy traffic around here..a clutch dont live long in stop and go traffic....it'd be ok if I lived in the midwest where your in 4th 90% of the time...

I dont worship automatics either though,once they act up I always wished I had a manual instead...if GM had a decent 5 or 6 speed in the old trucks that didn't shift like a dump truck or have big gaps between gears I'd probably want one over an automatic...the hydraulic clutch does reduce pedal effort a great deal and makes one less tiring to drive,so I'd want one over mechanical linkage too if possible...(despite the fact they can be a PITA to bleed and leaky sometimes)..

 

[82355]

If you know how to do it, they are simple to bleed. Ask Ryoken.

Martin

 

[yakmastermax]

So I jacked up the truck really high because I've definitely got some plans for it

While it is up there I thought it prudent to hold off on the big plans though and address the current problem.

I pulled all of the drive line piece by piece (rear drive shaft, t-case, cross member, transmission, bell housing) after attempting and failing to use the harbor freight 450lbs tranny jack to lift then lower the transmission mated to the adapter and the t-case along with crossmember.

I thought it would be slickest to just unbolt the tranny from the bellhousing (4 bolts) and unbolt the cross-member from the frame (4 bolts) and drop the entire thing in one smooth move but the "450lbs" tranny jack decided to basically fall apart.

The last bit of use the "jack" got was toppling over because of its bent frame, safely delivering the SM465 to ground level where I could untangle it from the blocks of wood and the "jack" to drag it out from under the truck.

Other than the transmission jack being utter junk the day went smooth and I think I've got some solid data points from which I'd like to extrapolate a solid understanding of just what went wrong!

Pictures:

When the transmission first came off this is what I saw:







I'm not sure what to call it but as you can see the spring which retains the clutch fork to the pivot ball is broken. The case for the throw-out is cracked on one side and deformed on the other.

Not pictured but was visible to me once I removed the bell-housing and clutch fork was the state of the pressure plate.

Without the bell-housing on and with only the pressure plate bolts holding it to the flywheel, the fingers of the pressure plate were not exactly right.

I forgot the exact orientation but 2 of the three fingers were "out" while one of the fingers was stuck in the "pushed in" position. As I unbolted the pressure plate from the flywheel all three fingers returned to the same position.

Not pictured either is the flywheel; it has streaks and blotches and generally looks like it got some heat.

As it stands I've not idea what exactly went wrong so I'm keenly open for ideas and input.

These parts pictured were all put in by yours truly last summer, almost exactly 11 months ago.

Whatever I do next I want to do perfectly and not have this happen again!

I've already priced out two replacement diaphragm clutches sets from Oreilly's (they're gonna warranty the one in there!), a new flywheel, a new clutch fork and new pivot ball.

The 12" diaphragm clutch is $150 and the 11" diaphragm is $50 and listed as "HD, heavy duty"

Since I'm getting a new flywheel I'm wondering if the 11" is the way to go to save some coin.

Also what other things should I add to the shopping list

As always, thanks guys for your expertise and input. I've got big plans for the truck and this is just the first step. Next few days I'll be removing the axles.

 

[82355]

You won't need a new flywheels, they can just turn yours.

Martin

 

[chulisohombre]

Martins right. I took mine to napa and cost me 40 bucks to turn it. As long as you have enough meat on it you can do it and save some cash.

 

[yakmastermax]

I'll definitely consider that. Any idea what went wrong with the last clutch? I don't want to have to do this again. Also any suggestions on the 12" vs 11", 150$ vs 50$?

Thanks!

 

[chulisohombre]

Looks from pics that the clutch fork slipped off the throw out bearing or the throw out fell apart. As it was from pics it was only hitting 1/3 of the clutch to disengage it. Could be the clutch fork was Worn out and wasn't catching the throw out good enough. I went 12 inch as it has more grabbing marerial and I figured as with everything Else every inch counts. I figure it will take Longer to wear Out and slip less as well. I got a luk hd one from napa and its been in for 8 years now. No problems.

 

[80' 427]

12" behind my big block. No problems even when I have to slip the clutch crawling.