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Hi guys, I'm new to the forum. In '98 i bought a 65 c-20 fleetside, worked on it for two years, somewhat finished at and then had to leave it until this summer because of college. Sandblasted, por-15 coated chassis 2-1/2 inch drop on the front, power steering power brakes, 3/4 stepside bed w/ tire carrier on side above running board, corvette rollpan, grey tweed 'rod-doors' door panels, matching carpet and grey tweed seats, 250 i-6, runs like a top, hoping to finish the paint and bodywork this summer. My only problem is the transmission. When shifting into third it scrapes, and you pretty much have to slow down to 10-15 mph to get it in, downshifting is also a problem from 4th to 3rd. Was just wondering if this could be a syncronizer? Any thoughts or suggestions? Also the clutch is very heavy, and despite the age I would say it is heavier than normal, is there any way I can lighten it? Thanks for the help

Matt,
I had an 11" clutch in my 68 (68 C10, 250cid with SM420). The clutch was so heavy that I was hurting my left knee in heavy traffic. I changed it down to the 10" (10.5"?) clutch plate an it's been much easier to drive ever since. If you're not doing alot of heavy hauling or drag racing, the smaller clutch plate may be a good idea. Or talk to a clutch shop about it. The may be able to put softer (weaker) springs on a reman 11" plate for you.
About the tranny, I can swap 'em out all day, but the insides are pretty much greek to me, sorry. But whatever you do, don't try to "bench press" those 4 spds in. I did 3 years ago, and I think the bruses on my chest have finally healed....

Hi -- and welcome to The Stovebolt Forum. You will find the answer to most questions, and make some friends too. (That is if your not to picky about who you make friends with.)

Your clutch is a big heavy duty 11" clutch, and I would advise against changing it. That thing can handle all the torque you will ever want to throw at it. I just slip my truck into nuetral if I have to sit in traffic.

Sounds like your tranny has a couple of synchros out. I don't think those old 4 speed are easy to come buy these days. If you can find one it may be newer and expensive. You can get a good rebuild kit for your 4 speed from JC Whitney, or pick up a Saginaw 3 speed for around a $100 bucks. A good 5 speed out of an S/10 will run around $275. If you go the 3 speed route get the one with the 2.54:1 1st gear for the best ratios. With the 5 speed the one with the 4:1 1st gear has the best overdrive 5th. ( Now be careful cause some of the guys on this board will try to convince you to go to a 700r4 automatic and 308 gears Don't do it. It's downright sinful.) Good Luck, and keep us posted on your progress.
Bob

The 3rd gear synchro on my 64 SM-420 is a little weak. But then I remember back when those were new trannies and they were never made for speed-shifting. I learned how to double-clutch on the 420 and whatever its crashbox predecessor was. I drove ice cream trucks when I was a teenager and they were invariably Advanced Design chevys or Jimmys. They all had 4-speed crashbox transmissions and required a double-clutch technique to get from gear to gear without removing the teeth.

I got so that I could do it without the clutch. You find lots of things to do when you're bored out of your skull listening to that silly-arsed ice cream music for 10-14 hours a day.

But the lessons were invaulable. I still double-clutch up into 4th and down into 3rd...just cuz the 420 seems to be happier that way. And yeah, the clutch is heavy as hell.

More "I remember" stuff. When I was in high school, I took autobody classes in the summertime. Some guy brought in a brand new Chevy truck (must have been around 62 or so) that had a ding in the fender. He had all of us try to press the clutch pedal down. There were only a few kids who could do it. I depressed it..but only by using both legs. It was one of the stiffest clutch pedals I think I've ever seen.

If you're having trouble releasing the clutch all the way, you're probably overriding the synchronizers when shifting. the clutch must be fully released before the trans will shift smoothly. Figure out the clutch problems first, and the shifting will probably take care of itself, unless the synchronizers have been worn out by years of shifting with a draggy clutch. Look for tight spots in the linkage, or wear that's preventing the throwout fork from moving to the full-disengaged position.
Jerry

I agree with Hot Rod. Your clutch isn't releasing all the way. Does the pedal have freeplay or the lack of? It may have rust on the throw-out/inputshaft housing. I've seen the damper springs come out of the disc and lodge between the disc and pressure plate on other brands. This will keep the clutch from fully disengaging.
Food for thought,
Scott

I've seen the damper springs come out of the disc and lodge between the disc and pressure plate

That sounds awful!