possible clutch problem?

[straight6chevyguy]

I have a few things with my truck that are bugging me just a bit and hoping someone can help shed some light.

My truck: 1998 c1500 4.3 v6 5speed manual 2wd regular cab Lb.

List of "Bugs" in the truck:

Truck Sometimes likes to jerk bad when shifting gears. (sometimes does sometimes does not.)
When disengaging the clutch under load I will hear a "clunk" come from somewhere outside the truck. (normally when backing or shifting from 1st to 2nd and not really noticeable at road speeds)
The clutch seems to be a bit "grabby",sort of like you slowly let out the pedal and it barely starts to engage and then wham it's fully engaged.
It just seems to Me that it should be much smoother engaging.

Not really sure if I have a major problem or not as the symptoms do Not seem to be getting badly worse.(And I drive the truck at least ones a week)

Any advice or input would be gratefully appreciated!

[speedygonzales]

Put the rear wheels off the ground and put the tranny in neutral with the parking brake off. Turn the drive shaft by hand one direction and then back the other. See if there is a lot of play and if so, where the play is. This could be the source of your "clunk".

As for the fast take up of the clutch, that could be the clutch material. Kevlar and others are known to do what you describe. If you aren't the installer of the clutch there isn't much you can do. If you are, research the clutch material and see if it is.

[straight6chevyguy]

I will check out the things you mentioned but as for the clutch it's the one that came in the truck when I got it.

Thank you for your response.

[straight6chevyguy]

Something else I also forgot to mention before is when the clutch is disengaged I here a whirring sound, not real loud but noticeable.
Not sure if it's normal or not as I have not driven many manual tranny trucks and I believe my 65 chevy makes a similar noise.

[oliver63]

that is most likely a bad throw out bearing...

Originally Posted by straight6chevyguy

Something else I also forgot to mention before is when the clutch is disengaged I here a whirring sound, not real loud but noticeable.
Not sure if it's normal or not as I have not driven many manual tranny trucks and I believe my 65 chevy makes a similar noise.

[straight6chevyguy]

Originally Posted by oliver63

that is most likely a bad throw out bearing...

Anybody know if a bad throw out bearing would cause the clutch to act funny like how I described?

[Mr_Rich]

I've had bad TO bearings on my old '73 way back when that made whirring and clunky noises. What no one has mentioned is the pilot bearing. On my '98 Firebird w/hyd clutch linkage the trans and TO bearing were good at 125K but the (roller) pilot bearing disintegrated and made shifting difficult. I think a teardown is probably in your future. Those are relatively inexpensive parts to replace with expensive labor unless you can do it yourself.

[straight6chevyguy]

I will probably have to pull it all apart sometime and have a look I guess.
I'm just a little scared of what I might find lol.

Thank you guys for the help. I will keep you posted on whatever ends up happening.

And if anybody else has any input, please comment!

[1976gmc20]

Originally Posted by straight6chevyguy

I will probably have to pull it all apart sometime and have a look I guess.
I'm just a little scared of what I might find lol.

Thank you guys for the help. I will keep you posted on whatever ends up happening.

And if anybody else has any input, please comment!

Well, if you keep driving it with a bad TO bearing you may ruin the fork and the pressure plate (ask me how I know this ).

Once you get the transmission out, you will want to look at all the parts in there and replace anything suspect: clutch disc for sure and maybe the pressure plate, in addition to the TO bearing (pretty much certainly your problem if you get noise when you push the clutch pedal down).

Anyway, you probably have a one piece bell housing and transmission which sucks because on the older trucks you could just slide back the transmission far enough to remove/replace the bearing on the input shaft. I did that on my old C-50; I just cut a big block of wood from a log to support the transmission at about its normal height, and did all the work through the opening with the dust cover removed (actually it was long gone ).

Just be glad you have a 2wd so you don't have to pull the transfer case

[straight6chevyguy]

Just wanted to mention that the truck currently has 139,598 miles on it.
I have no idea if the clutch has ever been replaced or not. I have only had the truck for a little over a year.

[Mr_Rich]

I still suspect the pilot bushing in this case. When the PB disintegrated on my Firebird I was surprised it didn't cause more "wobble" on the pilot shaft of my T56 in the car. I thought I had a trans problem at the time. I replaced the engine and trans as a retirement project eight years ago.

[straight6chevyguy]

Well after hearing you guys and I talked with my Dad I'm going ahead and tearing it apart.
Actually I just came in from working under the truck! I have the drive line out but still working on pulling the tranny.
I'm gonna have to do a web search and figure out how to remove the hydraulic line from the slave cylinder.
My silly repair book says I will need a special tool but of course it does not say what the special tool is,what it looks like,how to use it or any of that.

I have a video that I will try to load up here of me moving the truck around.
Just so you all can here the noises and clunks for yourselves.

[straight6chevyguy]

Well I watched some youtube vids and was able to get the line disconnected.

Now my problem is I can not get the tranny separated from the engine!

It Never ends!

[Mr_Rich]

Guide pins are probably corroded into the bell housing. Get some extra long M10 bolts to use as guides for install/ removal. This probably means this is the original part and has never been replaced. Get a soft-headed dead blow hammer and start whalin' on it. Should be enough. I had the same situation on my FB that I previously mentioned.

[Mr_Rich]

Oh yeah; you might need 3/8-16 longer bolts than the M10's I cited prev.

[straight6chevyguy]

Finally got it off and out from under the truck!
A big long pipe and a heavy sledge hammer was My last resort and it worked! LOL
I'm sure its not really I good idea to do this regularly because a person could bend the bell housing but I was getting pretty fed up lol. (It was stuck bad)

And yes the guide pins were pretty rusty looking so I'm sure they where what was hanging me up.

[straight6chevyguy]

So as for the clutch system...
The throw out bearing is still intact but noisy. (I'm sure it would have lasted a bit longer but it was for sure going bad.)
Clutch disc looks ok but I'm no expert on these things (This is the first time for me to work on a clutch)
pressure plate looks good.
I'm not to sure about the pilot bearing (or bushing) I'm not sure if I have a bushing or bearing, I think its a bushing, but after all the work taking the tranny out I was tired of being under the truck twisting my neck so I did not look to closely at it.(today or tomorrow I will have to take a closer look)

I will try to get some pictures taken of the clutch disc and whatever else that may be worth showing today and have them up here tomorrow.
I will try to get that video up here too.

[straight6chevyguy]

Another thing, My input shaft bearing on the tranny has a little play in it,
How much play (if any) is acceptable?

[1976gmc20]

Can't help you on the input shaft, but typically one would always replace the clutch disc after doing that much work to get it apart because they are not that expensive. (assuming you already pulled the pressure plate from the flywheel?)

I must admit that one time I did replace just the TO bearing. It was a separate transmission/bell housing and I just slipped the transmission back far enough to get the bearing off/on the input shaft. Never messed with the pressure plate or touched the pedal while it was apart so everything went back together without any alignment problems.

[straight6chevyguy]

I'm going to be replacing the entire clutch system accept the slave cylinder/master cylinder.

[Mr_Rich]

I strongly advise replacing the pilot bearing. I think they went to a bearing instead of a bushing sometime in the '80's. There's an attachment that goes on a slide hammer that makes the job very easy to pull in right out of the end of the crank. A bit of a wobble in the pilot shaft is okay. The pilot bearing is what supports the end of the shaft once it's all together. Get the longer bolts to use as guides like I recommended; it will make seating the trans to the block so much easier.

[Mr_Rich]

Originally Posted by straight6chevyguy

I'm going to be replacing the entire clutch system accept the slave cylinder/master cylinder.

Just a flush with fresh fluid should be okay. A remote bleeder from Speedway Motors can be a benefit also.

[straight6chevyguy]

Here is that video.
I'ts a bit hard to hear but at the beginning you can hear me pushing in and out the clutch a few times and the bearing noise.

the clunk clunk noise when push in the clutch pedal when backing is the other noise I was talking about.

I'm thinking it is coming from the tranny but I'm not sure.
My U joints seem to look fine.

Link for vid.: https://www.youtube.com/watch?v=IIFh...ature=youtu.be

[straight6chevyguy]

Ordered up a clutch kit yesterday, comes with clutch disc, pressure plate, pilot bearing, throw out bearing, and a new slave cylinder.
I'm not going to worry about the input shaft on the tranny right now, I'm sure the bearing is wore a bit but still in tact. I think it will be fine. And like Mr_Rich said, the pilot bearing should support the shaft.
I decided to go ahead and get a new save cylinder just to eliminate any near future problems and since my truck uses the newer internal slave I did not want to put every thing back together and just have to tear it apart again a few miles down the road.

I will be sure to let you all know how it works out.

[straight6chevyguy]

The clutch kit came today!
Not really sure if its a good brand or not but we are sure going to find out!