rnln

This is too complex for me. I hope someone know my new problem… please read
I recently experience scary noise and thump feeling when I engage torque. When I say “engage torque”, I meant when I lift the clutch pedal after shift into gear, and also when I hit the gas pedal after shift into gear.

One afternoon, couple days ago, I heard terrible noise every time I release my clutch and hit the gas pedal after a shifted. I thought something is wrong with my pedal cluster since I felt the vibration there at my feet. The noise is like a bunch of gears were turning and they were loose, and their teeth were not fit well together and they were going to through everything apart. It is in the rear around the engine or tranny area. Each time it last about a second or two, after shift and accelerate. At cruising, it drove normal, nothing happen. I did some tests slowly and precisely. What I did was, after getting up to 3000 rpm on first gear…
1- step in the clutch, pause
2- shift out of first, pause
3- shift into second, pause
4- lift up clutch pedal, pause (without touching gas pedal)
5- depress gas pedal, pause (without touching the clutch pedal)

I did all single steps careful with a pause to reproduce the terrible noise so I can be able to tell which action create this noise. Finally, I found that the noise can be recreate at step (4) and (5) above. If I do it very slow, very very slow and careful, then the noise and thump is less. Note: shifting is very smooth. Cruising is perfect, so the whole time driving is perfect except accelerating after shift, and sudden releasing gas pedal.

Another action can produce the hard thump feeling (very strong thump, without the noise) is lifting up the gas pedal while cruising on highway, then depress the gas pedal again (both action without touching the clutch pedal). When lifting the pedal, everything is normal, but when depressing the gas pedal again, the car jerk and a hard thump as you lug it very hard.

I spent all day today to check tranny fluid and refilled it. I am using redline 75/90NS. This fluid is new, replaced only 2 weeks ago. I also adjust the clutch pedal to raise the pedal up high, still same problem. Then I tried to adjust it 5 or 6 times from all the way high to very low, still same problem.

I also checked engine mounts and tranny mounts. They all look ok. The tranny mounts have some normal wear, but the big notch where it fit into the transmission has bad worn, probably do to the shake/thump. Please look at the picture below.

I have talked some friends and there are several opinions. Some think it’s the tranny gears. But if something wrong with the tranny, then shouldn’t it happen even while cruising? even though I don’t shift or applying torque? Some think it’s the clutch. But if it’s the clutch, or even bearing or anything related, then shouldn’t I be able to shift smoothly? At least it should grind, right?

Anyone experience this problem?

84_Carrera

Check your axles / halfshafts / CV's?
Engine / trans mounts?

Red X on pic for me.

Sorry, saw you checked mounts.

It's not the Omega spring thumping into place after hanging up a bit, is it?

lfe132

I agree with 84 Carrera.
Check your axles. Lift the rear of the car and grab one of the axles in the center of the bar. Now slide the bar in and out. If it moves freely (maybe too freely) you may need grease. Needing grease is not the noise you're hearing but if the grease is all dried out the CV joints maybe worn out, thus your noise.
If its not your axles it may be a mount; trans or motor. Looking at these while they're mounted in the car is not the best way to tell if they're worn. I would suggest you remove them and inspect them.
Also the Pic is also a red x for me.
Good luck.

rnln

Fred,
I am totally lost when you say "It's not the Omega spring thumping into place after hanging up a bit, is it?". Can you explain a little more detail?

lfe132,
I checked the sharp bolts frequently and checked them again yesterday but I didn't grap them and pull/push. I will do that. How much it's allowed to move?
Can I jack up the car one side of a time to try this or both rear wheels need to be in the air?

Thanks.

TT Oversteer

Is your car an early SC with a rubber centered clutch disc? Put the car in reverse (your lowest gear) with the parking brake set. Try to turn the engine over by hand with a socket and breaker bar on the fan pulley nut. Load the driveline in both clockwise and counterclockwise directions. Any excessive play in the driveline or strange noises?

jpyles

I had a similar behavior when my rubber-center clutch went out. I thought it was a motor/tranny mount because it "clunked" with any change of gears or accel/decel with the gas pedal. The rubber center of the cluth had deteriorated (it was the 20 year old original), but there were some metal tabs that would keep the inner and outer halves from disegaging completely. Those tabs engaging were the cause of the "clunk".

The only way I did NOT hear a clunk was if I matched RPMs perfectly in a gear change under low power. Any other time, it felt like there was a very loose link in my drivetrain with lots of "slop", for lack of a better description.

Hope this helps.

rnln

TT Oversteer,
Mine is an 87 with 88 engine, not sure if tranny is 87 or 88 but it's a G50. I tried what you suggested but I couldn't move much since it's too heavy and the belt was sliping. I had to hold the belt with one hand to be able to move the crank a little bit at a time, nothing happen. I couldn't hear anything.
What does it tell me?

jpyles,
You said you heard clunk when changing gear or when accelerate after changing gear? I didn't have any problem while or after shifting at all. It shift very smooth. The problem happen when I lift my clutch pedal and accelerate after gear changed. Any it's not a slight clunk. It's more like a hard thump/jerk/shake plus terible noise. The noise was like gears/teeth were misplaced/loose and were trying to catch on each other. Think about your starter and flywheel are having worn/broken teeth. This sounds similar but multiple of those. When it pronounced the most and both noise and thump happend at once, I was scared the engine and/or tranny will be yanked aparts.

Reading more what you are saying, are you saying your shifting was still fine while you are having this problem?

"it felt like there was a very loose link in my drivetrain with lots of "slop", for lack of a better description."
I do have this feeling.

I went out and while wandering around my baby, I remember I saw some tiny rubber pieces laying on the ground under the tranny while I was taking off the tranny mounts yesterday. The material look like ruber from tire without thread (my tires are still perfect). Please look at the pic below. It's kind of shiny in the pic, but it's not in real.
The blue pin is not from my car

Duke Zink

DING DING DING...Your clutch is gone.

The symptoms and remnants above prove it.

Edgy01

Frankly, I'm amazed that there are still any rubber-center clutch plates still functional in these cars. Those have been less than ideal since about 1983, and should have been replaced. If not replaced the heat has certainly been getting to them for all those years.

rnln

Does anyone know when they stop using the ruber disk clutch?

jpyles

"I didn't have any problem while or after shifting at all. It shift very smooth. The problem happen when I lift my clutch pedal and accelerate after gear changed. Any it's not a slight clunk."

Not sure what this means. I had a clunking sound after a shift, or when I rapidly applied or let off the throttle. It was not a constant grinding sound, just a loud clunk that sounded/felt like something was very loose in the drivetrain.

They used rubber centers thru the 80's, I think, and you can still buy one today and put it on your car. Most people install spring centered, though.

theiceman

right after they fail .....

Sory RNLN
looks like oyur dropping your engine for a look see

rnln

jpyles,
That's it. Seem like that is my problem. I am going to call around for a prof shop. Thanks jpyles. BTW I like your color.
Oh wait, what kind of clutch you finally went with? Would you recommend me the spring center? I did some search on it and found several people saying they can't stand the metal/spring noise. What is your experience?

Mr. Ice,
That's about right but I don't think I can do this task DIY. I hope I can do them all but I think calibrating the clutch is imporant for the clutch life. I affraid I mess it up.

Thanks very much guys. Anyone know how much I am looking at?

theiceman

Too bad RNLN

doing a clutch i think would be a rewrding job. But if you do not have the facilities to remove an engine. Probably a wise move having a pro do it. Pete should be able to give you an idea of shop time .

rnln

is there anyone, I hope Pete would know, proximate cost on this task?
Thanks.