Gear Grinding 1st & Reverse, When Engine Warm (Page 1/2)
Doug85GT JUN 04, 12:33 PM
This has been a problem for a few years now. I have not been able to get to the bottom of it. When the engine is cold, it shifts perfectly. The transmission goes into 1st and reverse with no grinding. Once the engine gets to operating temperature it becomes difficult to shift into 1st and it grinds going into reverse.

The clutch has about 4k miles on it. I also replace the master cylinder at the same time as I replaced my clutch. I have replaced all the fluid in the clutch system by vacuuming it out the slave cylinder until clean fluid came out. I am considering replacing the slave cylinder but I am not sure if that would fix anything.

Has anyone else had this same problem? If so, did you find a solution?


88 Base model 4 cylinder

[This message has been edited by Doug85GT (edited 06-04-2023).]

sanderson231 JUN 04, 01:45 PM
I would measure the throw on slave when engine is cold and when engine is hot. Is the throw the same? If shorter when hot perhaps an indication that heat is affecting the slave cylinder.

------------------
formerly known as sanderson
1984 Quad 4
1886 SE 2.8L
1988 4.9L Cadillac
1988 3800 Supercharged

Larryinkc JUN 04, 02:14 PM
V8 Archie has some good clutch info here look under FAQS ARCHISMS

http://www.v8archie.com/v8Archie/home.htm

If you find that you have a problem with your slave cylinder Rodney Dickman has dual seal slave rebuild kits, pistons only and new slave cylinders.

I have had his clutch master and slave cylinders on my car for about 8 years and they work great and have been trouble free as are all of his products that I have on my car.

http://rodneydickman.com/in...505b85e0febd2b30ec6e

[This message has been edited by Larryinkc (edited 06-04-2023).]

Patrick JUN 04, 03:38 PM

quote
Originally posted by sanderson231:

I would measure the throw on slave when engine is cold and when engine is hot.



I would add that the slave needs to move 1-1/8" for proper disengagement of the clutch. If it's not moving that far, there's either air in the system, the clutch pedal is bent, or the banjo is bent.

This issue has been covered here an enormous number of times.
reinhart JUN 04, 06:38 PM

quote
Originally posted by Patrick:

I would add that the slave needs to move 1-1/8" for proper disengagement of the clutch. If it's not moving that far, there's either air in the system, the clutch pedal is bent, or the banjo is bent.

This issue has been covered here an enormous number of times.



I have heard that number 1-1/8" for the Getrag. He has an Isuzu, is that the same number?
Patrick JUN 04, 08:02 PM

quote
Originally posted by reinhart:

I have heard that number 1-1/8" for the Getrag. He has an Isuzu, is that the same number?



My experience (having both an Isuzu and a Getrag) is that 1-1/8" is critical for the Isuzu, and not as critical for the Getrag. (I have no personal experience with a 4-spd Muncie.)
Doug85GT JUN 04, 08:34 PM
I measured the throw. 23/32 cold, 21/32 warm. There is a 1/16 throw lower when the engine is warm.

I took a close look at my clutch pedal. It is higher than my brake pedal, made of steel and is not bent. It is a little loose mostly due to the slop on the banjo. While I was looking at the banjo I decided to flip it around to see if that would have any effect on the throw. That resulted in a 28/32 (7/8) throw after the engine had cook for about half an hour. That is still longer than it was previously cold. It is no longer grinding.

The next thing I need to look into is replacing the plastic bushing on the banjo. I am not even sure if that is a separate item I can buy. If I could replace that with something much better fitting it would eliminate the wiggle in my clutch pedal.
Patrick JUN 04, 08:53 PM

quote
Originally posted by Doug85GT:

While I was looking at the banjo I decided to flip it around to see if that would have any effect on the throw.



The loop must go up.

We covered all this in a recent thread.

Years ago, I made an adjustable banjo to ensure full throw of my clutch pedal.
Doug85GT JUN 04, 10:39 PM
I ordered a brass bushing from Rodney. I think it is take up the extra play in my pedal.

As for the banjo direction, wouldn't the best geometry be the one with the most travel? My car is 35 years old and I am not the first nor even the third owner. Could it be possible that this perfect geometry with the banjo up no longer applies due to possible frame damage or warping prior to me owning it? On my car, there is 1/4" more travel with the banjo pointed down. It is still short of the 1 1/8" that people say is needed but it is a 1/4" closer. I will measure it again when I get the new bushing.

The 88 service manual show a straight rod. Go figure.
Patrick JUN 05, 12:44 AM

quote
Originally posted by Doug85GT:

The clutch has about 4k miles on it. I also replace the master cylinder at the same time as I replaced my clutch.




quote
Originally posted by Doug85GT:

I ordered a brass bushing from Rodney. I think it is take up the extra play in my pedal.



Are you referring to the bushing in the banjo? Didn't your replacement master cylinder come with a new banjo? If so, how did it wear out in 4k miles?


quote
Originally posted by Doug85GT:

Could it be possible that this perfect geometry with the banjo up no longer applies due to possible frame damage or warping prior to me owning it? On my car, there is 1/4" more travel with the banjo pointed down.



If it was my car, I'd want to find out why my clutch pedal alignment was different than everybody else's!


quote
Originally posted by Doug85GT:

I took a close look at my clutch pedal. It is higher than my brake pedal, made of steel and is not bent.



It's the steel part that bends! How much higher is your clutch pedal than your brake pedal? It's supposed to be an inch.