I have an 84 2.5L that was a 4 speed and I converted it to a Isuzu 5 speed (salvaged from an 87) . When I did the swap the clutch and pressure plate had less than 20,000 miles on them and looked fine with no abnormal wear. The clutch and pressure plate are Autozone Duralast (not last) brand with the limited life time warranty. Now, 10,000 miles later the clutch is slipping. The clutch and pressure plate were for an 84 4 speed. The Isuzu 5 speed was also professionally rebuilt with all new brass and bearings. The transmission shifts without any problems and there is no abnormal noise from the transmission.
I do not pop the clutch or race the car. It is my daily driver and I baby her.
What is the best clutch and pressure plate to buy for the replacement?
Do I buy a 84 4 speed clutch and pressure plate or do I buy an 87 Isuzu clutch and pressure plate? I know i use the Isuzu throw-out bearing.
I read in one archive that an clutch & pressure plate from a 2.8L V-6 will fit the 4 cylinder and has a higher torque rating. Is this this the best daily driver choice?
Provided the pressure plate will bolt up, and the assembled height is the same, you can probably use a V6 clutch. It'll use a larger diameter disk. You'll still need the Isuzu throwout bearing.
Considering that the clutch isn't very old and hasn't been beat on, I'd suspect an oil leak from the transmission. If the input shaft seal leaks, it will contaminate the clutch with oil, causing it to slip. You'll still need to replace the clutch. Because the oil contamination basically ruins the friction disc. But while you have it all apart, check for an oil leak.
The clutch and pressure plate were for an 84 4 speed.
I know i use the Isuzu throw-out bearing.
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Originally posted by Gall757:
The clutch part numbers are different for the 4 speed vs. the 5 speed. You need a clutch specific to your transmission...
Okay, I'm confused now. I've understood it's the throwout bearing that is matched to the tranny. I suspect then that all pressure plate and clutch disc sets are interchangeable (although obviously a larger diameter one would be used with a V6). In other words, a pressure plate and disc for a muncie 4-spd should work fine with an Isuzu 5-spd... as long as the correct throwout bearing is used.
I agree with Blacktree above about a possible oil leak. There's gotta be a reason why that clutch is slipping after only 30,000 miles on a duke.
Does your car leak any oil? I had my rear main seal go out on my newer 15k mile clutch, and was so pissed. When I pulled the motor from the transmission, my rear main seal was leaking and flinging oil on the flywheel and pressure plate, causing the clutch to slip. I should've replaced the rear main when the clutch was done before, but I just forgot.
I agree with the oil premise. A 2.5 doesn't have enough power to destroy a clutch driven as you describe. I know that when you install a clutch you need to carefully clean the flywheel because any oil on it and the clutch will not hold. (I learned the hard way) I use brake cleaner on the flywheel before assembly
Originally posted by Patrick: Okay, I'm confused now. I've understood it's the throwout bearing that is matched to the tranny. I suspect then that all pressure plate and clutch disc sets are interchangeable (although obviously a larger diameter one would be used with a V6). In other words, a pressure plate and disc for a muncie 4-spd should work fine with an Isuzu 5-spd... as long as the correct throwout bearing is used.
I suspect the same thing, however, at the Fiero Store the discs and pressure plates for the two transmissions have different part numbers.....that's not to say they are different, but it seems like they would not go to the trouble of renumbering if they did not have to.
I bought my clutch from Carolina Clutch, a really great place with good, honest people. My understanding is that, unless your racing like a mad man, an OEM replacement will work fine. Just contact above, and you should be fine (in my opinion). bb
...at the Fiero Store the discs and pressure plates for the two transmissions have different part numbers.....that's not to say they are different, but it seems like they would not go to the trouble of renumbering if they did not have to.
Out of curiosity I looked at "clutch friction discs" at RockAuto and noticed the same thing as you, although I also noticed the '84 duke supposedly takes the same disc as the '85-'88 V6 engines. That seems odd to me.
I have not been using hardly any engine oil. I have not noticed any leaks under the car. I was at 3000 miles on this oil change and used less than 1/4 of a quart when I checked the oil a week ago. However I park the car on gravel, so it would be hard to notice a slight oil leak. The engine was rebuilt approx 30,000 miles ago.
Of course the clutch has to be looked over when I remove it from the car. I am sure I will find out real quick if it a oil leak or a crappy clutch and pressure plate. I have had issues in the past with Duralast clutch master cylinders and a couple of other Duralast parts on my Fiero.
I have not checked the transmission for for loosing fluid ( I used Pennzoil Synchromesh).
I am using an Isuzu throw out bearing.
[This message has been edited by A Woodward (edited 02-12-2014).]
Check the clutch release arm by hand and note whether or not there is preload beyond what the slave cylinder applies on it., In other words you should be able to collapse the push rod into the slave cylinder some. If there is a mismatcted part causing pressure to be applied to the pressure plate release springs after bolting the transmission up then that would be the problem. On a gravel surface there should be plenty of dust to reveal a chronic oil leak as it builds up in the leak area on the tranny or motor, so you would be able to see the residue rather easily if there was a leak.
If by chance the disc was installed backwards that will ruin it in short order to.
Use the 4 speed clutch. It is 9" like a V6 clutch, the 2.5 Isuzu clutches are only 8.5"
Use the 5 speed throwout bearing. It is specific to the transmission. DO NOT LOSE THE CLIP, it is not available separately, you'll have to either buy another bearing assembly or rely on the kindness of somebody to give you a used clip.
