1988 4cyl MT2/Isuzu 5 speed: New Clutch Starting to Slip After ~1500 miles (Page 2/3)
gjgpff SEP 27, 04:20 PM

quote
Originally posted by reinhart:


Why is it only slipping in 4 & 5 though if oil contaminated?
AND
Did your mechanic look at the old clutch disc to see if it was worn evenly, or what caused the failure?

Did he give you paperwork for machining the pressure plate or was it a new one? If he just reused the old one, it could cause faster failure. On mine, one of the springs was bad which I noticed when I tore it apart. A bad spring could cause slippage.




All,
First of all, thanks for all the replies. Specifically with respect to slippage in the high gears I can't be sure it isn't slipping in lower gears, but the problem is intermittent and it may well be that I've noticed slippage in the high gears because the car spends most of its time in those gears, and also those are the gears for freeway driving where I have a little more time to monitor tach, oil pressure, temp, etc. I've only just started paying more detailed attention to gear changes, so I expect I'll learn more soon enough.



quote
Originally posted by fieroguru:
I suspect the bushings on the cross shaft for the clutch release bearing are dry and starting to bind. The 4cly pressure plate has a very light clamp load, so anything that keeps it from fully clamping the clutch disk will cause an issue.



So, if this is the case, the transmission/engine will have to be separated, right?



quote
Originally posted by Blacktree: The OP mentioned replacing seals in the transmission. I'm guessing the axle seals? Do you know if the input shaft seal was replaced? If it leaks, it will contaminate the clutch with oil. When you remove the clutch, check for signs of oil seeping out of that seal.



Yeah, they were the axle/output seals. One was leaking pretty badly and the other was seeping. I was pretty stoked to get those seals replaced successfully. Unfortunately, I'm not really set up to do a clutch job, the garage needs to be cleaned out first, so I might have to outsource this. Is it possible to diagnose the larger problem of oil seepage from the input shaft without dropping, or hinging down, the subframe? Right now the car has no obvious oil leaks.

reinhart:
Since you're in the OC, do you happen to know of any reputable transmission/clutch guys/gals that you would take your Fiero to? Also, you wouldn't happen to be the owner of the Yellow 88 GT I see on Euclid some mornings and Evenings heading in the opposite direction? I'd be white 88 notchback

Did you mean machining the flywheel? The flywheel was machined, but the pressure plate, clutch disk, and throw bearing were new: LUK... something. Do you have a brand you recommend? The Fiero Store Heavy Duty one is kind of pricey, and I'm not sure I really want a clutch like that if I'm trying to get the longest life out of my transmission, but maybe I'm wrong on that.

Right now I'm going to focus on the clutch system. It could be the transmission, but fixing the transmission is just fixing the clutch system + $500!

Hey, this reply is kind of a mess. I'm just gonna stop here! Again, thanks! I can't imagine owning my Fiero without having a site like PFF.

[This message has been edited by gjgpff (edited 09-27-2020).]

fieroguru SEP 27, 04:24 PM

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Originally posted by Dennis LaGrua:

I seen one instance where a bad distributor O ring leak caused some oil to find its way on the clutch and this caused a slip.




Not going to find one of those on an 88 4 cly.
Blacktree SEP 27, 08:49 PM
@gjgpff - You could remove the clutch inspection plate, and peek inside the bellhousing. If oil is seeping into the clutch, the spinning of the engine should fling some of it into the bellhousing.
olejoedad SEP 27, 08:58 PM
While it's apart, replace the rear crank seal.
Were you able to inspect the parts that were replaced?
They can tell you alot.
gjgpff SEP 27, 11:18 PM

quote
Originally posted by Blacktree:

@gjgpff - You could remove the clutch inspection plate, and peek inside the bellhousing. If oil is seeping into the clutch, the spinning of the engine should fling some of it into the bellhousing.



I'll do that, thanks!


quote
Originally posted by olejoedad
While it's apart, replace the rear crank seal.
Were you able to inspect the parts that were replaced?
They can tell you alot.



I know i told the first guy to not replace the rear main seal unless it was leaking because the car has only 55k miles and the seal is pretty protected from the elements, but I might have it done this time.

[This message has been edited by gjgpff (edited 09-27-2020).]

Joseph Upson SEP 28, 10:02 AM

quote
Originally posted by Patrick:

This makes me a little suspicious as to whether your mechanic ever really got the clutch fully disengaging/engaging properly.

Did the clutch feel 100% normal when you got the car back from the mechanic with the new clutch? No slippage when engaged, and it disengaged fully?

Just curious... does your clutch pedal sit above your brake pedal while at rest?




This is definitely an area to review. One of the tricks I've implemented for troublesome Fiero clutch hydraulics as a result of difficulty getting a remanufactured part to work properly, was to increase the preload, by putting washers behind the slave cylinder mount, or even putting something inside the body of cylinder itself to increase travel. Go to the slave cylinder at the transmission and assess the preload on the release arm. You should be able to push the lever back toward the slave cylinder a small, but noticeable amount without serious effort. If it is firm and not easy to move, it's possible you may have too much preload on the clutch arm from a part mix up.

Replace the rear main seal if you're in there, they don't stop aging and drying out because the car hasn't been driven much and may deteriorate faster as a result, as did the clutch.

[This message has been edited by Joseph Upson (edited 09-28-2020).]

Patrick SEP 28, 02:18 PM

quote
Originally posted by Joseph Upson:

...it's possible you may have too much preload on the clutch arm from a part mix up.



Yep, that's the potential outcome of a possible hack repair job. Another example of this would be an excessively long "custom" length rod between the slave and clutch arm.
gjgpff SEP 29, 10:23 AM
Ahhh, this has been observed! To the credit of our mechanic, he did show me that some guy before him had done exactly that with the slave cylinder using some really odd, like "found on the floor of the shop" washers. I checked and his fix doesn't have that specific issue, though I seriously regret not making him use the Rodney Dickman master and slave.

Right now I have a bunch of quotes for just diagnostics from various transmission shops. I'm leaning towards the guy who's charging $135 since he's said he "Doesn't like working on Fieros" and that seems to be an appropriate and legitimate response. Everybody else is like "Bring it in and we'll have a look".

I really wish I had a space where I could work on this right now, just so I could satisfy myself that I was getting proper travel and maybe get that clutch pedal sitting right, or know why it isn't. I might have some space to work on the car in about a month, so I might wait. This weekend I'll definitely check the travel, slave, etc and report back to the forum.

The other side of it is that the car has a slipping clutch but is driveable and I'm pretty sure that that is going to be a gold mine of information to a good transmission/clutch guy. If he lets me supply RD parts, I might go that way.

Thanks again!
edfiero SEP 29, 10:33 AM

quote
Originally posted by fieroguru:

It is normal for clutches to start slipping in the high gears. In lower gears it is easier to move the car than slip thr clutch, in the higher gears it takes much more torque to accellerate.



THIS!! I think you'd surely notice a slipping clutch more in 1, 2 or 3 than you would in 4th or 5th. Maybe its harder to see the car reving in the low gears since that is what it normally does there, but you would surely feel the lack of acceleration as it revs.

But agree you shouldn't be having the problem after only 1500 miles.
gjgpff SEP 29, 12:01 PM

quote
Originally posted by edfiero:


THIS!! I think you'd surely notice a slipping clutch more in 1, 2 or 3 than you would in 4th or 5th. Maybe its harder to see the car revving in the low gears since that is what it normally does there, but you would surely feel the lack of acceleration as it revs.

But agree you shouldn't be having the problem after only 1500 miles.



Ahh, I owe you an update. Last time I drove it I noticed it slipping a little in 3rd, so it looks like it's working it's way down, and again, I can't say for sure that the slippage happens more in 4th and 5th, that's just where I've noticed it because I spend 70% of my time in those gears and when I'm in those gears I am expecting the tach to be steady so I'm going to notice slippage more in those gears. Now I've seen it in 3rd. I also don't want to drive it so much now because I think that it would be forensically valuable to a real transmission/clutch guy to have a driveable car. I have the feeling that, if it comes to it, it would make the diagnosis 100 times easier.

but let's say it isn't slippage, maybe something bad has happened to my transmission?

[This message has been edited by gjgpff (edited 09-29-2020).]