Strange slip/shudder Manual transmission 3rd gear?

[actionstan]

Hello All,

This is regarding my 99 Saturn Sl1 with 145k miles and a manual 5 speed transmission. This is a odd issue I am having a hard time pinning down..

When ever I am in 3rd gear(this is the only gear this happens in), and there is a heavy load.. for instance going up a steep grade with the AC on, I will get a slipping/shuddering/mis-firing(maybe?) feeling. It seems like its alleviated slightly if I shift into 3rd from a higher RPM(which I try to do anyways to avoid bogging the engine), but it is still there.

I am not sure if this is a transmission issue.. or engine issue, it is odd since this is the only gear it seems to happen in as well.

Let me know your thoughts, and what you would check first.

Thanks!

 

[Quest]

when was the clutch + pressure plate last serviced?

*suspect slippage*

Q.

 

[expat]

Are you saying it gets better if you gear DOWN?

I would think you may have clutch slip.

 

[actionstan]

As far as I know, the clutch assembly is the OE assembly. Its probably getting close to needing a new clutch, however if the clutch was slipping, I would think it would happen in all gears. I can do a wot run in 2nd or 1st, and it does not seem to slip or shudder, ac or not. I just think its odd that its happening in 3rd, unless it has to do something with the torque my engine is putting out at that specific instance, at that specific gear. When I downshift or upshift it seems better, as long as I am in the appropriate rpm range.

 

[Quest]

assuming that it's Oe with 145k on the odo, your pressure plate fingers would have become weak anyways, so slippage maybe the cause.

The only way to deal with this is to get a clutch kit (pressure plate, friction disc,+ throwout bearings), take off the gearbox and perform a RE and RE with inspection.

Q.

 

[bdcardinal]

Usually a slipping clutch first shows signs in higher gear in my experience.

 

[actionstan]

Hmm.. I am not surprised it is the clutch, I knew it would be soon.. Whats the harm if I continue to drive on it for now, until it gets worse, the only thing I can think of is flywheel damage?(I may replace the fly wheel as a measure of security anyways, they aren't very expensive..)

 

[aquariuscsm]

Originally Posted By: bdcardinal
Usually a slipping clutch first shows signs in higher gear in my experience.


^This

 

[expat]

Originally Posted By: actionstan
As far as I know, the clutch assembly is the OE assembly. Its probably getting close to needing a new clutch, however if the clutch was slipping, I would think it would happen in all gears. I can do a wot run in 2nd or 1st, and it does not seem to slip or shudder, ac or not. I just think its odd that its happening in 3rd, unless it has to do something with the torque my engine is putting out at that specific instance, at that specific gear. When I downshift or upshift it seems better, as long as I am in the appropriate rpm range.


Normally clutch slip can be most easily detected in 3rd.

In the lower gears, torque multiplication normally hides the slip (you would have to be going up an awfully steep hill to be at WOT at maximum engine torque for slip to occur)

When the slipping occurs, apply very light pressure to the clutch pedal while maintaining the same throttle position. You can expect the clutch to slip like crazy, and take a second or two to regain grip when you take your foot off the clutch.

Personally i would have expected your clutch to last longer. But that depends on usage.

 

[expat]

Originally Posted By: actionstan
Hmm.. I am not surprised it is the clutch, I knew it would be soon.. Whats the harm if I continue to drive on it for now, until it gets worse, the only thing I can think of is flywheel damage?(I may replace the fly wheel as a measure of security anyways, they aren't very expensive..)


Yes, you could get some Blue patches on the FW.
If you fix it now, you might get away with just a Disc, Pressure plate and release bearing (I also like to replace the FW pilot bearing)

But if you drive carefully ( Gear down, not causing it to slip) you can carry on driving for quite some time.

 

[Corvette Owner]

Try flooring the gas in a high gear, if rpms increase without an increase in mph, your clutch is slipping and probably needs replaced.