Diagnosing notchy shifting in a 99 S70 T5m

Levinicus · Post by **Levinicus** » 16 Apr 2017, 00:54

Just got my first Volvo! Woo! Did my homework and checked every last thing I could reasonably check before handing over cash. On the test drive and for about 2 weeks after it shifted butter smooth... but of course, what do I do with a brand-new-to-me turbobox? I beat the tar out of it!

About 2 weeks after purchase, I noticed one morning that the shifter was no longer smooth going between gears while moving. At the same time, I noticed a noise with the car in neutral and the clutch engaged. Did some research on the noise and found that it sounds like a failing DMF (I found examples on youtube). My hypothesis at this point is that I was too aggressive and damaged the DMF, creating play in the bearing between the two masses. That in turn causes the friction surface to drag slightly against the clutch, imparting torque upon the input shaft of the tranny, forcing the synchros to struggle with their job when changing gears. Does this sound plausible? Anyone else have alternate hypothesis? We can place bets! IF I can't come up with a more solid diagnosis (and the mechanic can't either) then I am going to go ahead with an SMF conversion and new clutch kit.

More info: According to P.O. the car got a T/B, rebuilt transmission, clutch, and flywheel in 2012, 50k ago. No paper records unfortunately, but the T/B cover has an odometer reading in tipex that would seem to validate the T/B job at least.

Glad to be a part of the family!

Post by **tryingbe** » 16 Apr 2017, 07:29

Were both the master and slave clutch cylinders replaced?

Post by **rspi** » 16 Apr 2017, 08:15

Welcome to Volvoland.

You may want to cut back on the abbreviations, so other's don't have to guess as to what you are taking about. Yes it is possible to destroy a clutch, transmission, etc. in a few days. These cars have 3 primary clutch options, standard, R and Sport.

Levinicus · Post by **Levinicus** » 16 Apr 2017, 10:59

tryingbe wrote: ↑16 Apr 2017, 07:29 Were both the master and slave clutch cylinders replaced?

Not to my knowledge. I inspected the master from inside the car and didn't see any leaks. I'm disinclined to suspect the hydraulic clutch because I'm all but certain that I caused the problem by driving too hard... The hydraulics don't seem like a system that would fall victim to hard driving. Am I wrong?

Levinicus · Post by **Levinicus** » 16 Apr 2017, 12:28

rspi wrote: ↑16 Apr 2017, 08:15 You may want to cut back on the abbreviations, so other's don't have to guess as to what you are taking about. Yes it is possible to destroy a clutch, transmission, etc. in a few days. These cars have 3 primary clutch options, standard, R and Sport.

I'm putting in the Valeo single mass flywheel conversion kit. It comes recommended.

Post by **tryingbe** » 16 Apr 2017, 12:33

Levinicus wrote: ↑16 Apr 2017, 10:59
tryingbe wrote: ↑16 Apr 2017, 07:29 Were both the master and slave clutch cylinders replaced?
Not to my knowledge. I inspected the master from inside the car and didn't see any leaks. I'm disinclined to suspect the hydraulic clutch because I'm all but certain that I caused the problem by driving too hard... The hydraulics don't seem like a system that would fall victim to hard driving. Am I wrong?

Probably not going to help, but I'd do a quick bleed first to make sure there is no air bubble in the system before anything else.

Levinicus · Post by **Levinicus** » 16 Apr 2017, 16:18

tryingbe wrote: ↑16 Apr 2017, 12:33 Probably not going to help, but I'd do a quick bleed first to make sure there is no air bubble in the system before anything else.

I've heard that it's very difficult to bleed the clutch in these cars without making the problem worse. I am only a novice DIY-er. Should I attempt it?

Also, I'm wondering if anyone can tell me how quickly this mild clutch drag will kill the synchros. Like I said before, the shifter isn't grinding it's way into gears. It just went from being perfectly smooth to being... less than perfect. Mildly notchy. Unfortunately I have to drive this car 40 highway miles a weekday. I've been babying the transmission and pushing the shifter gently into gear to give the synchros time to overcome the clutch drag... Is this the wrong approach? Should I shift quickly to minimize wear on the friction cone? I've lost one Swede to a transmission problem before (came with the car), I don't want to lose another!

Post by **j-dawg** » 16 Apr 2017, 20:23

Has it been cold out? The M56 is super stiff until it warms up.

Levinicus · Post by **Levinicus** » 16 Apr 2017, 22:57

j-dawg wrote: ↑16 Apr 2017, 20:23 Has it been cold out? The M56 is super stiff until it warms up.

It's been in the 40s-50s in the morning, but 60s-70s in the afternoon. Makes no appreciable difference. I did a drain/fill with Redline MTL too, again with no difference.

Post by **abscate** » 17 Apr 2017, 04:23

I doubt you can kill a relatively new clutch or flywheel in a few weeks. But, you can't diagnose much without taking it apart.

I've got almost 200k miles on my original but most were Momiles