96' 850 problem torque converter/lock-up clutch

144ps · Post by **144ps** » 01 Dec 2025, 02:34

Hello everyone,
I have a problem with my 1996 Volvo 850 automatic (103 kW/144 hp) with 230,000 km.

Sometimes I experience jerking/stuttering when starting off at traffic lights in 1st gear if I accelerate hard. Sometimes, however, it's a jerky start, like when you release the clutch in a manual transmission, then press it again and then release it again.

The main problem, however, is that I feel vibrations throughout the vehicle when driving at a constant speed (60-90 km/h) on the highway. These vibrations have become more noticeable over the past few weeks, but they are not always noticeable. It feels as if it is influenced by the transmission's driving mode (lock-up clutch on/off..?). It is a vibration that goes through the entire body and is particularly noticeable in the seats and legs, as well as in the steering wheel. Very annoying in the long run.
I have already had the wheels balanced, but I don't think that's the problem, as the vibrations are not always present.
Otherwise, the transmission shifts perfectly, gear changes are almost imperceptible, and the transmission feels completely normal.

The arrow in the speedometer is not active. Error code 114 mode selector switch is stored. When the error is deleted, it reappears immediately, but does not seem to affect operation. All driving modes can be set using the switch.

Does anyone have any experience with problems with the torque converter or torque converter lockup clutch on the 850, or any idea what the problem might be?

The following have been replaced so far:
Both drive shafts (new)
All engine and transmission mounts
Drain & fill ATF four times in april 25' (oil was brown, until now its clear red)

Thanks and best regards from Germany

Post by **misha** » 01 Dec 2025, 03:15

Doesn't matter if wheels are balanced recently.
Could be bad tyres or bent rim(s).
I had a vibrations you mentioned after fitting a brand new summer tyres.

After fitment i had vibrations around 90km/h...2nd balance around 100km/h...3rd balance after 110km/h...4th balance around 120km/h.

Balancing machine always reported 0 after balancing.

Problem was poor balancing because the weights were installed just a tick after the point where machine laser was pointing.

2nd problem was a slightly deformed one tyre...yes brand new tyre which needed 80g of weights on the outside.

144ps · Post by **144ps** » 01 Dec 2025, 03:31

Thank you, at least one wheel lost a balancing weight, thats why i balanced them in first place.
I will try to fit another pair of wheels.

Post by **misha** » 01 Dec 2025, 05:56

There are so many tyre shops which doesn't remove old weights before new balancing...they just add more if needed...resulting in bad vibrations which was hardly noticeable before balancing.
Now....i just visit one or two tyre shops because of that and avoid others.

aeg · Post by **aeg** » 01 Dec 2025, 14:32

Torque converter lockup will never be engaged in 1st gear, so it's not responsible for jerky starts.

Post by **abscate** » 02 Dec 2025, 03:14

aeg wrote: ↑01 Dec 2025, 14:32 Torque converter lockup will never be engaged in 1st gear, so it's not responsible for jerky starts.

I missed this , it’s great when the Collective Brain chimes in on a tough one. Thanks, @aeg

Post by **Grantkat** » 02 Dec 2025, 08:06

+1 on tires/rims

Before I found a trustworthy tire shop, i would have a similar issue when changing tires or buying new ones. When my tire guy started his own shop, problem solved. I took my new tires <100 miles into him and he immediate spotted the issue described above. the tires were balanced with old weights on them. He took all weights off balanced and the difference was night and day.
if not weights, look for defects, flat spots etc on the tire itself.

144ps · Post by **144ps** » 06 Dec 2025, 01:58

Thanks for all your answers!
You were right, it was the wheels. They were balanced in November, but either something went wrong or the wheels have radial runout.
I've now fitted my Cetus rims and the vibrations on the highway have disappeared.

However, the ATF doesn't look clear red, so I ordered another canister to change it just to be on the safe side. Maybe that will also get rid of the stuttering when starting off.

Post by **misha** » 06 Dec 2025, 02:19

Could be spark plugs,cap & rotor or spark plug wires.
Is check engine light on?

144ps · Post by **144ps** » 09 Dec 2025, 02:29

misha wrote: ↑06 Dec 2025, 02:19 Could be spark plugs,cap & rotor or spark plug wires.
Is check engine light on?

No, the check engine light is not on. There are no errors stored.
The cap and distributor finger are almost new, so the stuttering is definitely coming from the transmission. I'll change the oil first and see if that fixes it.