Gears/drive

[JillyNipple]

My newly acquired Smart Pulse Cab semiauto has a problem with gear selection when it's been running for a while and is warm. It shows the gear number on the display but seems to not engage. Sometimes it will suddenly engage, sometimes I have to stop and let it cool down. Other than that it runs a treat.
I expect there are a zillion possibilities - clutch, selectors, thin oil (??), electronics? It has been stood pretty much for 2yrs or so.
Clues?? Also can you suggest a good repair centre? Thank you 😋😋😋

[mikerj]

If the clutch is suddenly engaging and causing the car to lurch forward then it's most likely a problem with the clutch actuator, which is quite a common problem. The actuators are very exposed underneath the engine and water can get in if the rubber gaiter is loose or has perished, and the lubricating grease can dry out making the mechanism sticky. Pulling back the rubber gaiter and squirting generous amounts of white lithium grease into the insides can often help. This video shows what to do. Also a good idea to use small cable ties to secure the rubber gaiter onto the shaft and body of the actuator afterwards to prevent water ingress.

If the actuator needs replacing they can be bought for about £150 new if you shop around.

There are quite a few good independent Smart specialists but would be useful to let us know what area you live in.

[ossy]

Which color smart do you have ?

[JillyNipple]

Mikerj- sorry I meant to say I'm just south of Birmingham. Your reply is very helpful, thank you.
Ossy - it's red and black

[tolsen]

The red and black ones are really bad for contracting gear change and clutch trouble.

[JillyNipple]

Ah yes, I thought that might be the case!! 🤣

[tolsen]

Colour is not but water ingress, corrosion and vibration are main causes for Smart 450 gear and clutch trouble.

Transmission wiring harness vibrates and bare copper of cables will be exposed to the elements if cables are allowed to vibrate and chafe against something (usually the intercooler support cradle) for a sufficiently long time. The problem is very common on Smart cars that have been worked on by garages. Does not seem to matter much whether worked on by a Smart dealer or an independent.

Clutch actuator and gear shift drum angle sensor are prone to water ingress and corrosion.

For angle sensor the cure is to remove sensor, clean seal area where it sits at left side of transmission and refit with protective grease on seal area and on thread of bolts that hold sensor to transmission.

Water and dust ingress into clutch actuator is caused by corrosion on two seal areas for clutch actuator boot:
1) Where boot seals against clutch actuator rod.
2) Where boot seals against clutch actuator housing.
Clean above areas using wire brush and suitable file. Then apply silicone grease and refit boot. Never use mineral grease as that will ruin rubber boot making it swell so you never get any seal.

Nearly every three month I raise rear end of my Smart car to check clamping of wiring harness, condition of clutch actuator boot, drive shaft boots, springs, drive belt etc etc. Mine, a diesel 450 Cabrio has done 249.000 and still going strong. Has been the most reliable car I have ever owned and is remarkably cheap to run.

[JillyNipple]

249k!! That's incredible! Well done you! I shall follow your guidance and have a mooch underneath. I'll keep you posted.

[tolsen]

249k!! That's incredible! Well done you! I shall follow your guidance and have a mooch underneath. I'll keep you posted.

249,000 km not miles. That is 65% of the distance all the way to the Moon. Hope to get there one day.

[JillyNipple]

A smart on the moon - that would be something!

[tolsen]

A smart on the moon - that would be something!

Yes that would surely break the news.

[JillyNipple]

Ok so we've greased the actuator, checked the gaitor and secured it. Then we took it out for a run and to take advantage of the supermarket car park so we could do a fair bit of forward and reverse gear changes - with good results.
Thank you.

I wonder now if you can offer any advice on the following; imagine I'm at traffic lights and I put the gear into neutral, then put it into 1st there is no drive connection. If I then try R there is still no drive connection. If I put the gear to N then turn the ignition off and then back on and select a gear I get drive connection again. This happens intermittently and it almost seems more electronic than mechanic. Any clues??
Thanks for this.

The car is such a pleasure and so much fun - I'm loving every minute of having it!

[Thrumbleux]

I wonder now if you can offer any advice on the following; imagine I'm at traffic lights and I put the gear into neutral, then put it into 1st there is no drive connection. If I then try R there is still no drive connection. If I put the gear to N then turn the ignition off and then back on and select a gear I get drive connection again. This happens intermittently and it almost seems more electronic than mechanic. Any clues??
Thanks for this.

Try.... starting the car and selecting 1st gear by pushing gear lever left then forward - without putting a foot near the brake pedal. Drive off and if lights on the dash appear when you first brake, then brake switch is faulty.

[JillyNipple]

Thrumbleux - which lights am I looking for?
So, i did what you said, start, gear selector left then forward, not touching the brake pedal, car went into first gear and I drove off, but no lights on dash?

[Thrumbleux]

Thrumbleux - which lights am I looking for?
So, i did what you said, start, gear selector left then forward, not touching the brake pedal, car went into first gear and I drove off, but no lights on dash?

ABS/ESP warning light - on first application of footbrake once driving.