Overdrive on/off issue

[Profister]

I wonder if somebody came across the issue I am having with overdrive on/off. Switching overdrive off does not make any difference for rpm although the indicator light turns on. I tried it in different driving conditions, up to 120 km/h and did not see any difference. For example, driving at 100 km/h with 2800 rpm and switching overdrive off is not making rpm higher. Does anybody know what it can be?

[coaxial]

the switch itself is notorious for being broken

[Profister]

Hmm. Why does the 'overdrive off' turn on then?

[jaggedfish]

Might be you are driving too fast for the tranny to shift down.... I know most vehicles have a lockout to prevent the engine from over-revving. My overdrive kicks in at about 60 kmh if I'm not accelerating too hard. Try idling downhill between 60 to 70 kmh and hit the switch... if it doesn't downshift, you have a problem.

Good luck!

Edit... by the way... at high speed the O/D OFF would still light up because the switch has been switched but the trans hasn't downshifted due to rpm's.

[Profister]

Thank you. If you are right then it works differently from my other cars; I had Suzuki Esteem auto, Grand Vitara auto and now i own SX4 auto. All 3 are downshifting with 'overdrive off' at any speed from 50 km/h and up to 130 km/h at least. I will play with at various conditions. Thanks again.

[coaxial]

Or get a 5 speed manual

[Profister]

Too late.

[Mystery Machine]

Sounds like there might be a connection problem between the button/switch and the gearbox (i.e. the gearbox end)

Obviously a signal is getting through from the switch (i.e. the switch IS working) otherwise you wouldn't be getting the OD on/off light on the dash.

I'll have a look into the wiring and see if I can get any info that might help?

One way or another, we'll get you sorted...

Bruce.

[Profister]

Thank you Bruce. I really appreciate your help.

[Green1]

I agree with the bit about over-revving... I have yet to see a car that will downshift "no matter what" when you turn off the overdrive, imagine if you're close to redline already and hit the button... some serious damage could result... better to see how it behaves at lower revs.

[visotzky]

Here in Hope there is a Deli owner who is computer challenged and is therefore not a club member. Apperently his engine over reved and blew up when he accidently hit the button at 120kph, just saying be careful. Actually his engine blew up a second time, 10000 bucks or so he has sunk into his engine in less than a year, it's practically new now.

[Profister]

I really appreciate everybody's input as this is my first (but not last) topic on this forum with troubleshooting. I am just trying to explain that the situation with 'overdrive on/off' in my Delica is completely different from my previous experience and does not make any sense. So if there are 2 separate wires running to the light and to the gear box than the second one is definitely cut.

[Mystery Machine]

So if there are 2 separate wires running to the light and to the gear box than the second one is definitely cut.

Not necessarily - there is more to it than a few wires. Give me a couple of days to pull all the stuff together (I'm away all day today) and I should have some pretty accurate info for you to digest...

Sorry I can't be more helpful right now, but I assure you it'll be worth the wait!

Bruce.

[Profister]

Thanks again Bruce; Patience is my second name .
Meanwhile I am installing a new radio/cd/mp3 player.
I will also appreciate if someone can give me the normal rpm readings and upshifting speed points for Delica so I can compare them with mine. Thank you in advance.

[marsgal42]

Do you have reason to suspect that your transmission is malfunctioning?

My own observations are that the transmission will lug down to 1500 RPM before it even considers downshifting on a hill, and it takes a very heavy foot to get above 2500 RPM before the transmission shifts up. Most non-highway driving is around 2000 RPM. It is, fundamentally, a small truck diesel engine.

Foot to the floor will wind right up to the 4500 RPM red line, but you'd better have a mechanic in the family if you're going to do that very often.

...laura