Third gear doesn’t engage

#1
… first thread here?!

Anyway, I have a problem with the automatic on my P5 3 ltr Mk 2 (1964) :( Third gear doesn’t seem to engage. I thought it might have to do with the ’auto gear hold control’, but I’ve tried the upward and downward position at 80 km per hour and it doesn’t make a difference. And I think at 80 constant, it should certainly engage third gear.

Any ideas? Thanks in advance!

Bram
 

tonys

Active Member
#2
A couple of thoughts; have you checked the gearbox fluid level, done from inside the car on the transmission tunnel under/around fascia after removing the carpet on the tunnel. Is the fluid clean?

Are you sure that it's not engaging top? If you pull away gently the car will usually start off in intermediate gear, so you might only notice 1 gear change. On a full throttle start it should change low-intermediate at approx 28mph (45km/hr) and intermediate-top at 57mph (92km/hr). Change up speeds lower with less throttle pressure.

Is yours a coupé (with rev counter) or a saloon? If a coupé what revs are you seeing at 80km/hr? The autos were geared at 20.6mph/1,000rpm (33km.hr / 1,000rpm), so should be approx 2,500rpm (assuming the revcounter is accurate, which they aren't always) at 80km/hr.

The maximum speed in intermediate gear should be 92 km/hr.

It is possible to adjust the low-intermediate and intermediate-top gear change speeds (from underneath) but I don't know how it's adjusted and I don't think that would be relevant to your issue.

I'm not an expert on the internal workings (ie I know nothing) so can't suggest possible internal causes, a search might find more info. or somebody else might have some different thoughts.

Edit: I *think* that if you start with the gear-hold lever in the down position, the car should start off in bottom gear, allowing you to check how many gears it changes into.

Do you know when the fluid was last changed? If the fluid-level checks are fine, and it still definitely isn't going into top gear, then a fluid change (I'm fairly sure that the DG box has a drain plug on the torque convertor as well, unlike the later BW35) would be my first suggestion. I assume the DG box has a filter as well, an internet search should clarify.

Assuming it's the original box and hasn't been rebuilt, I'd recommend checking which fluid should be used because I don't think Dexron type fluid is compatible with those gearboxes.

Hopefully somebody who knows something about these gearboxes will add more info..:)
 
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#3
‘Tonys’, my savior again :) I didn’t know that pulling away gently would skip first gear. I thought I’d spare the old lady and drive like an elderly gentleman, but next time I will put the pedal to the metal and swirf of with screaming tyres and count the gear changes! Also, I will check the fluid level.
Unfortunately, no rev counter (saloon), but it sounds at 80 km/h like more than 2500 rpm. And at that speed, it seems too lively, if you know what I mean: still some power because of the higher rev range, instead of purring away quietly at low revs.

Also, I have big trouble starting the engine when cold - but that will be a different topic, under a different header.

Thanks for now.
 

tonys

Active Member
#5
Not knowing the mechanical condition of your car, it might be worth trying the gear-hold lever 'down' in the first instance, to see if it pulls away in low gear. It might save hammering an old /unknown engine & gearbox ;)
 
#6
Not knowing the mechanical condition of your car, it might be worth trying the gear-hold lever 'down' in the first instance, to see if it pulls away in low gear. It might save hammering an old /unknown engine & gearbox ;)
I will try that, next time. But will it shift to 3rd then? I thought the lever down would ’hold it’ in 2nd (intermediate) and would never get to the highest.

To be honest, not sure what the exact mechanical condition is. I’ve bought it without a lot of info about the history.
 

tonys

Active Member
#7
Once the car's in motion, ie if it's pulled away in bottom gear, moving the 'hold' lever up to its top position should simply mean that the car will then change gear automatically using all gears, ie the hold lever won't be restricting it from changing into top gear.

By starting with the lever down all you are doing is ensuring that the car pulls away in bottom gear and later moving the lever up then stops the transmission holding the car in intermeduate gear, if that makes sense.
 
#8
Once the car's in motion, ie if it's pulled away in bottom gear, moving the 'hold' lever up to its top position should simply mean that the car will then change gear automatically using all gears, ie the hold lever won't be restricting it from changing into top gear.

By starting with the lever down all you are doing is ensuring that the car pulls away in bottom gear and later moving the lever up then stops the transmission holding the car in intermeduate gear, if that makes sense.
It does make sense, just didn’t understand correctly the first time ;)
 
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