New to this forum-transmission query.

[Dunc]

Hello - Im Duncan, new to this forum.  Im trying to resurrect a semi- derelict Volvo 66. Managed to get it running albeit roughly. Though it wont run without choke.
Ive been starting it in Park the revs have exceeded 2000RPM which I have now read in the manual is not a good idea.
Initially the car would drive in forward and reverse although gear selection was difficult ( especially going forwards where it would grind before engaging). After moving it in and out of the garage a few times so I could work on it outside it now seems to be jammed 'in gear'. I.e when I turn the key the transmission seems engaged and the engine therefore wont turn over and start.
Final thing -the transmission lever will move from park to about where neutral is and no further -it feels loose and vague 
Would be very grateful for some advice to as to what I should start dismantling. Variomatic transmissions entirely new to me.

[andrew]

Hi, Duncan, and WELCOME to the world of Dafs and Volvos!

The Volvo 66 is basically a Daf 66 with changes to the transmission. The gear changes have to be carried out when the engine is ticking over, and this tick-over has to be at a speed lower than the point at which the automatic clutch engages, so the first thing you need to do is adjust the engine to reduce the tick-over speed to about 750 (+/-25) RPM. At this point the gear selector should move easily between the 4 positions of park, reverse, neutral and drive. Daf 66 cars had only three positions, as they didn't have a park option. The carburettor is a Solex side-draught one, tucked under the spare wheel and is fairly conventional, if you know your way around a carburettor.

I'd recommend joining the Daf Owners Club to obtain a huge amount of information and help from experienced club members, who will be only to pleased to assist!

We like pictures on the Forum, too!

[Dunc]

Hi Andrew and thanks for your help, every little bit of information at this point is going to help me!

In response to your comment, I have had the carb off and cleaned out all of the ‘circuits’ that I could see, and with some fresh fuel that got it started in the first place (it arrived as a non-runner). Sadly it runs rough and once warmed through it doesn’t like the choke being taken away! I can get the revs down a bit but not anything like tickover. So, with it revving a bit I have put it in gear and shunted back and forth a few times and ‘gear’ selection was a bit unwilling. It did go back and forth about half a dozen times though....
What has happened though is that it seems stuck in gear. What I mean is, when I turn the key, the starter engages, but you can feel that it’s trying to turn the whole transmission system right down to the wheels! Needless to say, it can’t manage that so not a lot happens. Moving the rather vague transmission lever back and forth I don’t seem able to find any position where the transmission dis-engages. For what it’s worth, the lever only travels between Park, and roughly where Neutral is - it won’t go all the way back to Drive, but then maybe it shouldn’t?!

What I am anxious to avoid is trying to get the transmission off, or engine out. Engine out I could manage - I’ve done that before, but transmission off without a ramp or pit is a pig of a job....

Any suggestions on what I investigate first?

Dunc

[Richard DAF Webmeister]

Hello,

"Shunting between forward and reverse with engine revving high" is akin to changing gear in a manual car without using the clutch.
As Andrew explains, when all is working correctly, the DAF/Volvo clutch is effectively engaged when the engine is revving above tickover. The mechanical "grunching sound" you probably heard, is painful to the ears. It's also painful for the car!

There's a few things that could have been going on. I think you mentioned that the car has not been used for a long time. Although this is a 66 and has a "plate-like" clutch, we have seen many times that on other DAFs that have the shoes, the combination of lack of use and rust, causes the shoes to jam in the clutch drum. But I digress. It could be that the linings on the clutch are shot.

The Volvoified version of the Variomatic, introduced a servo system to make the transmission appear "more normal" to owners who were used to other cars with automatic transmission. i.e. by having the "P/R/N/D lever..The servo is electronically controlled by the thumb button on the selector lever. If that is not connected of working, then it could be that the servo is not working, so not disengaging the clutch.

There must be a way of slowing the revs down. Have you really tried turning the screw adjusters on the carb?

Anyway this is all a starter. Hopefully others will appear soon to discuss.

Out of interest, what brought you to the wonderful world of Variomatics?!

[paull]

Hi Duncan,
Being also new to the variomatic Volvo - and enjoying it - I found the gear selector very different to any other automatic I’d driven.
Though mine is probably earlier as it hasn’t a park position on the selector so the following may not be accurate

The selector has a notched gate with a locking pin operated by the thumb button. The handle head has a switch in it that it actuated by the rocking of the head ( when the lever is against a stop)
If you push the lever forwards from drive with the button pressed you’ll end in neutral.
Push forward from neutral with the button pressed and the lever should stop - if you have the ignition on you should hear the electric clutch valve operate - release button and push forward further into gear.
Again from neutral to get drive push button in and move lever back to stop - clutch valve operates- release button and pull further back into gear.
Getting from gear to neutral is fairly easy but will need the button pressed at the right time.

Your carb sounds like it needs adjusting or has a blocked jet - possibly the idle circuit
Good luck paul

[andrew]

Hi Duncan,

Having thought about your car's engine I wonder if this might help: You've said it's revving too high and needs the choke to keep going, which suggests the mixture is too weak. There are a number of rubber pipes one of which runs from the inlet manifold to a double valve on the bulkhead and if might help if you disconnect this pipe at the manifold and block the opening on the manifold. This will eliminate any air leaks within the transmission system, which might be affecting the engine's running. With the engine switched OFF put the gear selector in neutral and leave it there until the tick-over is sorted out, as changing gear when the tick-over is too high sounds terrible and can cause serious damage to the transmission. You need to set the tick-over FIRST before progressing further. By the way, where is the car?

[starider]

This problem is often the large rubber pipe from the manifold

to the valve on the bulkhead,which could be loose on the pipe or disconnected/perished. This hose must be leak free.

[Dunc]

Thank you all - I’ve read all your posts and am donning my overalls and going out into the garage to investigate your suggestions. Yes the idling circuit does seem not to be providing enough juice to keep the thing running - I put new jubilee clips on every hose in the first place to get the thing running - there were no clips on anything! That did enable rough running to happen but as I have said, I can’t get the revs down. I’ll disconnect and plug a few hoses/connectors to isolate potential vacuum leaks and look at that ‘clutch’ device operated by the gear lever button. Will report back.

Thanks again for your help and suggestions - I am grateful. To questions posed; I am in west Dorset (Lyme Regis), And what brought me to variomatics? We generally muck about with Rootes cars but saw this in an auction and felt sorry for it.

[Dunc]

Update...... following advice from above I have got it running close to tickover now (still a bit ‘lumpy’) after chasing out a massive vacuum leak. The pipe coming off the inlet manifold leads to a 3-way union (plastic) mounted on the rocker cover. This union features a larger pipe which goes to the intake side of the carb and the third port on this plastic union carries a plastic ‘valve’ wrapped in a sort of plastic gauze/tape. So, spraying a bit of easy start around this when the engine was running brought revs up sharply so I guessed I’d found the culprit. On removal of this ‘thing’ which I imagined would be a non-return valve allowing excess pressure to dissipate (?), I found it was offering little or no restriction to air entering or leaving this little collection of vacuum pipes. I corked it up and the engine ran willingly and I put the choke all the way home and it continued to run, and finally I have been tinkering with the volume screw to try to achieve a nice idle. Any advice on the above would be appreciated - as in, what should that little valvy type thing actually be or do??

[andrew]

We're getting there......

What follows is an extremely condensed explanation of what happens with a Variomatic transmission, but it should give you some idea as to how things work.

The engine is a conventional 4 cylinder, of wet-liner design, built by Renault. The pipe at the back of the inlet manifold takes the vacuum and this is used to assist the pulleys to change "gear". The vacuum travels from the inlet manifold to the "valve thingy" (as you describe it) which directs the vacuum to the pulleys, as required. When the engine is ticking over the vacuum is not directed anywhere, but as the revs increase the vacuum is directed to assist the pulleys to "change up" to a higher ratio. If the accelerator pedal is floored (kick-down in automatic transmission) this vacuum change-up is stopped, allowing the transmission to change down, for quicker acceleration. In addition, when the brakes are applied the same electrical signal that lights the brake lights also reverses the vacuum, so that it helps the transmission change down, thus helping slow the car by engine braking and making sure the car's in a low ratio, ready to move off again.

So, the vacuum pipes, valves and connections are pretty important to a Daf (and Volvos!) If you haven't bought a copy of the workshop manual it would be a good investment, as would joining the club, as these things are often explained in greater detail in the club magazine, entitled "Belting Along".

I hope this helps (a bit!) and if you need more, just ask! 

[Richard DAF Webmeister]

Thanks Andrew for the plug!

Workshop manual is essential really - the actual factory one as opposed to, say, Haynes types, which are OK as far as they go, but the don't really go far enough.

Just an observation really.

[Dunc]

Yes I have joined the club, got a manual (ok it is the Haynes one which I know from my other cars is not great) And have received my first copy of Belting Along!

I don’t think we’re talking about the same vacuum pipe however. I think the pipe(s) you mention comes off one of the aluminium castings between carb and manifold - this pipe goes off to a 4-way split and does indeed seem to be very much part of the transmission vacuum system. The pipe I am querying is small in diameter, and comes off the top centre of the inlet manifold itself. As I say, it is smaller than the one which is connected to the transmission, and goes straight into a fitting which itself is fitted into the rocker cover like an engine breather. Oh my goodness I think that’s it - it’s the bloomin engine breather!!! This breather (if that’s what it is) has another pipe coming off which goes to the intake side of the carb AND it also has (or had) a little thing off to one side which looked like a non return valve but was infact basically just open to the air. This meant that the manifold could just suck as much air as it wanted straight through this funny little plastic breather/vent/valve. Makes sense now......it’s probably not standard....Well, thanks again to all of you for helping me work through that. Now that it’s running just about ok and idling at less than 1000rpm I will try engaging gears and driving tomorrow.....very very carefully.....

[andrew]

One of the pipes on the transmission valve should run to the air filter, as this allows the valve to admit atmospheric air (that's air with no pressure) to enter the pulleys at certain stages. At rest, when neither the accelerator nor the brake are depressed, the valve allows atmospheric air into all the cylinders in the transmission. As the car accelerates, the change-up side of the transmission has vacuum applied to it, and the change down is open to atmosphere, so the vacuum "sucks" the transmission to a higher ratio. When the brakes are applied the valve reverses this and applies vacuum to the change down side of the transmission and the change up side is open to atmosphere, so the vacuum "sucks" the transmission into a lower ratio. Therefore, as you can appreciate, there's a need for a pipe to feed atmospheric air into the valve.

[bobdisk]

Here is an article from a "Belting Along" of 2009 explaining the vacuum system. (I hope its ok to include it!) Cant remember who wrote it, but I think the author is a regular contributor to Belting Along.

Attachment Deleted