Intermittent a type overdrive.

[Blue cedar]

Took the '6' out for it's first run for a few months. Previously, overdrive has always been fantastic...no issues. Today, after a few miles I was driving about 70 in overdrive and it felt like the engine was miss firing, but realized it was the overdrive kicking in and out. For rest of my trip, 10 miles or so, sometimes for periods it worked as I tested it by switching it in and out. Then for periods it wouldn't engage.

 

Am I right to assume it is an electrical fault ? Should I hear a click when engaging or disengaging ? Can I test the electrics by putting the can in 2nd, with the ignition on, whilst stationary and engine not running ?

 

Appreciate any guidance .

[Mike C]

I'd test with the ignition on and the engine not running, gears in 4th engage the overdrive. You should hear a click from the relay on the passenger side of the engine bay and from the solenoid on the passenger side of the gearbox.

[WWT338J]

Worth checking the oil level in the gearbox.

David

[BlueTR3A-5EKT]

as above

 

Peter W

Edited July 2, 2017 by BlueTR3A-5EKT

[Ur1328]

Could be dirty points on the solenoid! It happened to me only two months ago.

[RogerH]

Hi Peter,

all as above -

put in 4th gear

Ignition ON

Engine - NOT running

Select OD NOTE do you use a 'logic box'

There should be a soft click from the relay

Followed immediately by a louder clunk from the solenoid.

 

Try this repeatedly and at the same time gently move the gearstick, rubber gaiter, as much of the loom as you can get at and OD column switch -

does it drop out with any movement.

 

If all OK

Check oil level

 

That's the easy stuff.

 

Roger

[alec]

I had this problem on my 74 TR6

It was a corroded loose connection on the solenoid.

Original push on crimp lug was replaced but had done well for 40 years

[Bill Bourne]

Hi Peter

 

I also had this issue a while back. The problem turned out to be that the overdrive switches on top of the gearbox were not engaging properly with the spring ball at the bottom of the switch due wear and tear. If I remember correctly, the solution was straight forward by replacing the fibre washers using slight thinner ones so that the switch would engage properly.. Or of course, just replace the switche/s. Straightforward !! ?? well after you have taken the tunnel cover off.

 

Good luck

best bill

[Blue cedar]

Findings: when operating the o/d stalk.....job delegated to her in doors....

- there is a strong clicking sound from the relay ( passenger side, upper inner wing .....engine bay)

- listening from under the o/d unit, no noise coming from the solenoid ( passenger side of o/d unit).

 

What should I do next ?

 

On a side note, the solenoid has a grey thin rubber boot which has split. Is this significant ?

[Blue cedar]

Struggling to find the source of the problem, hope someone can help, please.

 

Looked at the buckeye site...outstanding.......as my reference to overdrive faults.

 

I believe the fault is the supply of volts to the relay via the brown wire connecting to the (terminal c1) relay. It only registers 2 volts, rather than 12 volts. I have traced this brown wire back to the fuse box. There is only 2 volts coming off the fuse box terminal.....and another brown wire then feeds to the fuse box which I believe should also supply 12 volts , but does only supply 2 volts.....I can trace this brown wire back to a block connector, ( on the inner wheel arch).

 

The supply into the block ( another brown wire) only delivers 2 volts.....so my challenge is in tracing this wire back towards the 12 volt supply, as I am assuming that eventually by tracing back the wire , I'll eventually find 12 volts reducing to 2 volts ( the fault).

 

So continuing to trace back the wire gets lost in the bunch of wires bound in black tape and I can not trace back without removing all the black tape and making a mess.....can anyone advise the next point this brown wire shows its self . Perhaps, there I'll find a feed wire in showing 12 volts and 2 volts out.

 

Help will be much appreciated.

[ken foster]

Took the '6' out for it's first run for a few months. Previously, overdrive has always been fantastic...no issues. Today, after a few miles I was driving about 70 in overdrive and it felt like the engine was miss firing, but realized it was the overdrive kicking in and out. For rest of my trip, 10 miles or so, sometimes for periods it worked as I tested it by switching it in and out. Then for periods it wouldn't engage.

 

Am I right to assume it is an electrical fault ? Should I hear a click when engaging or disengaging ? Can I test the electrics by putting the can in 2nd, with the ignition on, whilst stationary and engine not running ?

 

Appreciate any guidance .

I did all the above last year. The oil was low so not a completely wasted exercise. Mine stopped working out on the road....... The cause???? My big left foot had pulled the bullet connector out by the dip switch.

ken

[Blue cedar]

Ken, I've removed the g.box tunnel. All is fine at this end.......my challenge is tracing back this brown wire, to find the point where the 12v reduces to 2v.....

[Motorsport Mickey]

Peter,

 

You may find responses are much reduced for the next couple of days, it's the International Weekend event at Malvern and many of the regular Forum posters will be attending and on their way there today.

On the other hand if you attend at Malvern with your car you will find unparalleled expertise available to help diagnose and cure it, otherwise it may be Monday before normal service is resumed.

 

Mick Richards

[Mike C]

My wiring was originally a mess ( someone had rewired it to bypass all the gearbox interlocks) and I haven't looked at this for a while, but the wiring diagrams show that brown wire going to the positive terminal on the starter. If the brown wire's still there I'd check its terminal is clean and tight. 2 volts looks like the power feed may not be coming to the brown wire directly from the battery.

Edited July 7, 2017 by Mike C

[Blue cedar]

Back to report back with a smile on my face !

Turned out to be a dirty and loose connection at the starter. I've got a full 12 volts at C1 feed onto the relay and a lovely click from the solenoid.

 

I'll leave the refit of the gearbox tunnel until tomorrow.

 

Thanks for pointing me in the right direction, Mike..

[Mike Atwell]

Today my TR6 (CR model) has developed a problem with the overdrive (J type). The OD does not stay in one mode or the other, but, switches between normal and OD without touching the switch.

Any suggestions are welcome.

[RogerH]

Hi Mike,

have you got an OD logic box fitted ?

 

Otherwise, is it only in 4th gear or does it do it also in 3rd.

If only 4th then the inhibit switch on the GB top cover may need half a turn into the box.

 

Roger

[Mike Atwell]

Hi Roger

 

Thanks for reply

 

Does it in 3rd and 4th.

 

Dont know what a logic box is

[RogerH]

Hi Mike,

if you don;t know what a logic box is then you haven't got one'

 

3rd and 4th use the same inhibit switch.

It may be that the switch needs to be screwed in 1/4 or 1/2 a turn.

Or the switch itself could be failing.

 

Fit a new one.

 

It could also be 1001 other things but the switch is easy

 

Roger.

[Mike Atwell]

Thanks Roger.

 

When I tried yesterday with engine not running, gearbox in 4th, ignition on, at first i could not hear any click from the solenoid. I checked the wires on the fuse box and a double purple on the output side was loose. I refitted it and can now hear the click. Was not able to try car yesterday, but hoping to do so this afternoon. Will come back with result.

[Steves_TR6]

On the subject of the j type overdrive, mine works perfectly in 4th but is slow/reluctant to engage in 3rd when hot.

 

I assumed there were separate switches on the gearbox for 3rd and 4th, but Roger says otherwise ( and Roger is always right!).

 

Thoughts?

 

Steve

[RogerH]

Hi Mike,

the purple wires should not affect the OD.

 

However the Green wires are close by and so you may have disturbed them. (green feeds the OD)

 

Remove the green connectors and give them a good clean.

 

http://www.advanceautowire.com/tr2506.pdf

 

Roger

[Mike Atwell]

Hi Roger, Managed to get the car out yesterday. The OD is not working at all now. I guess i will have to check the inhibitor switch and the solenoid. BTW, I cannot find the relay on the inner left wing there is one relay not two as I see in the pictures

Edited September 28, 2017 by Mike Atwell

[peejay4A]

Iirc the J type doesnt have a relay because it's a different solenoid to the A type.

[AndrewP]

Sounds like a similar issue I had with the J type on my sprint..ended up being a combination of old gearbox oil and putting new O-rings in the solenoid and the 3 removable plugs in the bottom of the overdrive.

If it's dropping in and out without the solenoid moving then it's more think likely pressure (or lack of) that's causing the OD to drop in and out.

 

The buckeye website it good for details on this..

 

Cheers