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Help! No reverse, wheels locked


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Good evening everyone, reaching the end of a long restoration on my 1959 tr3a, I went for my maiden drive today, and all things considered not bad.

bit more air to come out of the brakes me thinks, throttle sticks, oh dear the carpet is in the way, that aside it went well, and frankly seems much more refined than my 1954 TR2. However once home I noticed there is a large oil leak from the gearbox area, this appears to be where the solenoid housing joins the side of the overdrive, ok I'll add it to the snag list. I hasten to add, that although the solenoid clicks the overdrive doesn't work.

worse is to come however, as now just manoeuvring the car in front of my garage, it won't go backwards! If I jack up the rear end, with one wheel off the ground, the other won't go rear Wards! Both off the ground and they will rotate, the other going opposite to the one turned.

 

whats gone wrong, I've heard somewhere that the overdrive can lock, so I won't force anything as reverse gear does engage, but it is locked, any ideas?

 

regards Bob.

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It does sound as if somehow, the o/drive has engaged, and perhaps stuck in that mode, Bob.

In which case, it is a good idea not to do any more reversing... until you're certain that o/d is disengaged. 

With a bit of luck, there'll be no harm done. Over the years, l've done this a few times, and have got away with it.

Tim.

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Yes, your overdrive is apparently locked. If it's a mechanical faut, the only solution is to remove the drive shaft if you need to move the car back ward.

 

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Bob

yiu are correct in your suspicions that the od can lock and you are very right not to force it  

 

it could be the switches on the box not protecting you from operating the od in reverse  

do nothing until better advice than I can give comes along

h

 

  

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Could be overdrive stuck in.If you manage to reverse with it stuck in you will wreck the overdrive. Put it on axle stands and try to see if the solenoid is working.When you have found the problem you can then run the engine in gear and try the overdrive to see if it works properly. Speedo will rise when overdrive is engaged.

Regards Harry

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If you are certain that the electrics are not keeping the overdrive engaged, then a hefty wallop (or two) on the overdrive's casing with a wooden mallet (or copper-faced hammer as used for wire wheels) might persuade the overdrive to disengage itself.

As stated above, do NOT NOT NOT attempt to drive the car backwards as you would likely split the overdrive's casing.  If you must move the car, disconnect prop shaft, or put a trolley jack under the differential and lift both rear wheels off the ground.

Good luck!

Ian Cornish

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Thanks for comments thus far everyone, I have unbolted the propshaft to enable pushing the car where I need it, basically out of the way of the front of my garage so I can get the up and over door down!

The solenoid is drawing power as indicated by noise and the ammeter flicking. Reassuringly perhaps it will only do this in second third and top gears, not first or reverse. That said I think the overdrive may just be on all the time. When driving about today for the first time, it seemed much higher geared than my tr2. Something occurred as I reversed out of my drive onto the road, but once back can't move in reverse as reported.

the overdrive, and indeed gearbox with engine were restored by a very well known tr restoration company, that said it was 10 years ago, I brought the car 3 years ago as an abandoned project, a huge meccano kit if you will.

so huge oil leak from overdrive, and it is maybe stuck in engaged mode, any suggestions as to course of action?

 

Regards Bob.

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Hello there,

I'm no specialist in O/Ds but:

1) the solenoid operates a lever, this lever opens a hydraulic pipe, and IF there is oil pressure within the O/D THEN the gears are moved and the O/D engages

2) oil pressure is built up by a cam mounted on the gearbox main shaft (which happens to be the input shaft for the O/D). Plus you need a certain amount of oil to move the gears.
So the faster this main shaft rotates, the more oil is pumped and the faster the O/D engages. This is why many O/Ds engage faster the faster you drive !

3) so at a stand still, there is no oil pressure and O/D disengages typically

What I do not know is: What happens if the solenoid/ lever ist stuck and the oil pressure can't be reduced/ reliefed - in this case, if the system is leck-tight - the pressure will stay high and the O/D stays engaged. 

 

Regarding the solenoid: If activated, it draws a very large current (10amps?) until its plunger moves. Then - at the top of its movement, there is a small switch inside, which is activated and the power of the solenoid is reduced. A very nice little electro-mechanical trick with one draw-back: IF this switch does not work or if the top position is not reached to activate the switch then the amount of power inside the coil will destroyed this solenoid within minutes.

So be careful when examining the whole unit - keep an eye on the solenoid….

 

I would remove the solenoid anyway and then try to move the lever "down" to its "disengaged"-position. If the O/D stays engaged, then removed because something mechanical might be wrong inside.

 

Regards & good luck, Johannes

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Clean off the overdrive and see if you can locate the source of the leak.  I don't want to be a doom-monger, but if the leak from the overdrive really is massive, then it is possible that the casing cracked when you attempted to reverse the car.

Ian Cornish

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Hi everyone,

 

Many thanks for the replies so far, I thought I would update with progress so far, and perhaps obtain more advice given what is now known.

I have removed the gearbox tunnel, which has revealed that the od operating lever cannot be moved with the hand.

The solenoid mounting plate has split, there is a gap of 5 maybe 6mm on the back edge lower down. No wonder there was a large oil leak, I suspect that all oil has now run out, as it continued to weep when parked up.

Although the solenoid can be seen attempting to move the operating lever, this only occurs in 2nd,3rd and 4th gears, which electrically I find reassuring. The solenoid smells burnt, I suspect one of the coils may have overheated/failed.

Initially I have ordered a replacement mounting plate, solenoid and associated O rings and gaskets.

I will this afternoon remove the plate, Spring etc and hope no nasties are inside. Assuming not, my plan is to replace the mounting plate and adjust the solenoid correctly, something I initially didn't do, just checked the solenoid was working the operating lever.

So, here's the question, could all of this be because the solenoid was incorrectly adjusted, and I attempted, albeit gently, reversing with the overdrive on.

Regards Bob.

 

 

 

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Hi Bob,

                I fear that you have seriously damaged the inside somehow.

Whatever broke the mounting plate imparted a great deal of force into it. All the forces spin around and go out the back end.

Anything escaping sideways is a catastrophe in the making.

Consider getting it sorted by a reputable workshop

 

Roger

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  • 4 weeks later...

Thought I’d give an update, if only to help others in the future. I took the gearbox and overdrive out of the car, then separated them.

within ten minutes established that:

the operating valve is bent, the accumulator piston is stuck, the two metal strips holding in the operating pistons have both been bent, a large circlip, now in two pieces, dropped out. Finally, there was bronze coloured filings in the residual oil.

Put all that together with the split solenoid mounting bracket, and something very bad has occurred......  I spoke with Dave at Overdrive spares in Rugby, who had seen all this before. Apparently if an overdrive is overhauled and then not used, or stored dry for a long time, mine was in excess of ten years, this can happen. The accumulator sticks, the clutches stick in the engaged position, the pressure continues to build, sometimes to well over 1000 psi. The weak point, before the casing splits, is the solenoid mounting bracket.....thankfully. Dave says that for some competition use pressure up to around 700 is not unheard of, but in my case whether the solenoid was energised or not, once switched in, however briefly, it stayed there.

i took the overdrive to him, and now have it back, repaired, checked and adjusted. I just need to summon the motivation and get it back in the car!

regards Bob.

 

 

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Bob. 

What a nightmare. Glad you have it sorted. 

Just refitted mine after a full rebuild and I don’t envy you your task. 

But satisfying when it’s sorted.

H

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