auto wont engage reverse

[Wornoutwoolclasser]

my 2004 patrol 4.8 petrol auto is slow to engage reverse. can take a few minutes. When it does engage it runs perfectly, just takes so long. Seems like a wire or switch or solenoid. Any hints

[Mike02Ti]

Any loose wires at the tcu in the passenger side kick panel?

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[threedogs]

when did you last have the Auto serviced???

[Turtle_au]

Slow to engage sounds more like a hydraulic issue.

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[Wornoutwoolclasser]

Thanks for the reply Mike02Ti
I jiggled all the wires like you suggested to no avail. It seemed like a good idea at the time. Alas
I took it to GV Autos who said it had coolant in the transmission.
I put a new radiator in it and i'll refill the trans after lunch
Think of me then
Cheers
John

[Wornoutwoolclasser]

Good question threedogs.
I have had it for 2 years and never had it serviced.
I took it to GV Autos who said it had coolant in the transmission.
Not good.

[Wornoutwoolclasser]

Thanks for the reply Turtle_au
Your diagnosis was close. Just not the hydraulic issue I was hoping for
A new radiator and fresh oil might fix it.
I'll find out this arfternoon

[happygu]

I have heard of a few 3 Litre Di Autos with the same Coolant in the Trans Fluid problem when the radiator gives up internally, and in most cases, the coolant kills the Auto.

I hope yours will be OK ..... if the plan is to keep the truck for a long time, it may be best to add a separate trans. cooler to keep the fluids totally separate, to prevent it happening again.

[Wornoutwoolclasser]

I have heard of a few 3 Litre Di Autos with the same Coolant in the Trans Fluid problem when the radiator gives up internally, and in most cases, the coolant kills the Auto.

I hope yours will be OK ..... if the plan is to keep the truck for a long time, it may be best to add a separate trans. cooler to keep the fluids totally separate, to prevent it happening again.

Thanks happygu.
I thought of that and decided that the radiator was probably well worn and a new one was $350.00. It was an easy fit, saved time and I could try it today.
New radiator, new coolant, new oil, same old problem. Auto knackered. Ah well

[mudnut]

So the filter accessed by taking the bottom sump tray off the auto was changed out as well?

EDIT, for futiure reference, the transmission runs a strainer not a filter.

[Wornoutwoolclasser]

Thanks mudnut. I don't think your RB30S is simple at all

I didn't change the filter and GV Autos didn't invoice me for one so your suggestion makes sense.
It wasn't too bad until last week when I got caught in loose sand at a beach towing the boat. After a lot of back/fwd we got it out but everything got a bit stressed (hot) and reverse engagement became much slower.
Forward engagement is still normal, gear changes are sweet, just slow to engage reverse.
I'll change the filter and let you know what happens

[NissanGQ4.2]

Possible worn reverse clutch plates, you won't really know until gearbox comes out :(

[mudnut]

There is a strainer in line before the oil pump. The correct sealant applied to the surface of the tray, not the gearbox surface, should take up any low spots between the surfaces and gasket. Since you have already changed out the fluid you should only need enough to refill the tray and a bit of a top up. I sincerely hope it works for you, but as suggested above, it really does sound like worn reverse clutch plates.

Edit, the transmission runs a strainer, not a filter.

[Wornoutwoolclasser]

If the plates are worn wouldn't it slip?

[BillsGU]

Autos are for experts. Go to the auto place on Thomas Mitchell drive Wodonga next time you are in town. Your problem may be an indicator of more serious problems that will leave you stuck in the middle of no where.

[Wornoutwoolclasser]

That's what I was afraid of. I suppose I'm clutching at straws

[BillsGU]

Nothing wrong with getting advice and finding it may be something simple and cheap. But when all the guessing is over - call in the experts. Sometimes to keep going costs more in the long term (recovery costs if you get stuck or by causing irreparable damage).

[mudnut]

What exactly did GV autos put on the invoice?

[Wornoutwoolclasser]

Nothing really because when they went to drop the oil they noticed the coolant ingress and rang to tell me the news. The radiator was the first thing that had to be replaced so there was no point in doing anything else until then. Now that I've done that I may as well change the filter and see what happens. if that doesn't fix it I'll have to get it rebuilt.
The only item they charged for was the oil to top it up.

[mudnut]

Must've been very minor contamination, as when coolant leaks into the auto (in my experiences) it usually overflows and you find a pool of
fluid /coolant under the vehicle. Did you notice the coolant level dropping, at all?

[Wornoutwoolclasser]

I wondered about that because the coolant bottle is always low but never empty. Underneath the car is spotless, not a leak anywhere.
One of my sons who rebuilds mining transmissions in Mt.Isa tells me that ethylene glycol is the component of coolant that dissolves the clutch plate linings yet I only use coolant that doesn't have ethylene glycol. I'm still clutching at straws I know but lets just see what a new filter does and take it from there.

[Wornoutwoolclasser]

Thanks mudnut. The filter isn't listed in the parts book and the dealer couldn't help at all.
I haven't had the sump off but the new oil has improved things considerably.
Its towed the boat 60kms every day since (1000kms) and launched and retrieved it so I'll give it a chance.
I still wonder why it doesn't slip if the clutch plate lining adhesive has been dissolved by the coolant as GV Autos suggested?

[mudnut]

I assumed that there would be a filter, so I looked deeper into it and found that on page AT 23 of the TB48 manual, there is a fluid path diagram, and it only shows an oil strainer, not a filter, so there you go. I learned something new too. Sorry I have wasted your time on that. Still, if it does play up, it may be worth checking that the strainer isn't partially blocked, with clutch plate material.

I have amended previous posts, for future reference.

[Wornoutwoolclasser]

Don't ever be sorry for trying to help, anyway times only wasted if nobody learns anything. I need all the help I can get at 64
How hard is it to get at the strainer?

[mudnut]

On a GQ it is just a matter of dropping the pan, and the strainer is one of the first components to get to. I am not gunna assume it is that simple on GU though.