At gearbox at the twlight of its days...

R

Rovertron

Member
In the rare chances I've got my '69 3500 Auto out this summer, I've had a couple of odd noises I think from the gearbox.

The first time it happened was parking up on a moderately steep incline. I was backing the car up when I got a loud noise from what I think was the gearbox. It sounded like something was fouling, a loud "click-click-click" sound. It was certainly jarring enough to panic me and I'm not easily flapped.

I backed the car up in the neutral, parked it. When I got back, I very gingerly nursed the car home at first and it was absolutely fine. I put it down to one of those things. I checked fluids, cables, etc, etc - all fine.

I've used it a fair bit since, mainly several 15 mile round trips to collect stuff rather than use my daily car. Not a problem with it. The kickdown works perfectly, it selects gears more or less in the right places. I admit the gearbox has never been right on the money ever but I've put this down to the fact it leaks, it needs topping up, it needs a little kickdown adjustment here and there. It's 43 years old. In colder weather, it does have habit of not making the jump from '2' to '3' requiring me to manually intervene. It's always been something of an 'odd' box.

Anyway, I had it out for a good run on Friday and I was quite some way from home and the noise happened again, this time combined with a definite loss of power. Luckily the road was quiet and I pulled over. I figured as it was D3, I would start by locking the gearbox in '2' and nurse it home. It was a good 10+ miles home and it made it fine.

I got it home and took a warm reading and it wasn't low on fluid (the dipstick though is a habitual liar). The fluid didn't smell burnt but it wasn't quite its usual colour, although further readings did see an improvement in the colour. I popped it back in D3 and did a mile or so circuit around home, including some inclines and it was fine.

So I am stumped. Truth be told, if it had only done this whilst driving, I would have thought it was a binding caliper but it made this noise stationary too.

As for the model of gearbox, it's definitely a 35 (I had the filter gun and seal replaced) but I'm not sure on spec. The selector is 1, 2, D3, N, R, P. There is no D2 available, 1 and 2 are single selections. There's a full throttle kickdown which works just fine but I've had to make a couple of adjustments in recent years.

It's possible the fluid has been allowed to get too low (I have no faith in that dipstick) but I admit I wouldn't be surprised if the box is on the way out, I had a chemical test done on the fluid last year and it came back fine but I've never had much confidence in it ever since I've owned it.

Could anyone shed any light on this one? I admit a new gearbox would hurt financially but it's getting to the point where peace of mind counts for more.
 
Rovertron said:
The first time it happened was parking up on a moderately steep incline. I was backing the car up when I got a loud noise from what I think was the gearbox. It sounded like something was fouling, a loud "click-click-click" sound. It was certainly jarring enough to panic me and I'm not easily flapped.
Click to expand...

I'd say that sounds more like the diff pinion mounting has collapsed, and that noise was the prop bolts fouling on the crossmember.
 
Rovertron said:
So I am stumped. Truth be told, if it had only done this whilst driving, I would have thought it was a binding caliper but it made this noise stationary too.

As for the model of gearbox, it's definitely a 35 (I had the filter gun and seal replaced) but I'm not sure on spec. The selector is 1, 2, D3, N, R, P. There is no D2 available, 1 and 2 are single selections.
Click to expand...

If it makes the noise when stationary in "P" or "N" that limits it to the converter or front pump, or the filter noisy, nothing much else is engaged or moving inside, and what is isn't under load. If it's when in gear but not moving the cause would vary according to which gear, and I'd expect you to be experiencing other problems, not just noise.

If it's a PRND21 box, "D" is Fully Auto, "2" is SECOND gear only, and "1" is FIRST gear only. (Providing it is a proper Rover spec box.)
 
Hi Harvey,

Thanks for your thoughts. I don't think I was all that clear, as I pulled up to reverse, the car was stationary on the incline, the gearbox in 'D' and the car made this terrible racket. So I killed the engine, reverse parked it in 'N' with the engine off. As I went to leave, engine started and in 'D' it was absolutely fine for another hundred or so miles.

Driving at around 25-30mph it happened again in 'D', very similar noise only this time with a loss of power (hence my thoughts towards the gearbox).

I nursed the car home in '2' and once home, checked the levels in the box (which looked ok) and then drove it around in D3 again - absolutely fine.

I've had the misfortune to have the diff loose before (not my fault I add :) ) and that was accompanied by a lot of shunting from the box which simply doesn't happen. I'll have a look around there for any signs of scuffs or fouling.

You are absolutely right on the selector, it's PRND21, there's no lock-up, D2, etc, etc.

I think the only non-mechanical explanation could be an insufficient amount of ATF as I suspect my measurements are hopeless. Other than that, I don't know one component in a auto box from another being honest.

Thanks again and hope this helps.
 
If you're uncertain of the fluid level, then get that correct before doing anything else. See the sticky at the top of the section.
It's difficult to diagnose noises without hearing them, but in "D" but not moving, the noise could be slip or squawk on the front clutch set, the converter, or the pump, and I say in that order of probability, but you'd get slip or squawk under acceleration all the time. If you then got the same thing at 25-30 mph with a loss of power, I'd want clarification of "loss of power". If you mean an increase in rpm without an increase in roadspeed, ie slip, then that's a clutch fault, if you mean that the engine actually appears not to be able to power the car, as though something was actually grabbing it and slowing it down, I'd say that was converter. But they're only guesses, and tbh they will never be anything more with something like this, without hearing and driving it.
 
Only to add... thinking some more about it, it sounded as if the noise was coming from the front of the car.... I had my window open....
 
Rovertron said:
Only to add... thinking some more about it, it sounded as if the noise was coming from the front of the car.... I had my window open....
Click to expand...

In that case my recommendation would be to close the window..... :LOL:

But the converter is at the front. (Of the gearbox).

All you can do really, once you have the level correct, is use it, and wait to see what the outcome is. The longer it goes on, the easier the final diagnosis will be.
 
Wow, quick reply. Thanks too for your thoughts and another opinion is always valuable.

Yeah, I was somewhat hassled on my return home so I'll put the good weather to use and give it a proper check using the sticky. From that, I'll post something up. My independent garage are very good at this kind of thing so I might ask for another chemical test and inspection.

In terms of loss of power, it was as if divine intervention made the engine vanish leaving only a dreadful sound in its place.

It is really hard to describe but in the words of Sherlock himself, once you have discounted the impossible and all that.....

:D Having just seen your other comment, I think we have a suspect area to start on.

Thank you.
 
I checked the gearbox fluid levels using the sticky (warm engine on, full run through selection). Cleaning the dipstick, there's no lamination or any sign of varnishing or emulsion. Using white kitchen towel, the fluid had lost some colour but still smelled sweet not burned so I topped it up (probably less than half a pint) and it read just over high.

I have been out for about 20-odd miles including some steep declines and inclines (1 in 7) and not a peep other than some reluctant 3rd upchange which is 'normal' for the box. On the whole, it behaved as it always has and it is one that prefers to be slightly overfilled and the higher pressure that affords. I can't help thinking the bands are just old, how close to end of life I don't know.

Again, I am at a loss, all the upchanges (10mph for 2, 30mph for 3) were close enough for my liking, the car moves slowly without throttle in R.

Finally, I don't think I'm going to get piece of mind without some inspection work so I think I shall be consulting my flexible friend in due course.
 
Rovertron said:
it behaved as it always has and it is one that prefers to be slightly overfilled and the higher pressure that affords.
Click to expand...


Being overfilled won't increase the pressures, it just means it's slightly overfilled, so any leaks will take longer to show any ill effects. I'd be inclined to use it, and only get involved further once you have definite faults that need fixing. At the moment it sounds as though you are happy enough with the way it operates.

The only thing I can think of that could make an even slightly underfilled box give problems is an early filter fitted to a late valve block.
 
Thanks again for your thoughts.

I did change the filter and opted for a gun type which I did asked the garage to double-check on fit. There's just too much fluid to drain for a domestic change. It did reduce that all-too familiar whining noise, I was told the old filter was a bit of a state which might point to abuse at some point in its 43 year life to date.

In short, I just know precious little about the box from the previous owner who reported no problems but I even doubt that the correct dipstick is fitted.

I'll definitely plod on and I think a once-over from the local garage would put my mind at rest.
 
Rovertron said:
but I even doubt that the correct dipstick is fitted.
Click to expand...

If you read the book it specifically mentions the correct use of different lengths of dipstick, and matching tubes, with all the relevent measurements.
 
Rovertron, Harvey is being very modest here. The chances of a local mechanic, however competent on classics, being able to open up a Borg Warner and make a competent job of overhauling it - especially if there was anything incorrect in there that needed to be first spotted and then restored to standard spec, are ZERO!

Not counting Harvey - who you have to talk exremely nicely to to get him to actually work on a car these days, there are only two garages in the country I'd consider taking a BW to. One of them is a mate of Harvey's, the other is not the one most people would assume, and I'd still only go there after talking it over with Harvey!

Chris
 
Thanks Harvey, I didn't know that so I'll have a good rummage through my workshop manual and at least get that one sorted.
 
Just an update really.... well, the gearbox finally gave out with a real loss of power and reverse slipping really badly. It seems at first diagnosis that the torque converter is toast. I'm looking at a rebuild of the box basically.

Any thoughts on this? Should I get someone to rebuild it and refit or go for an exchange unit and fit that?... choices... choices......
 
Rovertron said:
well, the gearbox finally gave out with a real loss of power and reverse slipping really badly.
Click to expand...

Is the problem with REVERSE only, or TOP and REVERSE? REVERSE only is rear band, TOP and REVERSE is rear clutch.

Rovertron said:
It seems at first diagnosis that the torque converter is toast.
Click to expand...

What brings you to that conclusion? If the converter is seized they do cause a loss of power, but often that shows itself when revving up at a standstill, so much so that it's not even worth trying to drive them. Loss of power is most commonly an engine tuning problem.


Rovertron said:
I'm looking at a rebuild of the box basically.
Click to expand...

Not necessarily, it depends on your answer to my first reply.


Rovertron said:
Any thoughts on this? Should I get someone to rebuild it and refit or go for an exchange unit and fit that?... choices... choices......
Click to expand...

Exchange units tend to be built down to a low price rather than up to a high standard. If you get someone to rebuild your box, you need to find someone who knows what they're doing, and who you can trust to be honest with you. If you can manage that, then I'd say that was the better option.
 
As always thanks Harvey for taking the trouble to add your thoughts. I got a few more details over the last week or so.

The first diagnosis was that box was slipping pulling away from stationary and the converter was no good. They used their rolling road and applied reverse and then drive, the box was slipping badly in both cases.

The garage are very competent, having been in business for over 50 years and they maintain both older and newer cars. They have passed the box onto a reputable and well known rebuilder that they have used for years.

The next piece of information from the rebuild firm makes perfect sense, the rear clutch is also suspect too so I have asked for a full rebuild. I do know the rebuild firm as I used to live close to them and the previous garage that looked after my car also used them.

Incidentally, they also found a serious fault with the water pump and some play in the bearings, so much play that the grinding noise I experienced could have been the heavy S1 metallic rad fan clipping the vanes of the rad. So a re-cored rad and new water pump have been fitted to. As if that wasn't bad enough, the in-board rear brakes seem to be inefficient too. It never rains.........

Needless to say, I'm somewhat mortified that I let some components get so bad. Having a car like this and a young family don't really mix - they'll seize the keys though from my cold dead hands :)
 
You must log in or register to reply here.
Back
Top