Auto gearbox oil

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davidg
Posts: 1
Joined: Fri Oct 09, 2020 11:00 am
Forename: David
Surname: Girvin

Auto gearbox oil

Post by davidg » Sat Oct 10, 2020 6:06 pm

I have to remove the sump of my auto gearbox on my 71 GT as the gasket is "weeping" oil and leaving its mark everywhere I go!!
The recommended oil according to Haynes is ATF to BLMC type F or Duckams Q-Matic. Can anyone advise me of an easily available alternative?

Many thanks

David

ChargedAutoGT
Posts: 53
Joined: Wed Nov 21, 2018 9:37 pm
Forename: Graham
Surname: Moore

Re: Auto gearbox oil

Post by ChargedAutoGT » Tue Oct 13, 2020 9:33 pm

You need to use TQF. I buy Castrol.

Unfortunately on the pricey side compared to cheaper ATF fluids (available MGOC, Opie oils and I guess others) but the information I have read, from several sources says that the standard type of ATF fluids nowadays can/will(?) degrade internal seals. In the greater scheme of things, preservation is better than fixing stuff and £100 (price per fill) doesn't go far nowadays so an investment I am prepared to make.

I change mine every 2 years. I drive about 3-4k miles per year but oils degrades with age as well as use. Now you do have to be careful as the torque convertor holds quite a bit, so when you empty the sump it's a good idea to measure how much came out as I always find that when the fluid is new and clean, it's very difficult to see a line on the dipstick. The measuring procedure is to warm the engine, stop, and then put it in all gears to slosh it around, then dip. I do put a tiny dusting of talc or similar on the stick to make it visible.

One sign of not enough fluid is no drive in 3rd. I found this after not being able to read the level properly, and not putting quite enough in. They say too much can be damaging, but not sure how, apart from a mess.

But I am very pleased to have found another auto driver as I do have a question or two for you please. There must be a few of us as I have seen a couple of dozen cars sold. My auto box drives ok, but I do suspect (like the rest of my car) that maintenance by previous owners has been patchy, if at all. One of my first jobs 5 years ago when I bought the car, was to change the auto fluid, what came out was almost black! After a couple of changes (and taking the engine out to refurb it) the fluid is now a red colour always. But I have never removed the gearbox.

I know that the tension of the kickdown is responsible for the speed at which the box changes up & down and I have no issues there. I have actually changed it quite a bit over last few years as I built and installed a supercharger of my own.

BUT...my question relates to the immediacy with which the box changes in response to a forced change with the gearstick. I drive mine like a clutchless manual. So I use the 2 & D all the time. Much less so 1st.

So say for example, a 'racing' start' So into 1st (or second) and floor it. Once i hit about 4500 or 5000 I want to change up. But when I do, the box always seems to take a second or two to change. Likewise, using the drop from 3 to 2 (again with the stick) to achieve engine braking, say coming from dual carriageway to slip road, I always find the delay.

Now I would understand that if the target gear were incompatible with the RPM and gearing but that is not necessarily the case. And if it were I would expect the box to hesitate.

There isn't but real user info/diagnosis on our boxes anymore and whilst the BL workshop manual (and others from Volvo etc) are available and do have good troubleshooting guides - this is one point that is never mentioned.

Now some may suggest to live with it, and I may. But I am thinking of doing one last engine pull (with Gbox this time) to get the box refurbed. On the rolling road the operator did say that whilst the clutches were great (and better than he expected) at mid to high rpm, there was a bit of slippage low down. Not that I have noticed on the rodd but he could not hold the speed constant. If I don't do it soon, then I will be past crawling under the car and I have found someone fairly local who can do it. An ex Borg Warner man. I am wondering if it really needs a darn good cleaning as I really suspect it may never have been out of the car.

So I would be really keen to hear of your own experiences.

Many thanks, G

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