MX-5 OC Forum

As my signature states I drive a 1990 Auto.

When cold it can, on occasion pause... I'm not explaining this well... I stop at a t-junction to turn left. Car idles perfectly well and normally. I accelerate to pull onto the road... Nothing happens, engine continues to build and then the car will jerk forward with a little wheel spin. Like I say, only when cold and it makes the first couple of minutes of driving slightly interesting. Gear changes can be very jerky but I figure thats the mk1 auto gear change.

Any ideas what could be causing the lag?

There are a few things which may be causing the `lag` and jerky gear changes such as sticky hydraulic valves, glazing on the brake bands within the gearbox or tired old over-heated transmission fluid. 

The good news is that all of these things can very often be easily cured by draining the old transmission fluid, flushing out all the tarnish and sludge build upand re-filling with fresh automatic transmission fluid (ATF of the correct grade) along with a dosage of the correct `Wynns automatic transmission treatment`

Should end up as good as new without lifting a spanner (apart from draining out the old crud)

Let us know how you get on with it?

Dr. Eunos

Thanks for the quick response. :)

You are dealing with a techie idiot so bear with me.

I thought if I drained the transmission fluid I then had to fit a new gasket? Or is this job even easier than that. :)

Normally auto-boxes have an oil sump with a drain plug, just drain out the fluid and replace the fluid and ATF treatment down the oversise gearbox dipstick tube, you need to be careful not to overfill, that can be just as bad as underfilling. Follow the workshop manual (available from Muppet as PDF here on the forum.....probably)

You may need to flush it a couple of times to ensure you have nice clean fresh fluid in the torque converter

Good luck, hope it cures your ills....

Dr. Eunos

Ok then.

And for my next really dense question....

Is the atf dipstick the one on the drivers side of the engine or the one on the passenger side? I have one with a yellow top and a very long dipstick which is on the passenger side ... I initially thought this was it due to the length more than anything but now on reflection I'm not sure. Apologies for my complete lack of knowledge. :) 

It will be the longer one as it needs to reach down into the gearbox fully

Awesome. Cheers buddy

 The roadster Auto does not have a drain plug, it is a real messy pian in the a*** to do.

M-m

Suck it out of the dipstick hole instead with a large syringe and some poly tubing?

Exactly what I planned to do. I have a syphon kit for engines.... But as I said, The oil looked fine and had no smell atached to it either. So I'm thinking shes just knocking on a bit and needs the extra tlc from wynns. Course it could be poor quality atf as well but there isn't anyway of telling that. Maybe when it gets warmer I will change it depending on how long the wynns treatment works. :)

Good, and really glad it has sorted you out, worth getting the old oil drained and flushing and adding the Wynns it really makes a huge difference to jerky and hesitant auto-boxes, I found out years ago after borrowing a Volvo estate to tow one of my old Rallycross cars 500miles to Lydden Hill and back and literally `cooked` the auto transmission fluid causing the shift valves to stick solid, ten mins after the Wynns it was all perfect again:

Ain't seen one of those volvos for a long time :)

Love the volvo - great old cars. could be recognised form a mile away as a Volvo-not like todays Eurobox variants from all the makers.(Sorry to go off topic) I was a keen Rallycross fan in those days and before - The era of Tony Bardy, Gollop and Shankerand there was a Greek driver in an Audi Quatro? - My friend raced a Mini at the time ,I remember a 911 porsche burning out at RAF lynham -very sad. We used to visit John Cross at his Rally cross shop -Autocross.

teaser56:

Love the volvo - great old cars. could be recognised form a mile away as a Volvo-not like todays Eurobox variants from all the makers.(Sorry to go off topic) I was a keen Rallycross fan in those days and before - The era of Tony Bardy, Gollop and Shankerand there was a Greek driver in an Audi Quatro? - My friend raced a Mini at the time ,I remember a 911 porsche burning out at RAF lynham -very sad. We used to visit John Cross at his Rally cross shop -Autocross.

DIMI MAVAROPOLAS ???? perhapes.