MK4 Cortina, Ford C3 Automatic oil change

[mk4savage 62]

I'm thinking about changing the oil on my C3 Auto box on my MK4. Engine is a 2.8 V6. I know there's a filter on the underside and myself and a mate replaced it some 18 years ago when the gearbox was out of the car. I can't really remember what sort of job it was to do. At the time I relied on my mate as he'd done a bit of messing about with autos. Is it much of a job to do from underneath the car ? 

 

I'm guessing I won't get all the oil out of the converter so is it worth the hassle do you think ?

 

The other option I have is I have another gearbox to fit supposedly in working order and only removed for a manual conversion. 

 

The gearbox that is currently in was from a Granada, roughly 1985. It's definitely a later box than what should be in the car. Unknown mileage etc etc. it's worked ok for 18 years but I feel it could be getting a bit tired. The other one I have is from a 79 MK5. 

 

I did a couple of checks today as it clunks when engaging drive. There's slight play in the rear axle when the prop is rotated by hand back and forth. No movement up or down or left to right at the flange but with one wheel on the ground and one in the air there's play when the wheel is rotated back and forth. Not sure if that's normal or not. The noise may be coming from the gearbox. The rest of the prop seemed ok. 

 

Not sure if I should bother changing the oil if I can't drain it all out. What do you think ? Also, where's the best place to get the gasket and filter from ? I've seen some on the old eBay but not sure of the quality. Someone here might know of better quality parts out there. 

 

Cheers

[sheffieldcortinacentre 726]

For what it will cost you might as well be do it. Large container undo sump bolts lowering rear end to let the blood bath commence then if I recall it's one bolt holds filter.

Longest part will be refilling.

[John Mack 327]

You could dump the oil and refill then run it for a few hundred miles then do oil (again) and filter, like you I'd want to know I was changing as much of the oil as possible.

 

I'd be changing the oil before the gearbox, then take it from there.

[mk4savage 62]

Thanks guys for the replies 👍

 

I've been out in it today and I've found that when it's hot it seems to 'Snatch' as it changes down from 3rd to 2nd. I've had this before on the original C3 that was in the car. This one has only recently started doing it. 

 

I've also got wear on the rear axle I'm fairly certain. If I ease off then back on the accelerator quickly there's some noise (clunk) coming from the rear. The axle has done 62,000 miles. It isn't noisy or whining but I've noticed a slight noise when cornering to the right which I think points to a wheel bearing ?  Not bad though. 

 

Otherwise it goes like stink and seems to keep pulling when you give it some welly. I don't think the box is slipping. 

 

I'll go with an oil change I think then as you say John, change it again after a few miles. Probably be 12 months between changes as I don't use it much. 

 

Craig, it's a shame they didn't fit a drain plug in the oil pan. Would make life a bit easier 😭 I guess I'll be up to my armpits in transmission fluid. 

 

 

[sheffieldcortinacentre 726]

I've modded a few over the years by fitting a drain plug.

[mk4savage 62]

It would help to get the oil out first before removing the pan. What a mess it'll be 🤬

[John Mack 327]

9 hours ago, mk4savage said:

It would help to get the oil out first before removing the pan. What a mess it'll be 🤬

 

Something like this might do the job, I'm thinking something like screenwash tubing would fit down the dipstick tube ?

Sealey AK54 Oil Suction Syringe 550ml Clear Body Easily remove oil Gearbox Diff 5054511210798 | eBay

[mk4savage 62]

Yes. I suddenly remembered earlier today, I've used one before on this gearbox. I think I had put a drop too much in and I sucked a bit out using one of those. Not mine, belonged to a friend. I don't know why I didn't think of it before. I'll see if he still has it before buying one. 

 

This one was more like the tool I used but the same idea.

 

Thank you for the link and the suggestion 

Edited April 1, 2024 by mk4savage

[mk4savage 62]

Following on. Can anybody recommend the correct fluid for this gearbox please ? 

The dipstick top is red coloured as opposed to black but all the ATF fluid I keep coming across seems to be for Borg Warner boxes. 

 

This is the info out of the Granada Haynes manual 

All the oil I looked at seems to match that earlier spec. 

 

Cheers all

 

Edited May 18, 2025 by mk4savage

[sheffieldcortinacentre 726]

I just ask for the red stuff for fords.

The Borg Warner used the same stuff as the ford C3

[mk4savage 62]

Cheers Craig.

 

I was a bit confused as the early dipstick is black and the later one is red. Not sure my local motor factors will have a clue. All the decent ones have packed up.

 

Imagine walking in to Eurocarparts and asking them for gearbox fluid for a Cortina 

 

Do you think this would be suitable ?   Morris ATF

Edited May 20, 2025 by mk4savage

[sheffieldcortinacentre 726]

This stuff 204470149915 dexron 3 etc.

 

All the rwd fords Inc frogeye , C3,C4,4ald ,etc.

[mk4savage 62]

Thanks again Craig. 

 

One more question. If the current atf in the gearbox (comma brand) at the moment is a mineral based oil and I drain out as much as I can then re fill with dexron type fluid which I believe is a semi synthetic based oil would I end up with problems do you think ? 

 

I don't know if I'm reading too much into this but I want to make sure before I potentially mix incompatible oils. Cheers

[sheffieldcortinacentre 726]

That I don't know, but like you say get as much out as possible .

[mk4savage 62]

Ok Craig, thanks again. 

 

I did a bit of googling and some suggest it's ok to mix the two. 

 

One other interesting comment was you can use the mineral type oil for earlier boxes in the later red dipstick gearbox designed for dexron ATF but not the other way around. That's how I interpreted it anyway.