Gearbox service

[Kev0607]

Hi,

I'm planning on doing a drain & fill of the transmission's on my car (S80) & my Dad's V70 (both P3 shape). Both cars require JWS3309 fluid, which I'm aware of.

Would you recommend doing a drain, filling it back up & driving for say 1,000 miles or so before repeating the process. Or, would you just advise draining & filling all on the same day until the fluid becomes its original colour?

I understand that you can only get around 3L out of the transmission at a time via the sump, due to fluid being trapped within the internals.

I'm going to get one of the 20L drums on Ebay made my Mannol, as that'll do both vehicles.

[Bashy]

Thats what they say, i think it may be 500 but i cant see 1000 hurting any

[Tannaton]

500 miles will give you a full mix. 15 miles will give you a 99.99% mix.... it’s more important to cycle through all the gears a good few times than sit on the motorway for a while.

[XC90Mk1]

Originally Posted by Kev0607

Hi,

I'm planning on doing a drain & fill of the transmission's on my car (S80) & my Dad's V70 (both P3 shape). Both cars require JWS3309 fluid, which I'm aware of.

Would you recommend doing a drain, filling it back up & driving for say 1,000 miles or so before repeating the process. Or, would you just advise draining & filling all on the same day until the fluid becomes its original colour?

I understand that you can only get around 3L out of the transmission at a time via the sump, due to fluid being trapped within the internals.

I'm going to get one of the 20L drums on Ebay made my Mannol, as that'll do both vehicles.

When you drain, circulate for 2 mins then do again it does not mix the fluids. I have experimented with it.

Drain, then drive 200 miles and redo.

[john493]

On the TF80 transmission, worthwhile to also check you have the latest software installed.

[Tannaton]

Originally Posted by Tannaton

500 miles will give you a full mix. 15 miles will give you a 99.99% mix.... it’s more important to cycle through all the gears a good few times than sit on the motorway for a while.

I'd just like to clarify what I meant - it's more important to cycle through the all the gears several times whilst on a good drive, not sat parked on the drive...

[Kev0607]

Originally Posted by XC90Mk1

When you drain, circulate for 2 mins then do again it does not mix the fluids. I have experimented with it.

Drain, then drive 200 miles and redo.

I thought the same.

Lets say the existing fluid in the transmission was very dirty. How many times would you need to repeat the process to get the fluid clean would you say?

This would be based on doing drain & fills over a period of time with 200-500 miles in between each fluid change.

Also, would it be okay to reuse the rubber washers/o-rings that go on the transmission drain plug whilst doing these drain & fills, but replacing them with new ones on the final drain & fill when the fluid is clean? Otherwise, it means replacing the o-rings every single drain & fill... seems a bit of a waste of o-rings when only doing 200 miles or so in between changes.

[Bonefishblues]

Didn't the/an E European guy publish a video plus bottles which of the 5 (IIRC) changes he did, showing the change in colour. It's out there somewhere

ETA
Yep, he did, and it is

https://youtu.be/EAb9p8Wph-M

[XC90Mk1]

Originally Posted by Kev0607

I thought the same.

Lets say the existing fluid in the transmission was very dirty. How many times would you need to repeat the process to get the fluid clean would you say?

This would be based on doing drain & fills over a period of time with 200-500 miles in between each fluid change.

Also, would it be okay to reuse the rubber washers/o-rings that go on the transmission drain plug whilst doing these drain & fills, but replacing them with new ones on the final drain & fill when the fluid is clean? Otherwise, it means replacing the o-rings every single drain & fill... seems a bit of a waste of o-rings when only doing 200 miles or so in between changes.

I actually did it. I put 2.7l of fresh fluid in, circulated through park, R, N and D a couple of times and dumped. Put came quite nice red fluid. Job done hey! Then I went for a 100m drive and it was filthy again.

The fluid will not circulate the box you do need to drive a decent distance.

[Kev0607]

Originally Posted by Bonefishblues

Didn't the/an E European guy publish a video plus bottles which of the 5 (IIRC) changes he did, showing the change in colour. It's out there somewhere

ETA
Yep, he did, and it is

https://youtu.be/EAb9p8Wph-M

I've watched that video before. It seems though that he's pouring litres upon litres of fluid into the transmission, cycling through the gears for a short while & then draining the fluid again... this doesn't allow the fluid to mix properly.

I'm not critizing the video, as its very clear & well put together. I suppose I'm offering my opinion, or it may be considered constructive criticism.

The chap in the video isn't bringing the car for a long drive in between the drain & fills. Even if he didn't go for a long drive on the day he drained the fluid for the first time, he could have done a few hundred miles over a period of time before draining it again & then repeated the process with a few hundred miles in between each drain/fill until the fluid was clean.

Pouring fluid into the transmission, cycling through the gears whilst the car is still on axle stands & draining it after a few minutes seems pointless to me.