Slipping unless overdrive is off

This could be the overdrive band, but we need to find out a little more info as to when this slips.

Can you put it in manual 2 and leave the OD on and see if it slips.

If it still slips, then this could be the intermediate clutch or the overdrive. So that means we need to put it in drive with OD still on and see if when in 2nd gear at this RPM it slips. If it does in 2nd with OD on, then this is most likely the intermediate clutch that is slipping.

Also, we should check the fluid level and condition before we do anything just to be sure that is correct.

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

If you look at the attached info, the overdrive band is only applied in 2 manual and 4 overdrive.

So, we need to try and find out if the slipping only occurs in these gears to narrow down what this could be.

Let me know if you have questions on this. Thanks

Can you get a picture of the separator plate if you have not already put it back together? I think I know what you are talking about and that is most likely fine but seeing it will help.

Also, when you say the valves, are you talking about the valves in the valve body? If you have one that is sticking, then that is an issue. They should move pretty easily.

Can you remove the overdrive servo and see if you can get a look at the drum where the band rides? I bet it will look really shiny which means it is most likely slipping and not holding.

Got it. Yeah, that black plate needs to be replaced if it is that bad.

Sometimes the edges start to chip but if there is a crack in it then it needs to be replaced or you can have a fluid leak that will bleed off pressure. That black part is actually the separator plate gasket. There should be one on either side. See below for details.

If that valve is stuck then that could be the issue. That is the bypass valve and is used to control pressure and fluid flow. I am attaching info below on that.

Basically, there is either debris or build up on the valve or in the bore. So, take some Emory Cloth or steel wool and lightly sand it down so that the valve slides in and out smoothly.

The piece in your hand is the control valve plate that holds the valve in.

Let me know if you have questions with this.

Yes. The separator plate can be reused. Gaskets need to be replaced.

If the fluid was really dirty, then this is why they are saying you need to rebuild the unit. Any time you have slipping and dirty fluid that means it has been doing it for a while and it is safer to rebuild the whole unit while you are there.

You may get more life out of this unit but based on what I am seeing, you may need a rebuild but this may fix the issue in the short term. If I were doing it, I would rebuild it but that is because I have done a lot of these units and they are not too bad, but it is a lot of work.

If you take a look at the picture below. Number 1 is the solenoid screen

Number 2 is a converter drain back valve.

Number 3 I am not sure about. That looks like a cotter pin, but I am not sure where that goes.

Take a look at the attachments above of the exploded view of the valve body to show where they go.

Lastly for the plates, I don't remember having to replace them unless there is an issue.

Sorry for the delay. The spots are fine. That is pretty typical on those.

You can clean everything with parts cleaner spray. Just make sure you give everything time to evaporate.

Then soak any rubber seals in transmission fluid if you are replacing them. This just prevents any tearing when installing them into a bore. However, I am not sure you have any of these because you are just dropping the valve body.

I cannot think of any other parts that you will have to replace at this point, but we are going to have to test drive it once it is back together.

If the fluid was really dark and that much metal on the magnet then when you put new fluid in it, the clutches may not like it.

There is a myth that if you change old fluid that you are going to have a failure but that is based in some truth. Basically, what happens is when the clutches are damaged to the point that there is metal going through them then this grit actually helps apply the clutches, but it also damages them further. When you flush this out the now damaged clutches have nothing left to grab each other when they are applied and so it starts slipping.

Basically, I would just finish with what you are doing but prep the owner that we have to test drive it in order to make sure there are no other issues. However, you have no way of avoiding them. You can't do all this and not change the fluid or risk this from happening.

You have changed what you can from what you have removed.

The next step is, we need to remove the transmission. In order to change the band, we would need to disassemble the unit. Clearly that may be needed but if you are not wanting to do a full rebuild then I am not sure anything is possible.

Yes. Change the fluid. Even if you had the old fluid, I would still recommend changing the fluid.