4R70w No 4th and no engine braking in remaining gears

[FIXR7]

Hi All,

My 4R has lost OD or slips so badly it feels like it's not in OD. It's shifted by a Baumann Optishift and it is indicating it has shifted there. the remaining gears shift fine but there is no engine braking in those gears.
I pulled the pan and it's all very clean. Pulled the VB and checked the 3-4 cover for the dreaded broken snap ring but nope, all good. On advice of the trans builder I replaced the shift solenoid, put back together and no difference. Does this mean I have a broken OD band? Or something worse? Trans is only two/three years old so I'm thinking they did something wrong when building it. If I think about it I believe the loss of engine braking occured before the OD fail.

Cheers.

 

[JK080]

When the 4R70W shifts from 3rd to 4th the 3-4 shift valve moves and shuts oil off to the forward clutch and applies the OD band. If the band is broken it should feel like it went into neutral on the 3-4 shift, if it just feels like it is just not shifting into 4th then the 3-4 shift valve didn't move.

You said you checked for the OD servo for a broken snap ring, but sometimes the small e clip will break and a small piece will fall down into the valve body and block the valve.

So maybe take another look at the valve body, as in take the plate off and check the valves.

 

[FIXR7]

Thanks James,

I've pulled the trans out now so I'll investigate that part first.
Any theories on the cause of no engine braking in 1,2,3?

Cheers,
Pete.

 

[FIXR7]

Btw is it normal for the trans harness connector to be full of oil?

 

[FIXR7]

Sorry, Also which shift solenoids are operated for 4th?

 

[JK080]

Btw is it normal for the trans harness connector to be full of oil?

No it can cause connection issues.

Sorry, Also which shift solenoids are operated for 4th?

Both shift solenoids on is 4th gear.

 

[FIXR7]

No it can cause connection issues.



Both shift solenoids on is 4th gear.

Thanks James. is there a seal missing or broken if that's the case?

 

[JK080]

The case connector itself has to be replaced to stop the leak into the plug

 

[FIXR7]

Ahh ****e! Not like to be any of those around here

 

[JK080]

Not sure what year model you are working on but if the internal wire harness has wires instead of the later version with a molded strip, you may be able to clean and epoxy the back of the connector to help with the leak. If you have the later version then you have to replace the connector.

I would be surprised if the oil in the connector is the problem that you are experiencing, if it neutrals out on the 3-4 shift its a problem with the band, if just no 3-4 shift then the problem is most likely in the valve body.,

 

[FIXR7]

Not sure what year model you are working on but if the internal wire harness has wires instead of the later version with a molded strip, you may be able to clean and epoxy the back of the connector to help with the leak. If you have the later version then you have to replace the connector.

I would be surprised if the oil in the connector is the problem that you are experiencing, if it neutrals out on the 3-4 shift its a problem with the band, if just no 3-4 shift then the problem is most likely in the valve body.,

Yes I think there would be problems with other gears shifting and most likely intermittant problems. It's a '98-up type with the molded harness. It's built by Hughes Performance. I've taken it to a trans shop now. we'll see what they find.Thanks again James.

 

[FIXR7]

Btw James, I noticed a faint whistling sound coming from the trans when I shift into park. Sort of starts off high then drops down in pitch.

 

[FIXR7]

Ok pull down has so far revealed a broken OD band. What causes this?

 

[JK080]

Ok pull down has so far revealed a broken OD band. What causes this?

They just do that sometimes... broken bands plaque a few other transmissions as well, most of them are Fords.

As for the whine noise going into park, it could be a few things. Check the thrust bearings in the transmission real close and it could even be the converter itself.

 

[FIXR7]

Thanks James, Can you get stronger ones from anywhere? Obviously its the metal part that broke.

 

[FIXR7]

Ok the trans shop put a factory band in it and some new frictions. But I've since discovered that they didn't open the valve body. So now it still doesn't engine braking but only in 1st and 2nd. Is that a stuck valve or sommet in the VB?

 

[FIXR7]

Hi James.
I want to buy a reman VB from Sonnax but they want to know what year VB I have. Hughes are so hopeless they're asking me which one I have in a trans they built!?
So it's supposedly a '98-00 type trans.
Can I use either a '98-00 VB or '01-'04 VB? Hughes can't even tell me that!? I don't want to pull it out to find out which one I have unless I have parts to fix it. Obviously I don't want do the job twice.

Regards,
Pete.

 

[JK080]

The valve bodies are different. you need to stick with the correct one for the year model you are working on.

 

[FIXR7]

Thanks James

 

[FIXR7]

G'day Folks,

Yes, I still have this problem. ie; No engine braking in 1 or 2. Everything else works fine and have just put up with it till now. Obviously no engine braking is not much fun when bush bashing on steep hills!
SO anyway I've pulled the VB but not disassembled it yet. It is in indeed '98-'00 spec.