4R70W Problems

[firehawk]

I finally have my bronco running and tried to drive it but I only have forward gear, no reverse. It is forward gear in reverse and in drive.

I assume it is a solenoid issue but would like some help with diagnosing it.

I already replaced a solenoid in it before I filled it up.

After I filled the trans up with fluid the motor does not rev like it did before I filled it. Any idea why?

 

[Viperwolf1]

Shift solenoid 1 needs to be on for reverse to work. That's a place to start looking. If you tell me the year I can tell you which pins to measure with an ohmmeter.

 

[jasonb]

Was the trans just rebuilt prior to you installing it in your Bronco? If so it could be a problem with the intermediate clutch. It is the last clutch to go in before the pump is bolted down. If the stack-up is not correct the pump will bottom out against the clutch holding it on at all times. This will give you forward movement in all gear shift ranges. Does it go forward in neutral also? If so, this is what I would suspect. The steel plates in the intermediate clutch are selective and the stack-up needs to be measured correctly to get the correct clearance in the intermediate clutch.

 

[Broncobowsher]

It sounds like you have a clutch pack applied (or stuck) when it shouldn't. My guess is a stuck valve in the valve body.

Engine won't rev in park, that also sounds like a stuck clutch.

Solenoids should matter. When I put the 4R70W in I forgot to plug the harness into the transmission. I had forward and reverse, just wouldn't leave 2nd gear going forward.

What is the history of this transmission?

 

[firehawk]

Shift solenoid 1 needs to be on for reverse to work. That's a place to start looking. If you tell me the year I can tell you which pins to measure with an ohmmeter.

It is a 99'

 

[firehawk]

Was the trans just rebuilt prior to you installing it in your Bronco? If so it could be a problem with the intermediate clutch. It is the last clutch to go in before the pump is bolted down. If the stack-up is not correct the pump will bottom out against the clutch holding it on at all times. This will give you forward movement in all gear shift ranges. Does it go forward in neutral also? If so, this is what I would suspect. The steel plates in the intermediate clutch are selective and the stack-up needs to be measured correctly to get the correct clearance in the intermediate clutch.

Not rebuilt, it is factory with about 130,000 miles on it. Yes I think it is in forward gear in neutral also.

 

[firehawk]

It sounds like you have a clutch pack applied (or stuck) when it shouldn't. My guess is a stuck valve in the valve body.

Engine won't rev in park, that also sounds like a stuck clutch.

Solenoids should matter. When I put the 4R70W in I forgot to plug the harness into the transmission. I had forward and reverse, just wouldn't leave 2nd gear going forward.

What is the history of this transmission?

Same as it was from the factory with 130,000 miles except I replaced the EPC solenoid already.

 

[Broncobowsher]

So the transmission wasn't tore down and the output shaft replaced. All you did was go into the valve body and replace the pressure regulator.
Did you remove the valve body to replace the pressure regulator?
I am still thinking that it is still just a stuck valve in the valve body at this point.

Getting a service manual out and checking pressures at all the pressure test ports could narrow it down. I would just pull the valve body, dismantle it, clean carefully, put together carefully and cleanly. Changing the EPC couold have dislodged a bit of grit or sliver of O-ring which is now creating the issue.

 

[firehawk]

So the transmission wasn't tore down and the output shaft replaced. All you did was go into the valve body and replace the pressure regulator.
Did you remove the valve body to replace the pressure regulator?
I am still thinking that it is still just a stuck valve in the valve body at this point.

Getting a service manual out and checking pressures at all the pressure test ports could narrow it down. I would just pull the valve body, dismantle it, clean carefully, put together carefully and cleanly. Changing the EPC couold have dislodged a bit of grit or sliver of O-ring which is now creating the issue.

I did not remove the valve body, just slipped the EPC solenoid in there. The trans was not tore down.

I would like to do more diagnostics before I drop the pan.

Where can I get the manual and a pressure gauge? How high does it need to read? Actually I have a rebuild manual, that should work.

 

[firehawk]

I tried unplugging the controller to see if it was activating a solenoid and started it up, still does not want to rev. Yesterday for some reason it did rev fine, but that did not last and it was only one time when I started it and could not replicate it.

 

[firehawk]

Google found me this but I don't think this is what the problem is unless this can happen while running the motor while the trans is not filled all the way, maybe only 3-4 qts.



I was told that the forward gear clutch set was fused together an that it is causing the trans to stay in first no matter what shift position it is in. Is this true??

 

[Broncobowsher]

Google found me this but I don't think this is what the problem is unless this can happen while running the motor while the trans is not filled all the way, maybe only 3-4 qts.



I was told that the forward gear clutch set was fused together an that it is causing the trans to stay in first no matter what shift position it is in. Is this true??

Look for the forward clutch pressure tap. Marked "FWD", third pressure tap back on the passenger side. It is standard pipe threads. Put a pressure gauge on there. A 0-300 PSI gauges will do. IF it has 0 PSI and wants to move, clutch is welded. If there is pressure there is an issue in the valve body.

The fact it wants to nuetral out when the fluid is low makes me feel the clutch isn't welded. Just low on fluid and couldn't build the pressure to apply the clutch. If it were welded it would want to drive even low on oil unless the convertor was so drained it couldn't provide any force. Only a few quarts low should have enough oil in the convertor for some driving force into the trans.

 

[Viperwolf1]

What gear does it go into in the different shift positions, commanded vs obtained? That should display on the controller. Also verify the MLPS is correctly adjusted.

Shift solenoid 1 and 2 should be 20-30 ohms. You can test them through the connector at the rear passenger side. Pins 4 and 7 for SS1, pins 4 and 8 for SS2.

 

[firehawk]

Look for the forward clutch pressure tap. Marked "FWD", third pressure tap back on the passenger side. It is standard pipe threads. Put a pressure gauge on there. A 0-300 PSI gauges will do. IF it has 0 PSI and wants to move, clutch is welded. If there is pressure there is an issue in the valve body.

The fact it wants to nuetral out when the fluid is low makes me feel the clutch isn't welded. Just low on fluid and couldn't build the pressure to apply the clutch. If it were welded it would want to drive even low on oil unless the convertor was so drained it couldn't provide any force. Only a few quarts low should have enough oil in the convertor for some driving force into the trans.

It never neutraled out.

 

[firehawk]

What gear does it go into in the different shift positions, commanded vs obtained? That should display on the controller. Also verify the MLPS is correctly adjusted.

Shift solenoid 1 and 2 should be 20-30 ohms. You can test them through the connector at the rear passenger side. Pins 4 and 7 for SS1, pins 4 and 8 for SS2.

I don't know that yet. I have just started to learn what the controller does so I will need to be coached step by step to give you that info. I will check the solenoids after dinner.

If you mean what gear does the controller show compared to the trans selector, it matches up from what I can tell.

 

[firehawk]

What gear does it go into in the different shift positions, commanded vs obtained? That should display on the controller. Also verify the MLPS is correctly adjusted.

Shift solenoid 1 and 2 should be 20-30 ohms. You can test them through the connector at the rear passenger side. Pins 4 and 7 for SS1, pins 4 and 8 for SS2.

Can I check the solenoids at the trans controller plug?

It looks like I don't have a number 7 wire going into the controller.

 

[Broncobowsher]

It never neutraled out.

But you said it did

After I filled the trans up with fluid the motor does not rev like it did before I filled it. Any idea why?

...Yesterday for some reason it did rev fine, but that did not last and it was only one time when I started it and could not replicate it.

If you unplugged the transmission (valve body) plug from the computer and you still get drive in nuetral, not willing to rev in park (loading up the convertor), and no reverse...
Quit chasing solenoids and wiring, it CANNOT be in there. You may have issues with wiring, but if you are having those problems with no power you have a (hydro)mechanical issue inside the transmission. Now way around that. With zero wires hooked up to the transmission you should still be able to drive it around, rev the engine in park or nuetral. It won't shift, stuck in 2nd with no engine braking.

Now to decide if it is a hydro problem or mechanical problem you need to check pressures. If there is pressure when there shouldn't be, you have a valve body issue sending fluid to the forward clutch at all times when it should turn the fluid on and off.

 

[firehawk]

But you said it did





If you unplugged the transmission (valve body) plug from the computer and you still get drive in nuetral, not willing to rev in park (loading up the convertor), and no reverse...
Quit chasing solenoids and wiring, it CANNOT be in there. You may have issues with wiring, but if you are having those problems with no power you have a (hydro)mechanical issue inside the transmission. Now way around that. With zero wires hooked up to the transmission you should still be able to drive it around, rev the engine in park or nuetral. It won't shift, stuck in 2nd with no engine braking.

Now to decide if it is a hydro problem or mechanical problem you need to check pressures. If there is pressure when there shouldn't be, you have a valve body issue sending fluid to the forward clutch at all times when it should turn the fluid on and off.

OK, so I need to get a trans pressure gauge, I will try to find one tomorrow.

Can I use a gauge that does not go to 300psi? Does it have to be a specific type of gauge?

 

[Broncobowsher]

Transmission pressures can go over 200 PSI. Lower rated gauges may not be happy if overpressurized. I just used some random gauge I had in the garage.

 

[firehawk]

Transmission pressures can go over 200 PSI. Lower rated gauges may not be happy if overpressurized. I just used some random gauge I had in the garage.

I got lucky and found one that goes up to 300psi in my garage, just need to mate it to the correct fittings to fit into the trans and I will test it tonight if I get it to work.