4R70W Problems

[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.

Do I check it in park or in gear?

 

[firehawk]

90 psi in park and in gear.

What did you mean by neutralling out? Free rev while in gear? Never did that.

I meant it would rev normal while in park until I filled the trans and then it became sluggish and wouldn't rev past about 3000.

 

[G's Baja Bronco]

I had a similar issue on my AOD, it would OT rev past 3k on park and is would rotate forward on reverse, neutral and od, d and L. It turned out it had a burned up direct clutch pack, it basically welded together the drum, frictions and steels. good luck, I will keep an eye at this thread.

 

[Broncobowsher]

90 psi in park and in gear.

What did you mean by neutralling out? Free rev while in gear? Never did that.

I meant it would rev normal while in park until I filled the trans and then it became sluggish and wouldn't rev past about 3000.

90PSI in park is a problem. It is in gear when in park.

Rev normal in park when low on fluid is exactly what I would expect. You didn't have enough fluid to build hydraulic pressure to engage the clutch. So it reved like it was in nuetral. Add fluid, clutch applies, it is now always in gear (so long as the engine is running and putting pressure into the forward clutch).

I would definatly clean up the valve body at this point.

 

[firehawk]

90PSI in park is a problem. It is in gear when in park.

Rev normal in park when low on fluid is exactly what I would expect. You didn't have enough fluid to build hydraulic pressure to engage the clutch. So it reved like it was in nuetral. Add fluid, clutch applies, it is now always in gear (so long as the engine is running and putting pressure into the forward clutch).

I would definatly clean up the valve body at this point.

I will drop the pan this weekend unless I can get to it sooner.

Anything in particular I should or should not do to the valve body?

Take it out and spray it down with carb cleaner?

 

[Bronchole]

Shouldn't he replace the gasket for the valve body when he re-assembles it? If so it would likely be nice for him to know so he can get it in advance.

 

[Broncobowsher]

Shouldn't he replace the gasket for the valve body when he re-assembles it? If so it would likely be nice for him to know so he can get it in advance.

Good point. I had a stack left from when I put the shift kit in. Good thing is the factory pan gasket is reusable and is a good one as well.

 

[firehawk]

Found the problem, my fault.

When I put the new solenoid in I did not pay attention to the shift linkage in the trans, it need to mesh with the plunger in the valve body to move when the shifter moves, mine was not engaged with that plunger so it was wherever it was but not where it needed to be.

I am sure it took some life out of the clutches but I drove it today for the first time since last year which is about 2 months behind schedule but the trans felt great, holy barkin the tires in second

Now I have to work on the bauman shift points for the trans and the 205 transfer case seem like it wont go into 4 hi, seems like the 205 shifter and shift rails are hitting the trans adapter. Anyone have this issue?

 

[firehawk]

I forgot to take pics of the crossmember I built (I will get some when I pull it back out to repaint it and the brackets) but it work with the stock brackets that mount to the frame. I think it will be a good design to make and sell for the 4R70W and NP205 swap. I used 1/8" plate to make the initial design and then doubled it up and chamfered the edges and welded all along the perimeter and drilled holes to plug weld them together also. I am using the stock rubber trans mount from the Mountaineer.

I used a poly mount for the transfer case though, will this cause a problem? If so I will swap out the motor mounts with the extreme poly ones but will probably make them and a poly trans mount also.

Still need to put 5.13 gears and lockers in when I get the time.

 

[Rox Crusher]

Did you put a drain plug in the pan while you had it off ?

 

[firehawk]

Did you put a drain plug in the pan while you had it off ?

I put one in it before I put the trans in and I am glad I did but I think I am going to change the location when I have the pan off next time.