Self - rebuilt 700R-4 Elite Pro-Built Automatics Dana kit.

No OD, or is it in OD and not locking up?

New shift cable. Can feel the shifter move through all positions. Smoothly in and out of reverse.

Adjusted the TV cable, 1-2-3 shifts are smooth at good RPMs

In OD street driving normal accel and decel I feel it shift smoothly well 1-2-3 and 3-2-1. But no OD.

In OD hard accel it shifts firmly 1-2-3 but no OD up to 100mph. On lifting pedal and trying to cruise at 90, 80, 70 it does not go into OD.

In OD at 45 mph if I pull the shifter down to 3 nothing but into 2 it downshifts manually. Also to 1 it downshifts manually when I do it around 25mph.

In OD cruise at 65 mph then hard accel it feels like it shifts down into 3rd. RPM's go up and it feels like a downshift. However on pedal lift it does not upshift, RPM stays high. I cannot coax it to OD with a steady pedal.

When in 3rd and I give some pedal a few hundred RPM more it feels like it's slipping, the trans absorbs the RPM without accelerating. Like lockup is not on.

I shorted A and F pins and I’ve got lockup in 2 and 3.

I understand OD is 100% internal pressure controlled. I do not have a gauge (yet) and do not know pressures at this time. Should that be my next step?

Thx for comments.

 

If the ATF Level is down a bit, the THM700-R4 often will not Up-Shift to 4th-Gear.

Going into 4th-Gear requires most of all the ATF Capacity be used to apply the Forward Clutch, 3-4 Clutch, Intermediate Servo Piston Area, and the Overdrive Servo Piston Area.

The Oil Pan is somewhat shallow, and the Transmission needs every bit of FULL Fluid.
Try Over-Filling another Half-Quart to One-Quart to see if 4th-Gear will shift.

Otherwise taking Line-Pressure Readings is always helpful information to have.

Also if your Case has 3 more Case-Plugs installed on the side that the Servo Assembly is located...
Then you have a Overdrive Servo Fluid Pressure Port that you can take an additional Measurement from!

 

Will try filling more thanks. I've got a cooler in front of the rad so that surely takes some. Will report back.

 

I had similar issue once. Discovered there is a small drain port that accidentally got covered with the thin layer of RTV I put on the pan gasket. If that port is blocked it will not shift to OD. My fix was remove the pan and reapply RTV more carefully so the hole drained freely.

 

Did you install the servo assembly as one, including the cover. Or did you install the cover with the assembly in place (case)? If the latter, then you might have damaged the seal on the OD piston.

 

In my efforts to stop leaks I went from trans specific RTV to a Farpak gasket. I found the fluid softened the RTV so much that I could scrape it off the trans and pan with my fingernail.

However I am open to having left a bit of RTV in there which I will check for as a last resort. I probably would drop the valve body and give it a thorough cleaning if it gets to that point.

 

Can't remember, but something else to check thanks.

I read on transmissioncenter.net about how no OD could be debris, a bubble, or a stuck valve. Recommended lifting the tires and spinning it up to 100 and popping the throttle to see if it would go into OD.

 

Wow a month later, had some time to try

1. Add more fluid - Reading is way above full now, but still no OD.

2. Bring it up to 100mph with tires lifted, pop the throttle to clear bubbles or debris. Did not give me OD.

3. Vortec, I only have the driver side port for pressures. I have attached the pressures I took this afternoon. Please take a look.

Next I will pull the servo assemble and inspect. After that I will drop the valve body and look for debris.




Thanks for comments.



Tim

 

Curious how you made out? Did you get OD yet?

 

I discovered I left out the washer as shown on the sonnax website for the 4th gear Super Hold Dual Servo kit # 77767K. So I believe there was too much space in that assembly. I also believe this spacing is controlled by the 2nd gear Super Hold Servo kit #77911-03K which involves grinding the apply pin down to achieve the proper servo travel which must be within a certain range.

After getting and installing the washer (who knows where the original went) and doing my best to measure piston travel under the car I believe I am within travel spec now.

To get the trans low enough to do all this I removed the aftermarket torque arm at the diff and could not get it to slide back on easily, so I need to loosen it at the front to get it back on. Then for a test drive to see if 4th is there.

Hopefully in the next week or two, time keeps slipping away....

 

Let us know.

There is a big list of reason why a no 4th-Gear or Intermittent 4th-Gear Situation could occur.
The list changes some when the Transmission is done DIY.

 

I have seen this a few times with the Sonnax 4th apply servo setup, and get calls on this even though it is in the instructions.
At least it should be solved

 

FINALLY!

Yes the missing washer was preventing the shift to OD. This wraps up a year-long rebuild (time was my limiting factor). Not remembering where I left off, not being crystal clear on some assemblies, spilling trans fluid on Dana's instructions, all part of the fun!

Big thanks to Dana for his elite kit and his support as well as contributions here esp Vorteciroc.

Now back to stepping up the boost!

Cheers, Tim