TPS, Pot Mod, and overdrive issues

Update:

I bored out the TPS mounting holes and got it to low .60's at idle and 3.0-3.1v at WOT.

But even then OD doesn't work. All the other gears act normal, after being in 3rd in a few lockup occurs normally or I can engage it manually with the lockup switch. So lockup happens like normal. With the lockup switch off and in 3rd, if you de-illuminate the "OD off" button the converter will unlock like it normally would to shift into 4th, but it never shifts. Not if I lift, not if I hold up the brake pedal, not if I'm at 1/2, 3/4, or full thottle.

Next I found the brown wiring on the transmission plug. I did another drive and grounded it in various conditions [locked up, not locked, etc] No overdrive. So I guess that narrows it down to OD solenoid and faulty OD clutches.

Is there anything else I can check? Anyone have the part number for a OD solenoid? Looks like I'll be dropping the pan tomorrow and going to work on that...

Here's the most confusing thing to me: There were a few times the truck didn't go into lockup automatically. One of those times I had the TPS unplugged, lockup wouldn't work even with the switch. One time with the TPS plugged in I tried using my lockup switch and it didn't work. I shut the key off while coasting in neutral and turned it back on, suddenly lockup switch worked again. Does that have anything to do with a 'safe mode' or something like that? I've had the truck pop into 3rd in the past [very few times] and I had to go key off then key on and it would allow me to have OD again, but I think it was during a hard WOT run.

I'll be checking OD pressure in a few, gotta eat a late supper and head back out.

My bet is the solenoid then. But on a side note, i think the tps should put out 4.5-5v at wot.

I'm not sure about the issue with your lock up not working. if the connection gets grounded it should lock.

Sent from my DROID RAZR using Tapatalk 2

Just noticed something else, my radio channels are reset, as if I disconnected the batteries, but I have not. How the hell did that happen?

What I had from Peirs said 2.2-2..7v over the at idle reading.

I don't like where this is headed, sounds like some odd gremlins are screwing with me.

Anyone jumper the trans relay? I'm seeing that mentioned in 'limp mode' threads.

I hope it's just the solenoid at this point, I've got to pickup a car a few states away next week...

Bersaglieri said:

Just noticed something else, my radio channels are reset, as if I disconnected the batteries, but I have not. How the hell did that happen?

Click to expand...

now I'm too confused to even attempt to offer help, unless you pulled the fuse LOL

Sent from my DROID RAZR using Tapatalk 2

Yup I've got a Grade A cluster**** happening right infront of me.

Any idea what the OD psi should be and when should I test the pressure? My ATSG says OD should be 68-72psi minimum and 90-120psi max, but doesn't say to test it at rest or ??

Bersaglieri said:

Yup I've got a Grade A cluster**** happening right infront of me.

Any idea what the OD psi should be and when should I test the pressure? My ATSG says OD should be 68-72psi minimum and 90-120psi max, but doesn't say to test it at rest or ??

Click to expand...

I have no idea on that

Sent from my DROID RAZR using Tapatalk 2

Found this:

"Move 300 psi Gauge to overdrive clutch pressure test port.
Increase vehicle speed gradually until 3-4 shift occurs and note gauge pressure.
Pressure should be 469-496 kPa (68-72 psi) with closed throttle and increase to 620-827 kPa (90-120 psi) at 1/2 to 3/4 throttle. Note that pressure can increase to around 896 kPa (130 psi) at full throttle. "

Sounds like it needs to grab 4th to check pressures. Although I did read that it should be getting 5-15psi fill pressure even if it's not engaged. I'll probably put the gauge on there regardless and see what happens.

I'm going to see if I can find a solenoid test procedure as well.

The fuse is for the trans relay, the lockup, OD, and variable force solenoids share the same 12v power supply from said relay. You were experiencing a safe mode before, and yes a jumper will solve being locked out of OD.

Lockup/OD solenoids come as an assembly P/N 12420B will come with the solenoids and a new internal harness. The pressure check is to see if it's A) maintaining the 5-15psi prefill pressure and B) if there is a small pressure spike that doesn't reach the 60psi minimum when OD is supposed to apply. If it maintains 5-15psi with no spike at OD command, it's the solenoid. Blown seals can still sometimes hold the 5-15psi, but can even drop pressure when the shift is commanded, though they normally get a little spike first.

It still sounds like a possibility of two common problems to me, OD solenoid, or blown OD seals caused burnt clutches.

EDIT: Ohm out the solenoids through the harness, the ATSG should have the resistance listed, then also crawl under your truck and have someone cycle your manual OD switch with the key on and listen for the solenoid to click.

Wow, thanks Stan, that's all great info.

So should I just jumper that replay to prevent limp mode altogether?

I'll get the gauge on there after lunch and report back, I'm going to the oreily's distribution warehouse an hour away to get the solenoid since no one can get it here today, not even Mopar.

I don't have Ohm anything in that ATSG. It's detailed in some aspects but seems to be lacking in electronics. Could you give me a crash course? I'll try the audible solenoid check as well.

Thanks guys.

Just ran out and grounded the solenoid for an audible test, I can hear a faint clicking... should I skip the solenoid purchase and just plan on pulling the whole trans or OD section out?

I would do a pressure check to verify that the ball inside the solenoid is sealing up, I've had them pass ohm and "click" test and still not apply the gear. Always better to be safe then sorry, it's a one hour job to change those solenoids VS a half a day to get the OD off rebuilt and back on.

Basically just the port pressure check to see what it's doing? I didn't get to it yesterday, the weather screwed things up for me.

Yes, it's just to verify that there is a small spike in pressure to completely rule out the solenoids. If you don't mind me asking, what was ORielly's gonna charge you for the solenoids and was it just the pair or did it come with the harness too?

$118-125 + tax for both solenoids and the harness.

So I finally got around to checking the pressure today. Now I'm not claiming my gauge is perfect, but it's the only one I've got.

Driving normal in 1st, 2nd, 3rd I see nothing for fill pressure. The gauge doesn't move. [ATSG claims 0-5psi fill pressure] If I command 4th either with the ground or OD button the pressure jumps to 32-45psi and holds there. I tried it at various RPM's and they all seemed to fall somewhere in that range. Now it spiked to a few different pressures, but held wherever it spiked to, no drop.

Now here is where I think my gauge has issues. Sometimes I went back to 3rd the gauge read 15psi, which I thought might have been the fill pressure, but if I tapped the gauge it dropped to zero again. Just sticks a little I think, I tapped it while 4th was commanded and it didn't move.

I'm waiting to hear back from the guy who built the transmission, I don't blame him at all, but I am enlisting his help on diagnosis. He wanted me to check the pressures and possibly check the pan for random clues.

So seems like the solenoid works, but there is still the chance of a lower valve body issue right? Should I consider sending it back to Garmon to go through if I'm going to take the OD off anyways? I've been meaning to do it anyways to get 2nd gear lockup put activated. I'll probably call Jeff in the morning just to pick his brain. However I'd have no problem taking it apart myself, I've done valvebody builds plenty of times before.



Here is what ATSG says about Overdrive clutch failure:

When the overdrive clutch fails it will either slip shifting into fourth gear or it will not go into fourth gear at all. If there is not shift to fourth gear you can verify if the transmission has attempted the shift to fourth by doing the following check. Drive the vehicle under the conditions that should allow the transmission to be in fourth. While driving take your foot off the gas. If the vehicle has no engine braking and coats freely, the overdrive clutch has failed.

Here is what ATSG says about Overdrive solenoid failure:

If the solenoid fails so it stays open the transmission will never upshift into 4th gear. If it fails closed, the transmission will upshift from 2nd directly into 4th. Check for fault code.

Here is what ATSG says about Overdrive piston and lip seal failure:

If the piston or lip seal failed, causing hydraulic pressure loss, it could cause the direct and overdrive clutches to fail. The first place it would show up would be during the shift into 4th gear. Third gear would appear to be operating properly because the of the overrunning clutch.

Did you try the coast test? Totally forgot about that one... 45psi should have been enough to release the OD direct anyway. It sounds burnt with a bad outer seal to me though.

Also, if you can mix JB weld and use a razor to cut it flush with the top of a passage you can do the 2nd gear lockup mod yourself :Cheer:

Alright, I have a screwy update.

I put off fixing the trans until I had a few projects done around the house. A few months turned into 6 and today I was getting the remaining lumber for building. I planned on pulling the transmission at weeks end. I tried engaging OD a few times during the 6 months, same problem, it demands OD, gets 30-40psi, and doesn't do anything else.

UNTIL TODAY...

Towing my gooseneck while getting onto the highway I hit the OD button out of habit, "stupid" I thought, "that crap is broke" WRONG!, before I can turn it off the truck grabs OD and the RPM's drop. My face must have been priceless. I look at the gauge still on the OD port; 135ish psi of pressure. I had a sh!t eating grin the entire way home.


Now, I worked outside in the 105 degree weather the rest of the day, so my mind isn't processing why OD came back. Anyone got some ideas? The clutches must be fine cause I ran 85mph down the highway trying to get OD to fail again, but it didn't.


.

I love it when they fix themselves lol. Mine goes in and out of lock up when it's really cold or if its raining out. Even with my lock up switch on. Yanking the Trans soon anyhow to install my billet input and billet Tc.

I can't replicate the experiment... OD gone again. Tomorrow I'm throwing on the trailer to see what happens. I'm baffled.