Transmission Help

[Skye]

Hello everyone,

It took all summer (mainly waiting on parts as we discovered we kept needing more) but my boyfriend and I finally got my transmission rebuilt. We followed the rebuild book to a T.

Little bit of back story: in June we noticed I was having issues with 2nd gear so we decided to do the 2nd band adjustment. We did the adjustments and went to take Pig (that's my trucks name) for a test drive. We needed grease so we decided to take her up the road to the parts store. Got to the parts store and she wouldn't shift into park and 2nd gear was still slipping. Thus, prompting the removal and rebuild of my 48RE.
Bought a rebuild kit and realized that it didn't come with everything so we started ordering the parts we needed. We upgraded and put some billet parts in the valve body, but during the rebuild we noticed that the transmission was built for gas, not diesel.
Fast forward to today:
We finished buttoning her up, plugged everything back in, refilled the coolant, transmission, oil and started her up. Took her for a test drive and there is a indescribable sound coming from underneath. She also seems to be starting in 3rd and not shifting. And she has almost no power. Was pedal half to the floor to get into my not very inclined driveway. Attempted to manually shift and it does nothing. Came home, plugged in the code reader and got codes: P1749, P0973, P2769 & P0868.
I've looked all 4 up online and the most common denominator is bad PCM/ECM.

There is still a tuner under the hood but it was disconnected when I bought it. Attempted to hook it up but no dice. Seems to be dead.
2005 5.9L 4-Wheel Drive 136K miles
Airaid cold air intake
Billet servos
New Governor pressure sensor
New radiator
New power steering pump
Upgraded 2nd gear band

Also, I've checked the fuses and relay's and they aren't blown and are getting power.

 

[Timd32]

I wonder if your manual valve is not correctly.




Noise wise maybe your Torque Converter is not on all the way?

There is a measurement for that when it's in all the way on the Trans. Besides they are heavy as all heck.

48RE is still a very old school Trans so pressure controlled 1,2,3.

But only a few things cause 3rd gear starts, one being the internal temp sensor, there are 2 kinds of those. Did you swap all the internal and harness? Check your old vs new for ohms and make sure you put the right one back in.

Maybe getting that noise sorted, manual control, maybe check your pressures and don't drive it till you know you have it sorted does not take long to cause some damage.

 

[Ozymandias]

I was just looking up all the codes you get and together with the slipping - you have a hardware problem, not the ECM.

Did you monitor the line pressure while doing the test ride? That would be the first and most important information in the troubleshooting tree.

And most basic, how did you measure fluid level? Running low on ATF gives all kinds of bad trouble, including bad sounds. And I know how difficult it is to measure a 48RE correct. It takes forever to get a decent reading in the dipstick.

 

[Skye]

Seeing as how this is my first transmission rebuild, I did not know about monitoring pressure in the lines. However, here is how I refilled the transmission:
Before I started the truck, I pumped ATF until the dipstick read full. Then I started the truck, and put some more ATF into it. Then I shifted it into neutral, drive and reverse a few times before I let her run for a few minutes before checking the levels and adding some more in. After the first test drive, I checked the levels again.
Went through and checked all my bolts today, and my exhaust was rattling against the frame, so the noise is gone.
Cleared the codes yesterday and they haven't come back. However, the truck still seems to be stuck in one gear.

I was just looking up all the codes you get and together with the slipping - you have a hardware problem, not the ECM.

Did you monitor the line pressure while doing the test ride? That would be the first and most important information in the troubleshooting tree.

And most basic, how did you measure fluid level? Running low on ATF gives all kinds of bad trouble, including bad sounds. And I know how difficult it is to measure a 48RE correct. It takes forever to get a decent reading in the dipstick.

 

[Skye]

I should have stated, this is an automatic transmission.

I wonder if your manual valve is not correctly.




Noise wise maybe your Torque Converter is not on all the way?

There is a measurement for that when it's in all the way on the Trans. Besides they are heavy as all heck.

48RE is still a very old school Trans so pressure controlled 1,2,3.

But only a few things cause 3rd gear starts, one being the internal temp sensor, there are 2 kinds of those. Did you swap all the internal and harness? Check your old vs new for ohms and make sure you put the right one back in.

Maybe getting that noise sorted, manual control, maybe check your pressures and don't drive it till you know you have it sorted does not take long to cause some damage.

 

[Timd32]

Manual valve is for the Automatic Trans, it's what selects the gear.

You should have manual control of forward gears. Which is why I posted that video of the rooster comb deal.

If you have manual control, say Manual 1st, but still 3rd gear starts...

Double check your Transmission Control Relay, (TCR), it in the Intergrated Power Module (IPM).

You should have battery voltage from Fuse 5 (40A) to pin 30 at all times. Then with the relay back in when you have the Key ON Engine Off power out down to the Trans from Relay Terminal 87 the Yellow with Orange stripe wire, goes to Pin 1 of the Trans.

I thought that when you had no power to the 8 pin plug you got full line pressure, but really don't remember. Without a gauge not super important but you can check the pin voltages.

I feel manual 1st should not be impacted by the electronics except you won't have control of the governor pressure. So you should not really operate the Trans like that for long periods of times.

Usually there are spare relays to swap I'm. They are all the same usually.

Also I found a Learn function that is listed in the manual. That is attached.

But I think it's a simpler issue here, since you don't have basic gears, like Man 1st.

 

[Ozymandias]

Buy a twenty Dollar transmission oil pressure gauge - and make sure that it has at least an 8' hose on it. 6' works with a passenger reading the gauge outside, 4' doesn't work at all. Thread is 1/8NPT female - the standard that all these gauges come with, no need for an adapter on our trannys.

You get it on Amazon.

Without knowing what's going on pressure wise we can't help really.
Pressure is THE most important thing in an automatic transmission.

Level is checked in Neutral with the engine running, that's correct.