For those of you who regularly check out the 6.5 forum, you know about the diagnostic checklist.... well we've had a request to start one here. One can be constructed, but need a little bit of help in putting one together. This thread is for the construction/building of the list. I'm still learning about this, so I'm not an expert, but there are those one here. Together we can put together a list.

So, this thread is for the "beginnings" of building the list. Everyone can contribute questions etc, so that we can build one.

1. Fluid level okay while running, warm, level surface.
1a. Fluid color and smell
2. Speedometer reading correctly
3. Shifting normal/hard
4. Shifting into OD okay?
5. Any service engine light: yes/no
6. If SES light on, what codes do you have?
7. Model year:
8. Describe symptoms:
9. Does the engine come up to full temperature?
10. Any service work recently done that may contribute to your issues.
11. Does the TCC lock up (or how many "shifts" do you hear?)
12. Are you experiencing any kind of slipping?
13. What type of rear do you have? (Check RPO codes) 4.10/ 3.73/ 3.42 or 3.08
14. If you have an accurate tachometer, what is the RPM at 55 or 65?



What other ideas do you have?

does the TC lock up?
slipping?

11. What rear do you have? (3.42/3.73/4.10 etc) (Check RPO codes if needed)
12. If you have an accurate tachometer what is your engine RPM at 55 or 65 MPH (indicate)
13.

Great! This is going to bring DPlace to a new level!
Knkreb I hope Santa bring you a 6.5L/ 4L80E.

-Is the speedometer acting funny, not responding at low speed? This may be VSS sensor drop out. You can try swapping rear VSS with front one..

This is what I had on my Vehicle Speed Sensor (Vss) http://www.dieselplace.com/forum/showthread.php?t=160159.

The 4L80E is dependent on the Engine Control Module (ECM) for shifts. If confused the ECM puts it into “limp mode” giving 2nd gear only. The speed sensor can cause this type of confusion. This was good from FlashOffRoad “Output Speed Sensor and Various Other Sidetracks“.
(http://idiventure.com/flashoffroad/Maintenance/SpeedSensor/SpeedSensor.htm)ASA has this “Making Sense of Sensors” (http://www.asashop.org/autoinc/feb2004/mech.cfm) which gives detail on sensor drop out (under Variable Reluctance Sensor section).

2. Speedometer reading correctly
You already had it, sorry I missed it!

How about does ABS light come on?

Separate your troubleshooting first. Most people have a tendancy of imagining the worst. Even some techs fall into this catagory once in a while, trust me on this one. Follow some simple rules and you will save yourself time and money in the long run.

http://i120.photobucket.com/albums/o187/USMILRET/PreliminarycheckingTransmission.gif

Good stuff there guys... I'm just building a question/answer list to help elminate all the need for posting back and forth of "did you check this?" then finally pegging it on the 37th post of the thread. We could also build stuff for each individual "type" of problem. I'm a transmission dumby. I've only got a few ideas on a few things, but if we have common failures with things to check, we could build a FAQ section to help folk out with problems that do happen.

If you suspect that you have a sticky 1/2 solenoid, 2/3 solenoid, TCC solenoid or even PCS Force motor you can try these steps.

http://www.dieselplace.com/forum/attachment.php?attachmentid=51365&stc=1&d=1197172997

This is an opened case and it will help you out in understanding what you are doing with the previous picture.
The 1/2 shifting solenoid. The 2/3 Shifting solenoid and the Torque converter Clutch solenoid share the same pin E. The grounds are controlled at the computer when the computer wants to shift through "logic circuits".
Electricity Passes through the TCC solenoid and goes through the 1/2 solenoid and continues to the 2/3 solenoid. Like christmas tree lights, the only exceptions is that they are grounded in parallel. Wired hot in series but groundrd in parallel. No biggie. It just makes things simple, even for you when toy want to troubleshoot the shifting solenoids and the TCC solenoid.
Just remember Electronics can make it easy.
Also remember that 2nd gear uses no solenoid whatsoever, this is the reason why the transmission will default. When it defaults into 2nd it goes into maximum hydraulic pressure in 2nd gear. That is by virtue of force motor/PCS solenoid design that solenoid not receiving power is letting all of it go.

The best way to see inside a transmission is to use a "TECH 2" They will tell you things like how long it takes for the solenoids to shift, pressures to clutch components and what not but since most us cannot afford to dish out for one just get a pressure gauge and hook it up, make sure that the pressure line is long enough to reach into the cab from either through the floorboard or route it from under the vehicle and up through the window for observation.

Line Pressure Test should read:
Start the vehicle and check pressures in park, neutral and both drive ranges. Pressure should be a minimum of 35 psi at idle and increase to a maximum of 171 at greater throttle openings.
Shift the transmission into reverse:
At idle the pressure should read 67 psi and increase to a maximum of 324 psi as the throttle opening increases.
If pressures are low in all ranges the pump needs repair, worn gears blown out cross plug, cross leakage or worn bushing.
If pressures are too high then the fault may be with pressure control solenoid, reverse/boost or pressure regulator valves, bad TCM ground or solenoid connection.
While driving down the road you can really see how your transmission is shifting through the pressure. If you have a four wheel drive you can simply do the same thing while the transfer is in neutral and the vehicle is not moving. You are not hurting a thing.

So your Torque converter will not engage and give you that 4th gear huh? You suspect that the transmission is running too hot or you have a skewed transmission sensor. Go to radio shack and get two of those fine tipped multimeter leads that just fit over the pins L and M. Set the multimeter on the resistance scale and Place the transmission in drive with the transfer in neutral. make sure that the wheels are chocked. The transmission will heat up to around 140-150-160 range .
140 degrees will read anywhere between 580 and 750 OHMS
158 degrees will read anywhere between 419 and 525 OHMS
173 degrees will read anywhere between 293 and 371 OHMS

It would benefit you very highly if you get an infrared temp gun to measure the temp at either the oil pan or where the hot oil is going into the transmission oil cooler.
If the TFT sensor ohms reads otherwise then you might have a skewed sensor. The lower the resistance then the higher the voltage in the computer on that circuit.
Hot mode is when the computer will not let the transmission go into 4th gear. That's not the only reason why the computer will not let the tranny go into 4th gear, just one of them.

fyi data dump.
Here's a link to "700R4-Diagnosis-Fundamentals" (http://www.scribd.com/doc/487923/700R4-Diagnosis-Fundamentals) a 347 page pdf of web compiled trans stuff.

Wow guys... this looks great... we'll have to move a little bit of some of this stuff around for organizational purposes, but keep it coming! Thanks a lot!

i found this on the web. quite detailed info on transmissions. http://www.myrotarycar.com/portal/forum/uploads/RX8TX/Manuals/CD05-xx-03le/esicont/en/srvc/html/BHE050301026W04.html#wp1025486

This is in response to a member who wanted another picture of the transmission. As an update I will tell you that Pin E supplies voltage to the shifting solenoids but "Inside" the computer grounds each and every solenoid separately.
This includes the 1-2 shifting solenoid.
The 2-3 Shifting solenoid but 2nd gear uses no solenoids at all.
The TCC Solenoid. Remember that the 1-2 and 3-4 solenoid valves send pressure to the TCC solenoid valve. when both the 1-2 and 3-4 solenoids are actuated.
The PCS solenoid has its own characteristics entirely. It has a High and a low. C and D.
The line pressure works through amps delivered through the PCS solenoid. PWM, look it up through wikipedia, google. Easy to understand. It is a subject all unto itself and deserves understanding. Let them understand whom may.;)

Pin E from the connector feeds into the tops of these solenoids that you see in the posted image. they in turn go into the computer. The wires from that run horizontal from each of these solenoids that feed into the computer will be turned on and off by the computer as commanded by a separate switch.

When you want to uncover those mysteries as to why,why,why? If it is not a mechanical fault. If your fluid is full and not roasted like the coffee bean.
Remember that the sensors are 5 vdc
Tiss 5vdc.
Toss (if you have one) 5vdc.
VSS Variable Speed Sensor 5vdc
TFT (transmission fluid temperature sensor) 5vdc.
Transmission Range Pressure Switch, AKA Manifold Pressure Switch 5vdc.

Solenoids whether the shifting type or not are 12vdc
1-2 shifting solenoid. 2-3 shifting solenoid, TCC Solenoid and the PCS (Pressure Control Solenoid) AKA Force Motor.

This example should give you a good idea of what you might be experiencing with the transmission as you are driving. Should give you some insight as well.

Improved image for post #18. (Mods if you want or need to just replace the image from post # 19 and place it into #18.)

http://i120.photobucket.com/albums/o187/USMILRET/values.jpg

These are the resistance tables needed to check for shifting solenoids you have. The shift solenoid A is the 1-2 solenoid. Shift solenoid B is the 2-3 solenoid. Remember that the 1-2 and the 2-3 shifting solenoids must shift together to engage TCC. The Pressure Control Solenoid is referred here as the Force motor. The Transmission input speed sensor is (TISS) and for those of you who have the Transmission Output Speed Sensor (TOSS) the values are the same as (TISS).
Do not confuse (TOSS) with the (VSS) I do not have the values for the variable speed sensor.