Hey all, my 00 7700 4x4 has finally hit 199k miles this week and with that my 4r100 has decided down shifting should be a bit more interesting.

its never been perfect, we are talking about an old 4 speed but i liked how firm and consistently it always shifted, it reminded me of my rebuilt and upgraded c6 but even more "sure shifting".

Saturday i hit wot at 65mph where it usually downshifts to 2nd at about 4700 very quickly and the truck pulls hard to 4950 and shifts to third about 74 mph, this time it hit 5k, rev limited like 4 times then sorta eased about 50% in then slammed the last bit all at once.
(Normal)
4->2
2300->4700 (linearly but very firm)

(new and improved)
4->2
2300->rev limit for about 1.5 seconds-> some resistance->violent slam into 2nd at about 4800rpm

This also has come with a very awkward shift from park/neut-> with a real slow engagement to about 75% then the last 25% of 1st slamming in when i touch the throttle.

P/N-> 1st -> .75% -> light accel -> slam 100% into 1st

Upon normal accel it rows through the gears almost like normal, well within my tolerance and what this goofy a$$ computer has always done.

so, under light load with no powered down shifts needed, its normal, it also down shifts from O.D and manually into 2nd like normal.
N->
normal soft accel (normal)
normal soft decel (normal)
4th -> 3rd via O.D (normal)
3rd-> 2nd via column (normal)
2nd -> 1st (not possibly due to *****ty 10th gen shifter)

i should note, i have an sctx4 ive not done a custom tune with just just the built in adjustments to massage it into driving better via the following settings

1-2 shift pressure increased slightly
2-3 shift pressure increased slightly
3-4 shift pressure increased a lot (due to a 10°f heat rise with each extremely, stupidly, horrendously, slow factory O.D shift)
All shift points adjusted to shift to about 4900 +/- a bit so it never hits the decreased rev limit until now.
Rev limit 5000

I tow 4500lbs often and watch my trans temps carfully, its normally in the 170° F range and i ease off it it gets above that. On 2 occations it has hit 280° F. Once, i was intoxicated in a feild, second, i was towing 5k lbs up hill, and already 20 minutes late to a dead line I'd already pushed back. Both times i checked the fluids and no symptoms were observable.

I dont thing this trans is work completely out after 200k, it doesnt slip, shudder, skip, smell or look burned, so i think its the valve body.

As stated before i have had my c6 in my 78 rebuilt but but that was a 2 mechanic, 2000 dollar many, many month long ordeal so i dont want to do that anymore. I know i can install a valve body and stuff easily so i want to buy one, all the recommended parts/upgrades and do that as a first attempt.

This is where i would love to have some advice, honestly anything would help so thank you much!!

 

The first thing to do is to read the codes. I recommend Forscan, which can be downloaded free at wwwforscan.org. Their page shows how to select an OBDII adapter. I got mine from Amazon for about $30.

Once you have the codes we can diagnose the problem. Without the codes, start buying parts until you get lucky or run out of money.

 

I have an old laptop that should be functional and of course my samsung phone.
Im not great at computers but ill figure out what software to purchase when it comes in i guess. It should be here tomorrow thanks to the jungle site having one in stock.

thanks for that, i thought the O.D light would flash if it knew it had a problem.

 

Get Forscan for free at www.forscan.org. You don't need to purchase a license just to read codes.

 

===OBDII DTC P0122-P=== Code: P0122 - TP sensor circuit low input Status: - Pending - malfunction is expected to be confirmed Module: On Board Diagnostic II Diagnostic Trouble Code details TP sensor circuit low input This DTC may be caused by : Open Vref. Open Circuit Shorted TP sensor circuit low. Sensor Previously disconnected. Refer to the vehicle Workshop Manual for further system details Improper connection Low VREF TP sensor signal or VREF open circuit TP signal shorted to SIGRTN or ground TP sensor faulty or damaged Faulty or damaged PCM. Inspect connectors for signs of damage, water ingress, corrosion, etc. ===END OBDII=== ===OBDII DTC P0352-P=== Code: P0352 - Ignition Coil B primary circuit malfunction Status: - Pending - malfunction is expected to be confirmed Module: On Board Diagnostic II Diagnostic Trouble Code details Ignition Coil B primary circuit malfunction Note: This DTC could be the result of a calibration issue on certain 2000 MY applications. Reprogram PCM to the latest level. If concern still exits pursue ignition diagnostics. This DTC may be caused by : Open ignition coil primary circuit. Short to ground in ignition coil primary circuit. Suspect coil. Open ignition coil POWER circuit. Suspect PCM. ===END OBDII=== ===OBDII DTC P0443-C=== Code: P0443 - Purge valve circuit fault Status: - Confirmed - malfunction is confirmed Module: On Board Diagnostic II Diagnostic Trouble Code details Evaporative Emission Vapour Management Fault This DTC may be caused by : Open Circuit Short to Ground Short to VREF. ===END OBDII=== ===IC DTC B1202=== Code: B1202 - Fuel Sender Open Circuit Module: Instrument Cluster Diagnostic Trouble Code details Fuel Sender Open Circuit ===END IC=== ===IC DTC C1284=== Code: C1284 - Oil Pressure Switch Failure Note: This code may not be valid. Re-run the Self-Test with the vehicle running to verify the code. Module: Instrument Cluster Diagnostic Trouble Code details Oil Pressure Switch Failure Note: This code may not be valid. Re-run the Self-Test with the vehicle running to verify the code. ===END IC=== ===PCM DTC P0352=== Code: P0352 - Ignition Coil B primary circuit malfunction Module: Powertrain Control Module Diagnostic Trouble Code details Ignition Coil B primary circuit malfunction Note: This DTC could be the result of a calibration issue on certain 2000 MY applications. Reprogram PCM to the latest level. If concern still exits pursue ignition diagnostics. This DTC may be caused by : Open ignition coil primary circuit. Short to ground in ignition coil primary circuit. Suspect coil. Open ignition coil POWER circuit. Suspect PCM. ===END PCM=== ===PCM DTC P0122=== Code: P0122 - TP sensor circuit low input Module: Powertrain Control Module Diagnostic Trouble Code details TP sensor circuit low input This DTC may be caused by : Open Vref. Open Circuit Shorted TP sensor circuit low. Sensor Previously disconnected. Refer to the vehicle Workshop Manual for further system details Improper connection Low VREF TP sensor signal or VREF open circuit TP signal shorted to SIGRTN or ground TP sensor faulty or damaged Faulty or damaged PCM. Inspect connectors for signs of damage, water ingress, corrosion, etc. ===END PCM=== ===PCM DTC P0443=== Code: P0443 - Purge valve circuit fault Module: Powertrain Control Module Diagnostic Trouble Code details Evaporative Emission Vapour Management Fault This DTC may be caused by : Open Circuit Short to Ground Short to VREF. ===END PCM=== ===IABM DTC B1318=== Code: B1318 - The battery voltage level is too low. Module: Integrated Air Bag Module Diagnostic Trouble Code details Battery Voltage Too Low Battery Voltage Low This DTC may have been set as a result of a discharged vehicle battery or a poor supply connection to the heater unit. ===END IABM=== ===IABM DTC B1869=== Code: B1869 - Lamp Air Bag Warning Indicator circuit failure Module: Integrated Air Bag Module Diagnostic Trouble Code details Lamp Air Bag Warning Indicator circuit failure ===END IABM=== ===GEM DTC B1398=== Code: B1398 - Left Front Power Window Relay circuit failure Module: Generic Electronic Module Diagnostic Trouble Code details Left Front Power Window Relay circuit failure ===END GEM=== ===GEM DTC B1450=== Code: B1450 - Wiper select switch circuit failure Module: Generic Electronic Module Diagnostic Trouble Code details Wiper select switch circuit failure ===END GEM=== ===GEM DTC B1428=== Code: B1428 - Safety belt lamp circuit failure Module: Generic Electronic Module Diagnostic Trouble Code details Safety belt lamp circuit failure ===END GEM=== ===GEM DTC B1302=== Code: B1302 - Accessory delay relay circuit failure Module: Generic Electronic Module Diagnostic Trouble Code details Accessory delay relay circuit failure ===END GEM=== ===GEM DTC P1876=== Code: P1876 - Transfer Case 2-Wheel Drive Solenoid Circuit Open Or Short To Ground Module: Generic Electronic Module Diagnostic Trouble Code details Transfer Case 2-Wheel Drive Solenoid Circuit Open Or Short To Ground Follow the routines in the service manual to resolve the DTC listed. ===END GEM=== ===GEM DTC P0500=== Code: P0500 - VSS sensor circuit fault. Module: Generic Electronic Module Diagnostic Trouble Code details VSS sensor circuit fault. Open VSS circuit. Shorted VSS circuit. This DTC may be caused by : Suspect VSS. Worn or Damaged VSS drive gear on transmission output shaft. Suspect PCM. Faulty or damaged instrument cluster module. ===END GEM=== ===GEM DTC B1318=== Code: B1318 - The battery voltage level is too low. Module: Generic Electronic Module Diagnostic Trouble Code details Battery Voltage Too Low Battery Voltage Low This DTC may have been set as a result of a discharged vehicle battery or a poor supply connection to the heater unit. ===END GEM=== ===GEM DTC B1352=== Code: B1352 - Ignition key in circuit fault Module: Generic Electronic Module Diagnostic Trouble Code details Ignition key in circuit fault ===END GEM=== ===ABS DTC === Unable to read DTC Module: Antilock braking system ===END ABS===

 

Sorry for the horrible formatting, thats just how it comes out.

 

I'm sorry, I can't read that.

 

its judt random bs, after i cleared the old codes nothing but a evap code has shown up. I now have a guage on it and am uploading a video of it in operation.

 

Could be the valve body and also something finally wearing out inside the rest of the transmission, with one can go the other. Unfortunately, even with the best care, these are now 20+ year old trucks and seals just age out. My truck and its 4R70W only has 84k miles, I have had an original Greg Evans Factory Tech valve body in it for almost 20 years, but given its age there's always the expectation I might need to get it rebuilt sooner than later in the back of my mind.

 

this is a video of the problem,
if youll please take a few minutes to watch this and tell me what you think youll be saving me days/weeks of headache trying to diag and have this fixed myself.

if you have any questions, let me know

 

I didn't see anything unusual in the video. Did you?

 

Im ready to cut this old truck up if it will get it road worthy again, can i get a zf5 or 6 from the deisel to fit? Cant find anything really helpful. Thanks!

 

That is a RASH of codes
Recharge the battery
Clear codes and retest
Check all the grounds in the chassis, mainly those behind both kick panels
Codes like GEM module battery low are a sure giveaway for a there is a rash of codes to follow