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What did you do with your GMT400 today...or yesterday....

FSO doesn’t add up to me because that solenoid is either on or off.

Plugging intermittent return line is a possibility- but doesn’t feel right with your description.
I just ran out there to look at it. it's still connected but my rigging is a wire ran through the hole in the spade and folded over then a normal male spade crimped on to that wire connecting to the female spade in the harness. not great but it's what I had done when I first got the truck running when I bought it. then neglected to go back and fix it right!! oopsies!
 
Nothing more permanent than a quick fix to get home! 😂
If you did get water in the fuel- the factory filter is maxed by time it turns on the light. Filter change now.
This is the part where I promote FASS water separator filter. I like the fass LP with filters because it’s designed to work together and does it well. But if that isn’t an option, consider getting just the filter & a stand alone base.

A buddy in Salt Lake City did his that way for a ford, he got a bad dose of water and had the truck stall on the hiway. Because he heard me yelling about fuel pressure gauges for years- he saw his plugging up as he drove down the road.
He pulls over, drains some fuel then spins off and dumps the filter on the side of the road, runs his electric pump to refill system. Starts truck, pressure goes up some and he makes U turn back to the fuel station.

He goes in asking for manager and tells people as he goes past- “don’t buy fuel right now, it’s full of water.” Talks to manager, who just took his $100 bill a little bit ago. Starts truck to show how it’s running rough- They pump from his tank into a container after pouring in another filter worth.

Manager has him pump his entire tank into the main fuel tanks at the station. Manager shuts down all pumps- then drives across street and fills a small fuel can to put in his truck tank. Manager gives him $300 cash with apologies He drives across street where the manager put another $100 on a pump for him to fill up. Manager was Super glad it was an old diesel not a new cp style truck.

My recommendation when you have water- drain that tank and at a minimum use the water separator funnel- but even then- the price of a tank of fuel vs replacing ip & injectors makes the safer choice that you just have a bunch on weed killer now.
 
Yep Wouldn't be a bad idea to get a new filter!! I will plan that along with checking the fuel for water. I really hope it's simply my permanent jerry rigging that's the issue LOL

I couldn't imagine what would happen if water even the slightest amount made it past the OEM style filter into the IP
 
Well I think I determined what is happening with my truck! the same thing happened again at the same intersection this morning on the way to work! slowing down from 60 going into the turn lane and the RPM gets really low, starts chugging and almost stalls out. when I noticed it I followed @Will L. recommendation and popped it into neutral. RPM came back. when it was time to take off I switched it back into drive and it was fine the rest if the way to work.

The lockup in the TCC is not releasing!! What do I do now!! This truck uses the TCI aftermarket trans controller and I have not had any issues with it in the past! Though the trans has always had a hard shift from 1st to 2nd since I got it running. plus the PO said it was fully rebuilt back in 2018.
 
Well I think I determined what is happening with my truck! the same thing happened again at the same intersection this morning on the way to work! slowing down from 60 going into the turn lane and the RPM gets really low, starts chugging and almost stalls out. when I noticed it I followed @Will L. recommendation and popped it into neutral. RPM came back. when it was time to take off I switched it back into drive and it was fine the rest if the way to work.

The lockup in the TCC is not releasing!! What do I do now!! This truck uses the TCI aftermarket trans controller and I have not had any issues with it in the past! Though the trans has always had a hard shift from 1st to 2nd since I got it running. plus the PO said it was fully rebuilt back in 2018.
Its just a solenoid inside the transmission pan. Easy enough to change out.
I once had to do one on my 1987 K1500, twenty below and in a snow drift.
It was an easy enough task but that snow and cold was not a nice situation.
That was on a new reman transmission.
The co. Sent over transmission fluid, a new internal wire harness and that solenoid.
They also sent me a check for $150.00 for the troubles. 😹😹😹😹
 
Found the TCC PWM solenoid. placed the order to arrive this Satuday. according to RA I need two of the?? One is for the downshift 3-2.

I am wondering if I should also replace the 1-2 shift solenoid too. I can't find a good quality harness and get it by this weekend so I will just plan on doing the solenoid and see if that helps.

1778773671646.png
 
went ahead and ordered the 1-2 shift solenoid too. figured might as well since I have already replaced the ECP solenoid a while back and it hasn't seemed to fix the hard 1-2 shift. good thing is this pan has a drain plug so I won't make too much of a mess and I can save on the fluid this time!

I used a GM re-usable gasket when I had the pan off last time too so that's a plus. it should still be clean too. it hasn't been too long since I had done this.

1778775451330.png
 
This weekend is going to be fun filled!! I have our friends Mercedes I had already promised to try and fix a power steering leak on, plus bringing the ole'Betsey the dodge ram back up to par for the road for my daughter since her car is out of commission from the hit and run. now the "hope and prayer" trans fix on my 93.
 
Now here's a kicker... as you all know my 93 is styling a TCI EZ-TCU trans controller. Now idk if it works this way with the OEM TCM, but a fella on another thread here was just talking about his TCC lockup not working and found out it was the switch on the pedal.... (you see where I am going with this)

if that switch were to fail but in the opposite way getting stuck on so when I step on the brake the TCM isn't seeing that signal to disengage the TCC lockup. is there other safeguards on there to turn off the lockup when coming to a stop? or can this be my issue too?

@Will L. I know you've worked with the hummer guys that are running this TCU controller. I wonder if it has the "brain power" to use other sensors like the TPS to unlock the TCC.


I need to grab my ohm meter and probe that switch and verify it before opening up the trans!
 
Well trying to probe that switch is a big fail! I thought I would be able to get in there at it but no it's tucked way up in there along with a massive bird nest of wires that I still need to clean up that I never touched since getting the truck! I guess I better just get a replacement switch. I bet it's the factory one from 93 so better to just replace it and hope for the best.
 
It’s been way too long since I had to chase down this issue.
Just because it’s free, ai would start with calling TCI.
They might have a flow chart of diagnostics for you to go through before buying parts.

If they aren’t any help- then it’s time for finding proper diagnostics order.
 
Well I fired the parts cannon on all three. TCC solenoid, 1-2 shift solenoid (not related) and the brake pedal switch. I will have them here in hand this weekend if I need them, otherwise I guess I can return them if not used. ether way I might want to renew the plates on the 95 and have it ready to roll just in case....

That will put 4 vehicles on the "to do" list for this weekend!! at least all the 95 truck needs is license plates and a set of batteries which I can rob from the 93 if I need to HAHA.
 
Your EZ-TCU does not use the brake switch/TCC signal.
The OEM TCM does use that signal to control TCC operation.
Thank you @Glagulator you wouldn't know by chance what signals it uses to disengage the TCC lockup? I haven't connected the handheld display for it yet to verify it's commanding a disengage / release yet. there isn't very much live data that it does show, but iirc it does show a symbol on the screen when lockup is commanded.
 
Well this morning heading to work it tried to do the same thing, only this time a light blip of the accelerator pedal and it unlocked. hmm... maybe the TPS is going wacky or has moved out of adjustment? I need to check that. it's a cable operated TPS from TCI.
 
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