Mistake #1 I overloaded my truck
BTW this is my 88 K 1500 1/2 ton with a 700R4
I went to get a load of gravel and had the loader operator dump the stuff in.
When I went over the scale, There was over a ton in there ...2200 lb.
I started sweating immediately.
Drove to work... It wouldn't pull Overdrive on the hills, so I put it into 3rd and engaged the manual TCC switch
Mistake #2 was when I got to work. I got distracted by something and forgot to turn off the TCC switch
It disconnects itself when the brakes are on, so I didn't notice
I must have driven my truck fully overloaded up hills, down hills through town, stop / go, for maybe 1/2 hr before I realized I'd forgotten to turn off the switch.

There is no doubt in my mind that I have done some damage by abusing my transmission this way
Yet miraculously it still works.
How much longer is the question
I'm wondering what parts of the internal mechanism suffers the damage when someone does what I did?
I figure that now is a good time to start saving and buying parts, because I have a feeling that I have shortened the life of my 700R4 significantly

Advice? Condolences?

Thank you in advance

 

I don’t know what you have the switch connected to but it is not the converter clutch. And you should never pull or haul anything in OD. If the converter was locked it would kill the motor and if it was locked and was able to slip enough to not kill the engine you would have a converter that would melt through the case.

 

That's interesting
I bought a wiring kit from Bowtie Overdrives that's called a converter lockup wiring kit which operates through the pressure switch inside the trans, and it disconnects when the brakes are applied or when the trans downshifts.
And there's also an auxiliary toggle switch that allows the driver to lock up the converter clutch for hauling when using 3rd gear. That also momentarily opens the circuit when brakes are applied.
When I throw the switch on, the tach shows a decrease of about 200 rpm.
So it appears to be working

 

Yup
I have the same Bow Tie kit in my hopped up 1988 RX7 with a 2004R behind a 350 SBC - I wired in the lockup switch also - plus I added a vacuum switch so when throttle is applied and when vacuum drops it interrupts the circuit and unlocks converter

 

Good deal, you have the correct setup. I took for granted you just tied a switch in the wiring and also ran it through your brake switch. I apologize for not asking more questions. I don’t think you would have caused any undo damage. The engine should have really lugged down if lock up was engaged in stop and go traffic. Check the condition and level of fluid and look for leaking as if the transmission was overheated it would spit fluid out of the vent. Just out of curiosity were you manually shifting or letting the transmission shift itself in D?

 

That's a good idea - Thank You - I'm going to do that, also wire an idiot light to remind me to unlock.

 

I had it in D (notOD)
There was one time when I left it in lockup when I was driving, accidentally, and it was obvious that the trans was behaving differently... That was with the truck empty.
I'm sure that you know what I mean about that... The way it shifts differently when the lockup is on. It didn't stall because of the brake switch disconnect.
I thought that if I ever left the lockup switch on, I'd know by the way it behaves, and I'd be reminded to disengage.

The time I did it with a load in it, it wasn't so noticeable, and I made the mistake of driving around over some hills off road before I realized.

I'm going to remove the pan and have a look when I have some extra time.

The trans is operating normally, presently. My concern is that I caused some premature wear on the internals that will lead to failure at some point.

Thanks for your input