4180E failing

[MIHELA]

There is a temp sensor, that can be seen in a datastream. It is used to go into a hot mode if the trans overheats. It can change lockup and shift points in this mode.

 

[Edward Case]

Are these your personal observations or just regurgitated internet babble? Because I have never personally seen a trans fail after a fluid/filter change.

New fluid dislidges all the sludge deposits and that will plug up passages, another consequence of overdue service.

 

[Edward Case]

On a unrelated note, that harness says it has a temperature sensor. I've wondered if the ECU knows the transmission temperature, but there was just never a guage on the cluster on the GMT400s? Maybe tranny temperature is just used to adjust shift characteristics, etc.? I don't think these trucks go into limp mode if the tranny overheats, right?

But then how is a driver supposed to know what the tranny temp is? Is there a way to add a guage through the ECU? Most common thing I see is an aftermarket guage from the local parts store, which is what I've wanted to do to my '00 OBS K3500...

 

[Edward Case]

I got a code of high trans temp in a 96 explorer, no gauge for it. Trans was mortally wounded at that point.

 

[stutaeng]

I got a code of high trans temp in a 96 explorer, no gauge for it. Trans was mortally wounded at that point.

Were you towing something? I would think that a transmission temp gauge would be mandatory on towing anything above 5,000 lbs on any truck.

At that point your "warning" CEL might as well say "you're screwed!"

 

[Duallylife]

I have a 93 k3500, on the driver side of my trans is a electrical connector with a rubber boot that pushes into the side of the trans right near a black box. I would check that, the connector got smacked off and half unplugged twice on me, once by bent 4wd linkages which you dont have. And once by a idiot dropping my pan for a flush. Caused my trans to jump in and out of gear, shift up and down randomly and sometimes never shift because it doesn't get proper signals, you might be able to snap it back in or you may need to replace, had to do both with mine.

 

[LVJJJ]

Having been towing since 1988 with a 1965 Chevy Van with a 292 stroker 6 and a built TH350, I take trans temp very seriously (still have the van) I had a bung welded into the trans pan and read the temp while towing on one of 9 Autometer gauges. Heat build up in a van where the engine is between the front seats is a major problem. I had the two tranny coolers right behind the grille and was able to keep the temp around 160 to 190 for 90,000 miles. Now with the pristine low mileage (125,000) '94 Suburban I bought in 2016, I had the trans fluid changed by a GMC dealer and at the same time had them weld a bung into the pan and installed an Autometer trans gauge. Last summer we planned an RV trip to Eastern Washington where it can be really hot in the summer so I installed a bigger trans cooler as recommended by someone on this forum. It worked great, it usually ran at 160 to 170 in 100 degree heat on level highways. Got up to around 194 when pulling Stevens Pass and some up and down highways in central Washington on a 105 degree day. Sure glad I installed the guage cause I would have been worried the whole trip that the trans was going to overheat. By pulling the pan, was able to replace the filter. If you tow, you need a gauge.

 

[Andrew7]

I have a 93 k3500, on the driver side of my trans is a electrical connector with a rubber boot that pushes into the side of the trans right near a black box. I would check that, the connector got smacked off and half unplugged twice on me, once by bent 4wd linkages which you dont have. And once by a idiot dropping my pan for a flush. Caused my trans to jump in and out of gear, shift up and down randomly and sometimes never shift because it doesn't get proper signals, you might be able to snap it back in or you may need to replace, had to do both with mine.

I would say this might be close to what is going on with my tranny.