Transmission Issues

[H3nightrod]

So I am currently experiencing a few bugs in my trans thatthe mechanic can't seem to fix. I would take it to another shop but in order tonot pay for a second trans I need to stick with this shop because of the warranty.
So few months back I was on the highway going about 75 mph,I went to pass and trans went into passing gear, once I passed into the nextlane I let off the gas and trans stayed in passing gear. I then tried to acceleratebut no luck the RPMs would just go higher and higher. At around 4000 RPM truck wouldkick like it was slipping. So I pulled over check fluids everything good. Tookit to trans shop under warranty and mechanic found nothing and no codes. Drovefine for about a week, then it did it again, however this time trans blew andonly had 1st and 2nd gear worked. Mechanic took a week to fix it. Truck ranfine for about 30 days. Then all of us sudden went to Pass and did it again, Iwas tempted to keep running it until the trans fell off but instead pulledover. Fluids good no sign of wear. Drove straight to trans shop and it's beenthere for about one month. Mechanic says it seems to do this only when tempsget too hot. I noticed that this happen to me when it was +95. He installed a pressuregauge to test while he drives it around. He stated that it loses pressure whenthe trans get hot. It seems to slip but if you pull over and start over again itwill shift up and down fine. Once you start to build up heat it will start toact up, and if you keep driving it like I did it will toast the trans.
My current set up is 2008 H3Alpha
ARB Snorkel
35" tires
3" Rancho
Airdock intake
Brand new Aluminum radiator (InternalTrans Cooler)

Please feel free to share any thoughts or conclusions tothis mess. Thank you in advance

 

[BIGFRY77]

My first thought was trans cooler being plugged but with a brand new unit that should not be your issue. Maybe thermostat is bad causing radiator to heat to excessive temp and heating up the tranny fluid.

When Caitlin Jenner gets off what does she blow? Tranny fluids...

 

[alrock]

The only thing I can add - and the symptoms don't really match yours - is when my trans was getting hot was when the transmission fluid pump would fail and I would get no movement. Dealer test drove it (probably across the parking lot) and it didn't fail. I drove it a mile from the dealer and it failed again. My primary symptom was simply a transmission that would not grab any gear.

 

[CaseyS]

So how hot is the trans fluid getting?

Where was the radiator changed in this sequence?

 

[rsc]

I wonder if you have a 3rd gear solenoid going out, or there is an issue with the trans wiring harness inside the pan.

 

[H3nightrod]

Wiring harness seems to be fine.
My first trans went out at 75k (rig was almost stock on OEM tires and wheels) and was covered under warranty, from what I remember it was the 3rd solenoid also. So it seems trans failure is common at least in my rig. This would be the 4th trans repair in 130k.

At second failure I was running a e-fan with external cooler for a few month without stock fan. This was a major no-no for me since the E-fan was cooling less than stock causing trans to over heat in my opinion. I then replaced water pump, thermostat, and fan clutch and went back to stock fan keeping external trans cooler. After doing all these upgrades I noticed OEM radiator was leaking and external trans cooler didn't look to well either. I then pulled the trigger on the aluminum duel core radiator with internal cooler and set it up that way. Still have a few issues when its +95, for example I sat at the drive thru at Chase bank and temps got above 3/4 line (I thought these issues would disappear with new aluminum unit), then I let my rig sit on my drive way with AC on for 40 min, temps almost redlined. I opened the hood (hood was EXTREMELE HOT) with engine on to see how fast temp would drop and within five minutes temps went below 3/4. Thinking of moding hood louver for actual ventilation.

Is there any way that the radiator temps are causing the trans oil to heat way over its limits causing loss of pressure? Could pressure loss be from mechanic using wrong trans oil?

Thanks for all the input and again sorry for the rambling off but my rig has been in the shop for 4 weeks and its frustrating.

 

[Woodtick]

You need to look into why your 3 is running so hot and fix that problem first.

 

[GreatDaneHummer]

Ever thought about just doing a full trans rebuild kit from PATC? Then not worry about it for a long time? That trans guy doing all this work with no results can't be cheap.