High Transmission Temps

[DrunkenChewbacca]

Hello Folks!

Just joined the Forum, I am a member on the GXOR group on FB. This will be a little winded but please hear me out

I purchased my 06' GX470 last October with 225k miles. Before that, I owned a 19 Tacoma TRD OR. I was able to sell that with 51k miles for what I got it brand new and use the extra money to buy my GX outright and some mods. The owner told me he had to change out the radiator due to a crack between the transmission section and radiator section, I looked at the radiator and everything looked ok, no milky fluid or anything. I bout it for recreational purposes and really don't drive it.

Fast forward to April this year, I took my GX to the beach for a 3-day campout, roughly 8 miles down the beach I got the A/T Oil temp light. I immediately pull off the patch and let it cool down. While cooling I pulled up some forums and it said I shouldn't be in D, but rather 2nd gear or something, I wasn't sure because my Tacoma was manual and a pig so naturally driving through deep sand, I was in 2nd gear just ton have some kind of power. I also noticed that the transmission will not always go into 5th gear, like I will be going 60-70 and it will be around 2300-2400 RPMs, I am running 33s so maybe thats throwing it off a little. When I got home, I did the drain and fill using AISIN ATF0WS fluid. I figured AISIN brand would be fine sense they make the transmissions, its WS and also a good price. I also purchased a scangauge II to read transmission temps during the process. During the fluid change, it seemed to flow fine, sometimes off the start it would spit it out, maybe air in the system, but it would drain fine with the engine running. After doing the drain and fill, running the transmission to temp (above 120F), and checking the overflow while running, only a little fluid came out, so it seems to be topped off properly. I am still getting temps around 200-210 degrees and 5th gear still doesn't engage when I think it should, all other gears seem to be strong.

SO...... I'm at a loss right now, I don't know if I have a blockage somewhere, I would this not sense the drain and fill went alright. Did the last owner buy a cheap radiator and maybe its causing this problem? I might pull the hoses off this weekend and look form any blockages.

 

[vipergrhd]

Does it have an Aux cooler after the radiator? 200-210 is still normal temp. for an auto trans. but since you have a 5th gear shift issue I would take it to a transmission shop and have them look into it. If you do have an Aux cooler maybe try back flushing the unit there are flush in can ready to use for auto trans.

 

[DrunkenChewbacca]

Does it have an Aux cooler after the radiator? 200-210 is still normal temp. for an auto trans. but since you have a 5th gear shift issue I would take it to a transmission shop and have them look into it. If you do have an Aux cooler maybe try back flushing the unit there are flush in can ready to use for auto trans.

Does have the Aux cooler after the radiator, that's where I serviced the transmission for the drain and fill.

 

[vipergrhd]

What type is the cooler? Tube and fin or plates and fin? The tube and fin you could use compressed air to blow out but the plate and fin needs to be back flushed to push out any sediments also check the cooler in the radiator use low air pressure to begin.

 

[DrunkenChewbacca]

What type is the cooler? Tube and fin or plates and fin? The tube and fin you could use compressed air to blow out but the plate and fin needs to be back flushed to push out any sediments also check the cooler in the radiator use low air pressure to begin.

Plates and fin type. Ill have to check. Seemed to be flowing when I disconnected it for the drain and fill.

 

[McDuff123]

No help here on the issue with 5th gear, but a thought on the transmission temps.
When you programmed your “X-guage” parameters for trans temp, I’m wondering if you used the codes that display temp at the torque converter, rather that at the pan.
TC temps are reliably hotter than pan temps. One way to tell is by noting how quickly the temp rises and falls. TC temps move quickly, depending on load and if the TC is locked or not. Pan temps move much more slowly and through a narrower range.
Below are codes for TfT (Transmission Temp, fahrenheit ) for Gx470’s, from the ScanGauge site.
The top 2 both work…one displays TC, and the other displays pan.
I can’t quite remember, but I *think* the top code is TC.
Maybe if you monitor your pan temps, it will give you more peace of mind, or at least more data.
Good luck and please report back.

 

[GXO]

Not shifting to 5th or not getting torque lockup? Two very different things.

 

[DrunkenChewbacca]

Not shifting to 5th or not getting torque lockup? Two very different things.

So Before all this happened, which I accidently left out, sometimes when you come to a stop, it feels like its still 'grabbing' Like it wants to just go, Vs. when you let off the gas, it just creeps. I am wondering if the TC could be giving me issues.

 

[DrunkenChewbacca]

No help here on the issue with 5th gear, but a thought on the transmission temps.
When you programmed your “X-guage” parameters for trans temp, I’m wondering if you used the codes that display temp at the torque converter, rather that at the pan.
TC temps are reliably hotter than pan temps. One way to tell is by noting how quickly the temp rises and falls. TC temps move quickly, depending on load and if the TC is locked or not. Pan temps move much more slowly and through a narrower range.
Below are codes for TfT (Transmission Temp, fahrenheit ) for Gx470’s, from the ScanGauge site.
The top 2 both work…one displays TC, and the other displays pan.
I can’t quite remember, but I *think* the top code is TC.
Maybe if you monitor your pan temps, it will give you more peace of mind, or at least more data.
Good luck and please report back.
View attachment 3027394

Great info. I will see what I have programmed in and get back.

 

[DrunkenChewbacca]

No help here on the issue with 5th gear, but a thought on the transmission temps.
When you programmed your “X-guage” parameters for trans temp, I’m wondering if you used the codes that display temp at the torque converter, rather that at the pan.
TC temps are reliably hotter than pan temps. One way to tell is by noting how quickly the temp rises and falls. TC temps move quickly, depending on load and if the TC is locked or not. Pan temps move much more slowly and through a narrower range.
Below are codes for TfT (Transmission Temp, fahrenheit ) for Gx470’s, from the ScanGauge site.
The top 2 both work…one displays TC, and the other displays pan.
I can’t quite remember, but I *think* the top code is TC.
Maybe if you monitor your pan temps, it will give you more peace of mind, or at least more data.
Good luck and please report back.
View attachment 3027394

Just tried all of those codes and only the top one works. Last 3 don't display anything.

 

[GXO]

I wager you may have a failing torque converter as if you had a solenoid for shift causing issues you would have codes.

I assume you got all the codes from the various ECUs.

 

[DrunkenChewbacca]

I wager you may have a failing torque converter as if you had a solenoid for shift causing issues you would have codes.

I assume you got all the codes from the various ECUs.

Yeah. Nothing is popping up. I bet the TQ is on the way out. I'm going to do another inspection tomorrow and check all the lines.

 

[GXO]

Do you have a shudder on long steady hill climbs?

 

[DrunkenChewbacca]

Do you have a shudder on long steady hill climbs?

Not at all. No slipping or shuddering. Everything seems to be smooth

 

[GXO]

Do you have pictures of the radiator? Depending on the make of the radiator it may have eliminated the cooling loop for the transmission. If you could use the pump to swap the fluid I doubt you have a blockage because it would have to be in the valve body for that cluck pack pathway and solenoid and would throw a code.

I suspect you could have insufficient cooling in the front. Do you have an aux cooler? May want to add one.

 

[DrunkenChewbacca]

Do you have pictures of the radiator? Depending on the make of the radiator it may have eliminated the cooling loop for the transmission. If you could use the pump to swap the fluid I doubt you have a blockage because it would have to be in the valve body for that cluck pack pathway and solenoid and would throw a code.

I suspect you could have insufficient cooling in the front. Do you have an aux cooler? May want to add one.

Yeah the last owner changed the radiator and could be a cheapo one. I'll take pics tomorrow. Also yes I have the small Aux cooler and it's hot to the touch when in operation. The radiator does have the in and out for the transmission lines and are hooked up. Do you know much about the electric cooling fan that's in the front of the condenser unit?

 

[McDuff123]

Do you have pictures of the radiator? Depending on the make of the radiator it may have eliminated the cooling loop for the transmission. If you could use the pump to swap the fluid I doubt you have a blockage because it would have to be in the valve body for that cluck pack pathway and solenoid and would throw a code.

I suspect you could have insufficient cooling in the front. Do you have an aux cooler? May want to add one.

Good point about an aftermarket radiator not having an internal transmission cooler loop.
When I was shopping for my new Denso radiator, I came across several off-brand options that did not have the internal loop.
Even with that as part of my cooling circuit, I run a stand-alone Transmission cooler.
Trans temps so far, pulling a teardrop trailer (2550 lbs) over our mountains here, have not exceeded 190.
Good luck OP…

 

[GXO]

Yeah the last owner changed the radiator and could be a cheapo one. I'll take pics tomorrow. Also yes I have the small Aux cooler and it's hot to the touch when in operation. The radiator does have the in and out for the transmission lines and are hooked up. Do you know much about the electric cooling fan that's in the front of the condenser unit?

That is for the condenser when you have rear AC. Not present on non-third row GXes. It is related to AC not transmission. If you have the ports in the radiator it likely has the loop. I always add a much larger transmission cooler. It helps a lot. Mine runs at 190 on the button most of the time even when towing. If I lock up the torque converter it goes to 168-177. I upgrade my GX transmissions to the Nomad HD valve body as well.

 

[DrunkenChewbacca]

That is for the condenser when you have rear AC. Not present on non-third row GXes. It is related to AC not transmission. If you have the ports in the radiator it likely has the loop. I always add a much larger transmission cooler. It helps a lot. Mine runs at 190 on the button most of the time even when towing. If I lock up the torque converter it goes to 168-177. I upgrade my GX transmissions to the Nomad HD valve body as well.

Got a temp gun from work. Going to shoot temps this weekend. Maybe I should add a larger cooler

 

[DrunkenChewbacca]

That is for the condenser when you have rear AC. Not present on non-third row GXes. It is related to AC not transmission. If you have the ports in the radiator it likely has the loop. I always add a much larger transmission cooler. It helps a lot. Mine runs at 190 on the button most of the time even when towing. If I lock up the torque converter it goes to 168-177. I upgrade my GX transmissions to the Nomad HD valve body as well.

So. Shot some temps and really only see a 5-7 degree drop at the line leaving the smaller aux cooler.. plumbing looks all correct but 7 degree drop going from two coolers sounds off. I noticed that the radiator has a 8in Long by 3in wide indentation in the radiator behind the ac condenser. I have a gut feeling that the radiator might be defective or something. May look into getting a replacement.