A343F Trans & ScanGauge II what are your temp readings? (2 Viewers)

[flintknapper]

If you watch the scan guage temp, the trans temp goes way up if you a running a steep hill in too hgih of a gear (even when in drive) or in high range. You'll also notive the factory coolant temp guage sucks. It won't budge between 175-215

Yes, factory coolant gauge (non-modified) in both the 80 series and 100 series has a big 'dead spot' in it.
Well known to most MUD members. That is the reason I put a ScanGauge in both of my vehicles to start with.

But for my 80 series...I had to do something different in order to monitor the trans temp.

The Oil pressure gauge (factory) is another thing that would lead one to believe they have little to no oil pressure at idle. Just some of the well known quirks about these vehicles.

The Trans temperature will rise anytime the Torque Converter is not locked. Doesn't matter if you are going uphill or not...though that makes things worse.

 

[flintknapper]

Update: Got back from my trip today. Not quite 600 miles (total).

LX did great. On the way to my destination...it was afternoon driving...so ambient temps were the highest for the day (about 85-88°F).

On the highway... coolant temps were 188-190 and the transmission stayed at 123-125° F.

Left early this morning to come back (ambient in the low 50's) coolant temp the same, but trans temp 116-119° F.

I was very happy with those numbers and now am wondering how long we had been driving around with the transmission cooler plugged.

I would never have known there was an issue if I hadn't installed the ScanGauge and punched in the Xcode for a trans temp readout.

Still can't believe it was a 'shipping plug' that had the line blocked or imagine how it got there.

But all is good now.

 

[LuisJr]

Reviving a thread.

I was hitting a trail recently and noticed my trans temps climbed and stayed around the 194-198 degree range. Slow climbing in first gear, less than 6-7mph. Temps were in the 90 degree range in Santa Clarita that day. As soon as we picked up speed in the flatter spots, seemed to help out and get the temps closer to 186-192. I'm guessing a mixture of airflow and being above the slip of the converter. The engine coolant temps stayed right under 200 degrees.

What type of trans temps do you guys see out on the trails??

Thanks Luis

 

[flintknapper]

Will have a chance to monitor my Transmission temps again in the next few days. Heading back to Austin to visit with family and friends. Predicted high temps the next few days (ambient) 102° F. So a bit hotter than our last trip.

I will also have the LX loaded down more heavily. Be interesting to see what it does.

 

[AimCOtaco]

I have noticed mine as high as 200F in similar situations @LuisJr .
One thing that will help, especially for general 'wheeling is to run in 2nd with the 2nd start mode engaged... it locks the trans in 2nd; stays cooler, and doesn't shift at all. I find running 2nd start and 2nd works for moderate grade trails at a least when not crawling over stuff, then I just drop into low for the obstacles and/or steeper stuff.

 

[LuisJr]

Exactly when I left it in just 2nd, it would shift back and forth and temps were at 200 peak. Once I just held first gear because of how slow we were going, it dropped 5-7 degrees. On the way down we were close to 10mph and it was well below the temps I mentioned.

 

[Greenbean]

When we are driving around the beach on Ocracoke I just leave it in low gear or 1st, and that is what keeps my trans temps the lowest.

Lots of friction in the soft sands for sure.

 

[Ayune]

Briefly saw these numbers yesterday during my stop & go commute with AC on. Most of the time my tranny temps are around 150-175 with coolant right at 200. I’m planning a tranny flush soon, trying not to worry too much...

 

[flintknapper]

Just got back from an out of town trip. Similar ambient temps.

On the highway my coolant temp would be a steady 188° F. and tranny temp about 132-135° F.

In the Houston traffic coolant temp 191° F. and tranny as high as 155° F.

Yours is not worrisome...but could be better. There are differences in altitude to account for also though.

 

[LuisJr]

Just got back to Ventura County from the Jeep/TruckFest in Long Beach. I noticed the warmer temperatures in the 85-95 degrees pushes my trans temps to the 170-180 degree range, but that's also on the 405 lugging in OD. Ive made it a habit to turn off OD on grades. Stop and go traffic in warm temps is about 150s - 170s. But as soon as ambient temps drop in the 60s, it's typically in the 120-140 range.

I thought about adding a larger cooler, but not sure if it would make a difference. I don't see the temps I'm seeing as being detrimental to life though. Seems like a normal range. It's a good baseline for when I do the trans fluid flush in the next week or so.

I think it would be nice to keep it under 160 under load/inclines. Seems like over 160ish it starts to feel a little sluggish but it also feels the same type of sluggish when it's around 180-190 too. So I don't think it's out of its range at all.

Ok gym time lol

Luis

 

[TheForger]

These readings were taken after about 1.5hrs of driving on the interstate while the cruise control was set at 80mph right around 2800rpms with 104* ambient temps.

 

[flintknapper]

Those of you showing slightly higher trans temps than mine...did you use the same Xcode to set up your ScanGauge?


TXD: 686AF101B4

RXF: 044105B40000

RXD: 2808

MTH: 00090005FFD8

 

[TheForger]

Those of you showing slightly higher trans temps than mine...did you use the same Xcode to set up your ScanGauge?


TXD: 686AF101B4

RXF: 044105B40000

RXD: 2808

MTH: 00090005FFD8

That's the exact code that I found in another thread on here and was the only code that would allow me to read the trans temps for my truck. During my initial XCode setup I initially entered another code for what I thought was for the A343F trans but it turns out it was for the A750F so it didn't work. Just went out to my truck to confirm those are the correct TXD, RXF, RXD, & MTH XCode.

What are your (or anyone else's opinions) on my readings?? Like I said I drove 1.5-2hrs at 80 on cruiser control but it was 104* ambient temps +/- 2 degrees so I anticipated it would be in the higher numbers. I did a DIY full trans fluid exchange back around 10/20/17. I have an upcoming 3000+mi round trip from AR to CO July 25-Aug 9, so I'm debating on doing just a simple drain and fill before departure.

 

[trdcorolla]

That's the exact code that I found in another thread on here and was the only code that would allow me to read the trans temps for my truck. During my initial XCode setup I initially entered another code for what I thought was for the A343F trans but it turns out it was for the A750F so it didn't work. Just went out to my truck to confirm those are the correct TXD, RXF, RXD, & MTH XCode.

What are your (or anyone else's opinions) on my readings?? Like I said I drove 1.5-2hrs at 80 on cruiser control but it was 104* ambient temps +/- 2 degrees so I anticipated it would be in the higher numbers. I did a DIY full trans fluid exchange back around 10/20/17. I have an upcoming 3000+mi round trip from AR to CO July 25-Aug 9, so I'm debating on doing just a simple drain and fill before departure.

I'm back reading this thread because of my transmission temp concerns. On bumper to bumper traffic or driving in the street's my temp is 145-170ish. On the freeway drafting with another car at speed, it's around 150-160ish, not drafting it's around 140-150ish, so i'm in line with your freeway numbers. On the street's on a long incline is where my temp would shoot to 180-200 for a short time then back down. I cleaned my ATF cooler and the temps stayed the same. I'm hoping that's normal per @Kofoed from his response (reply earlier in the thread.

 

[flintknapper]

I'm back reading this thread because of my transmission temp concerns. On bumper to bumper traffic or driving in the street's my temp is 145-170ish. On the freeway drafting with another car at speed, it's around 150-160ish, not drafting it's around 140-150ish, so i'm in line with your freeway numbers. On the street's on a long incline is where my temp would shoot to 180-200 for a short time then back down. I cleaned my ATF cooler and the temps stayed the same. I'm hoping that's normal per @Kofoed from his response (reply earlier in the thread.

That all sounds very much normal and well within specs.

As for increased temps on inclines...ANY condition that results in the torque converter not being locked up will increase the fluid temp. That is not to say that torque converter lock-up is always desirable.

But generally speaking...an increase in trans temps when unlocked is to be expected. Once the engine load is reduced and you return to lock-up the fluid temp will gradually recover (usually within 10 minutes unless heat soaked).

 

[trdcorolla]

That all sounds very much normal and well within specs.

As for increased temps on inclines...ANY condition that results in the torque converter not being locked up will increase the fluid temp. That is not to say that torque converter lock-up is always desirable.

But generally speaking...an increase in trans temps when unlocked is to be expected. Once the engine load is reduced and you return to lock-up the fluid temp will gradually recover (usually within 10 minutes unless heat soaked).

Thanks, I also read in another thread the A/T temp light goes off at 230 (that's assuming the FSM ATF sensor test at 230F is when the light goes off).

 

[calskibum]

In post #3, flintknapper mentioned about checking ATF fluid level when temp is between 115 and 130. At this temp, should the ATF level be at the hot mark or just somewhere between the hot and the cold marks on the dipstick? Somehow I've always found that making sure there is the proper level of ATF in my LC frustrating, not knowing for sure at what temp the fluid is supposed to be at the hot mark. Somehow I was under the impression to check the ATF level when the temp is somewhere around high 150s to low 160s, but in reading flintknapper's post, looks like I'm way off. I think the manual says that the fluid level is supposed to be at the hot mark when the transmission is at the normal operating temp, but it doesn't say what the normal operating temp is. Any ideas? I have a 99 LC in case that makes a difference.

 

[flintknapper]

In post #3, flintknapper mentioned about checking ATF fluid level when temp is between 115 and 130. At this temp, should the ATF level be at the hot mark or just somewhere between the hot and the cold marks on the dipstick? Somehow I've always found that making sure there is the proper level of ATF in my LC frustrating, not knowing for sure at what temp the fluid is supposed to be at the hot mark. Somehow I was under the impression to check the ATF level when the temp is somewhere around high 150s to low 160s, but in reading flintknapper's post, looks like I'm way off. I think the manual says that the fluid level is supposed to be at the hot mark when the transmission is at the normal operating temp, but it doesn't say what the normal operating temp is. Any ideas? I have a 99 LC in case that makes a difference.

^^^^^^ Good catch. I think that figure stuck in my head from a previous discussion concerning a A750F transmission (sealed trans, no dipstick). I have deleted that from my post.

Both of my manuals (80 and 100 series) that relate to the A343F transmission state to check the transmission fluid with both the engine and transmission at 'normal' operating temperature and then go on to suggest that the transmission fluid should be between 158°F - 176°F. The level on your dipstick should be at the 'hot' mark with engine idling, parked on a level surface.

The FSM goes on to say that when doing any mechanical or pressure testing...that 'normal' fluid temp should be between 122°F - 176°F.

So...my guess is they want you to check your fluid level when it is at the high end of 'normal' operating temps.

I would have a hard time getting either of my vehicles A343F transmissions to 160°F unless it was city driving on a very hot day and I pulled over immediately to check the level. Both of mine usually run about 145° and when I pull over and park (idle) they will cool down to 130ish even in the summertime.

I check mine after the engine has reached 186-190° for 10 minutes. I shift the transmission through all the gears one time...then check the level. That is not FSM protocol...but has worked well enough for me.

 

[calskibum]

^^^^^^ Good catch. I think that figure stuck in my head from a previous discussion concerning a A750F transmission (sealed trans, no dipstick). I have deleted that from my post.

Both of my manuals (80 and 100 series) that relate to the A343F transmission state to check the transmission fluid with both the engine and transmission at 'normal' operating temperature and then go on to suggest that the transmission fluid should be between 158°F - 176°F. The level on your dipstick should be at the 'hot' mark with engine idling, parked on a level surface.

The FSM goes on to say that when doing any mechanical or pressure testing...that 'normal' fluid temp should be between 122°F - 176°F.

So...my guess is they want you to check your fluid level when it is at the high end of 'normal' operating temps.

I would have a hard time getting either of my vehicles A343F transmissions to 160°F unless it was city driving on a very hot day and I pulled over immediately to check the level. Both of mine usually run about 145° and when I pull over and park (idle) they will cool down to 130ish even in the summertime.

I check mine after the engine has reached 186-190° for 10 minutes. I shift the transmission through all the gears one time...then check the level. That is not FSM protocol...but has worked well enough for me.

Thanks, flintknapper, for the info. I too find my transmission temp cools quickly after parking and shifting through the gears, which adds to my perception of the difficulty in making sure my ATF is at the proper level. I'm glad that I'm not the only one.

 

[nissanh]

Mine stays around 120 F even outside is at 95 F. This is all flat west TX driving with AC on. I clean the fins of trans cooler often.
The fluid level stays above hi on cold range (but below low on hot range) when the engine is cold and idling. Trans oil has a very high coefficient of expansion.