Community Forums

coopcolt · 02-13-2018, 09:25 AM

While towing in Northern Florida, with and ambient temp.
of 85 degrees. My scangauge transmission temp rose to
158 degrees. I have read that I have to add 20 degrees
to this figure to get the TRUE tranny temp.

What are most reading, as a HIGH temp, and when does
it get too high?? Thanks for any input! tenn.vol

Skip426 · 02-13-2018, 09:49 AM

You have to know the type(s) of trans coolers your coach is equipped with, and how they are placed in the cooling stack .
Common routing and placement ,is the trans fluid goes through an oil to water( engine coolant ) cooler, at one end of the radiator , then out through an oil to air cooler . The oil to air cooler, can be in front of the air conditioning condenser, or between the condenser and the radiator.
The placement between the condenser and rad will result in slightly higher temps when the A/C is in use.
Trans fluid type , regular or synthetic , also comes into play when considering , how hot is too hot . Regular fluid 240/250 is too hot , while synthetic will handle another 30/40 degrees.
Some where in the Allison trans section of the forums there is a chart of temps, I'll see if I can track it down.

dieselclacker · 02-13-2018, 09:50 AM

My trans operating temp usually runs 35-40 degrees below the engine coolant temperature. I use 180 degree thermostat in engine. Trans is usually in 150-160 range. Long mountain grades make both both coolant and trans temps rise. I have never seen over 190 degrees on my trans temp regardless. Temps are from my Scan Gage II.

Skip426 · 02-13-2018, 10:15 AM

Here's a manual for your transmission , with fluid temps listed on pages 57/58.

AKIQPilot · 02-13-2018, 03:25 PM

On our Itasca the transmission temp is typically 30-40f lower than engine coolant temp. Running down the road and not towing we typically see 150-160f for coolant temps, just like dieselclacker mentioned above. While towing the temps definitely go up but i have never seen trans temps above 180f. And we tow a lot and fairly heavy.

All temps are from my Scan Gauge II.

CJ7365 · 02-13-2018, 05:25 PM

Quote:

Originally Posted by coopcolt

While towing in Northern Florida, with and ambient temp.
of 85 degrees. My scangauge transmission temp rose to
158 degrees. I have read that I have to add 20 degrees
to this figure to get the TRUE tranny temp.

What are most reading, as a HIGH temp, and when does
it get too high?? Thanks for any input! tenn.vol

Can you please be specific about where you read to add 20 degrees, this is the first time I have heard about that

coopcolt · 02-14-2018, 10:08 AM

Don't remember where I read the add 20 degrees, but it was
most likely 10 of so yrs. ago. And from one of the RV web
forums. .....coopcolt

chertman47 · 02-27-2018, 08:36 AM

Quote:

Originally Posted by Skip426

Here's a manual for your transmission , with fluid temps listed on pages 57/58.

Appreciate the Allison attachment. Thanks

coopcolt · 02-27-2018, 01:07 PM

Thanks a lot of info, dont know if it answers the question
about the scan gauge...anyone?
coopcolt

Arch Hoagland · 02-27-2018, 04:20 PM

Year, make and Model might help....Are you using Transynd?

AKIQPilot · 02-28-2018, 01:44 AM

Quote:

Originally Posted by coopcolt

Thanks a lot of info, dont know if it answers the question
about the scan gauge...anyone?
coopcolt

Well you’re not getting anywhere close to the max recommended trans temp so i dont think you should be too concerned with adding 20 deg to the numbers you are seeing. The max sump temp is 250f and the max to cooler temp is 300. You arent seeing even half of that temp as reported in the OP.

If you start seeing trans fluid temps in the 250 range on your scan gauge then you know something is going on and its time to pull over and let it cool down. Reality is unless you are towing a huge load and are way over gvwr and going up miles and miles of hills you wont see anything close to 250 on your scan gauge.

I tow at max GCWR all the time on the Itasca. Going up and down hills and i cant ever recall seeing over 200f on the scan gauge.

coopcolt · 02-28-2018, 07:02 AM

Thanks everyone, my 02 winnie, with 60K miles.
I am thinking I changed (rotated) the transyn oil
4 times, the last time with Mobil 1.
Every time changed the external filter.

I have never seen the tran. temp over 160 on SG.
Even if I add 20 degrees. that is less than 180.
coopcolt