What transmission temp is normal?

[DavidWSnow]

Have 2005 Inspire with a 400 HP Cat C9. While driving thru "rolling hills" at 55-60 MPH the trans. temp was between 215 and 230 after sever. Hours of driving. I have Transynd for fluid. Later after driving hru a town and driving at 45 on a small local road it dropped to 190-200.

What is a normal temp?

[2 Stroker]

Originally Posted by DavidWSnow

Have 2005 Inspire with a 400 HP Cat C9. While driving thru "rolling hills" at 55-60 MPH the trans. temp was between 215 and 230 after sever. Hours of driving. I have Transynd for fluid. Later after driving hru a town and driving at 45 on a small local road it dropped to 190-200.

What is a normal temp?

David
I have never seen temp that high going down the road doing 62mph. I have the SilverLeaf and that is what I go buy. In town stop & go the temps will come up then I go into N so if you want real number look at something like the SilverLeaf or, not my bag SanGauge D. Have you check the trans level after service
Checking Fluid Level with the Keypad
The following procedure will allow you to check your transmission fluid level from inside the vehicle, and it is also more accurate than checking via the dipstick.
To enter the transmission oil level display mode, press the UP and DOWN arrow buttons simultaneously on the mode selector. A two-minute countdown begins when the following conditions are met:
Engine is at idle
Transmission sump oil is at operating temperature
Transmission output shaft has stopped
Transmission is in neutral
Oil level sensor is functioning properly
The display should show *8 and then count down to 0. Note that it will take two minutes to complete this countdown. During the countdown, the display flashes and a count (8,7,6,5,4,3,2,1) occurs reducing by one digit every 15 seconds.
NOTE: Failure to meet any of the above conditions will stop the two minute countdown. The shift selector will then display one of the following Oil Level Codes to show the reason for the countdown interruption. The countdown will resume where it stopped once all conditions have been met. Shift selectors with single digit display will display the codes one digit at a time. Shift selectors with two digit displays will display the codes two digits at a time.
OIL LEVEL CODE
CODE DESCRIPTION
oL 0X
Setting time too short
oL 50
Engine RPM too low
oL 59
Engine RPM too high
oL 65
Neutral not selected
oL 70
Sump fluid temperature too low
oL 79
Sump fluid temperature too high
oL 89
Output shaft rotation detected
oL 95
Oil level sensor failed

After the two minute countdown, the shift selector displays the oil level data as in the following examples:
OIL LEVEL READINGS
MEANING OF READINGS
o, L, o, K
Fluid level is correct
o, L, L, o, 1 or OL, LO, 01
Fluid level is 1 quart low
o, L, H, 1 or OL, HI, 01
Fluid level is 1 quart high

To exit the oil level display mode, press the NEUTRAL button or simultaneously press the UP and DOWN arrows twice.
2 stroker

[Papa_Jim]

It's hotter than I would like to see it, but I don't think you've done any harm.

Here's what Allison says about it:

'The transmission is considered to be overheated when any of the following temperatures are exceeded:

Sump fluid 250 degrees F
Fluid to Cooler 300 degrees F
Retarder out fluid 330 degrees F

If the transmission overheats during normal operations, be sure the fluid level is correct in the transmission.'

If the fluid level is OK, then you might want to check the transmission cooling fan. I'm not familiar with the transmission cooling system on your coach. If the cooling fan is hydraulic, check the hydraulic fluid level.

Jim

[Mac99]

Based on your descriptions, I think you have
something wrong. The temps are not normal. I agree
that they don't indicate damage, but you need to
find out what is causing the abnormality. And
I think it is an urgent issue.

[rtz]

[rtz]

Post a pic of your current transmission cooler. You may be able to swap it out for a bigger one.

You want a "bar and plate" style and not the older "finned tube" style.

[Steve Ownby]

Originally Posted by DavidWSnow

Have 2005 Inspire with a 400 HP Cat C9. While driving thru "rolling hills" at 55-60 MPH the trans. temp was between 215 and 230 after sever. Hours of driving. I have Transynd for fluid. Later after driving hru a town and driving at 45 on a small local road it dropped to 190-200. What is a normal temp?

Is this a new to you coach and this is your first observation of the transmission temp, or is this a change in observed temps? Do these temps come from the standard dash gauge? Dash gauge set ups are notoriously unreliable. I recommend investing in an engine/transmission monitoring system that you can see while underway. Silverleaf is a good one but there are others. You first need to know what the real temps are and these systems take the info from the engine ECM rather than the dash system.

The temps you are seeing will not cause damage particularly since you are running Transynd but they cover a pretty wide range for fairly un demanding conditions. Those 215-230 temps should only be occurring under demanding conditions. The torque converter is the most heat producing component in the Allison. If your transmission is not locking the torque converter it could explain the temp fluctuations.

[Smitty77]

Following up on Steve's post. If the rolling hills speed results in hunting between 5th and 6th, this does work the converter. In those cases, a manual downshift to 5th, may be the best overall for engine and trans.

Concur on validating fluid level, and accuracy of reported temps.

Please let us know what you determine, and best of luck,
Smitty

[DavidWSnow]

When I arrived I checked the tranny fluid level from the shifter pad. It wa OK. This morning I checked it from the dip stick and for the first time since I bought it last month. It was showing 4" above the "cold fill" line. Now I am more confused than before,

[jamesrxx951]

Originally Posted by rtz

These charts are not accurate of the transmissions used in this era. Many newer transmissions operate in the 200-220F range now. With the constant strive for better emissions and MPG, fully syn transmission fluids and high transmission fluid operating temps all aid in this. You would need a chart for each specific transmission or fluid type used.

[Steve Ownby]

Originally Posted by DavidWSnow

When I arrived I checked the tranny fluid level from the shifter pad. It wa OK. This morning I checked it from the dip stick and for the first time since I bought it last month. It was showing 4" above the "cold fill" line. Now I am more confused than before,

Hey David,

Allison really wants you to rely on the shifter pad electronic level check. If you want to check cold here is the procedure:

cold check may be made after initial start-up and the presence of transmission fluid has been confirmed (the sump fluid temperature is then typically 16°–49°C (60°–120°F). To perform a COLD CHECK, do the following:
1. Start the engine and run it at idle (500–800 rpm) in N (Neutral) for about one minute.
2. Shift to D (Drive) and then to R (Reverse) to clear the hydraulic circuits of air.
3. Shift to N (Neutral) and leave engine at idle.
4. Move the vehicle to a level surface, put transmission in N (Neutral), and
set the parking brake.
5. With the engine idling (500–800 rpm), shift to D (Drive) and then to
R (Reverse) to clear air from the hydraulic circuits.
6. Shift to N (Neutral) and leave engine at idle.
7. Remove the dipstick and wipe it clean. Insert the dipstick into the fill tube, pushing down until it stops.
8. Remove the dipstick and observe the fluid level. If the fluid on the dipstick is within the COLD CHECK band, the level is satisfactory. If the fluid level is not within this band, add or drain fluid as necessary to bring the level within the COLD CHECK band.

[Dale C]

Some of the Inspires, including my 2005, had the sensor for the trans temp gauge misplaced in the return from torque converter. This will definitely show a quick temperature increase when idling in gear, and in my case shows temps significantly higher than what the trans computer is reading. I would verify what your control computer is reading prior to going too wild with repairs. There are multiple devices that will tell you what the computer is reading, including the SilverLeaf and ScanGauge devices.

I was very concerned when I first noted the temps were indicating high, that's one sure way to shorten the life of the Allison. I have learned that I needed to increase my speed a little to keep the transmission in 6th gear in rolling hills, which resulted in lower temps and better mileage too. I do still use the stock gauge temps to help control the transmission temperature. Shifting to neutral while stopped, even for extended stops at traffic lights helps the idling increases.

[Smitty77]

Originally Posted by Dale C

Some of the Inspires, including my 2005, had the sensor for the trans temp gauge misplaced in the return from torque converter. This will definitely show a quick temperature increase when idling in gear, and in my case shows temps significantly higher than what the trans computer is reading. I would verify what your control computer is reading prior to going too wild with repairs. There are multiple devices that will tell you what the computer is reading, including the SilverLeaf and ScanGauge devices.

I was very concerned when I first noted the temps were indicating high, that's one sure way to shorten the life of the Allison. I have learned that I needed to increase my speed a little to keep the transmission in 6th gear in rolling hills, which resulted in lower temps and better mileage too. I do still use the stock gauge temps to help control the transmission temperature. Shifting to neutral while stopped, even for extended stops at traffic lights helps the idling increases.

Dale - You are the third Inspire C9 (assume) Allison owner I've heard of that has had good results in those rolling hills by either speeding up a bit to retain 6th, or if not safe, manually downshifting to remain in 5th to avoid the heat build up from the hunting of back and forth shifts. (I do this in our ISL30 too, as why not help the transmission with what the computer between the ears has registered to be the terrain ahead. Allison and CAT/Cummins computers are reactive, and thus not as effective as the pro-active down shifting or speeding up a bit when practical.)

OP - The Scan Gauge would be your least expensive method of validating the temps that your Allison computer is seeing too. The needle gauges may not be accurate, and as Dale commented, some Inspires may have misplaced temp sensors.

You should have transyn, and it is going to take more of a beating while still properly protecting your trans.

It is worth getting the actual temps to validate, as you may not have a real problem. Even so, the tips on driving for the condition are still valid.

Best of luck, and please close the loop back and let us know what you find out,
Smitty

[Dale C]

Yes Smitty, my Insprire is the C9. Thanks for chiming in also. The speed increase wasn't huge, I went from cruising at 58-60 to 63-65 and eliminated the vast majority of the downshifts. Of course when it's safe, and still below the limit. When I do need to slow down, manual downshift to 5th seems to help with heating also.