Allison operating temps - Printable Version

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+--- Thread: Allison operating temps (/showthread.php?tid=732)

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RE: Allison operating temps - Richard - 06-02-2026

The gauge on the dash for trans temp has a sensor in the bottom outlet of the trans cooler. The trans cooler is an integral part of the radiator on your coach. Open the hatch, look at lower left at bottom of radiator.

Are the temps you are quoting coming from the VDO gauge on the dash, OR a digital signal feeding a VMSPC, Bluefire, or Scangauge?

The digital temp will come from a sensor in the transmission.

The cooler in the space above the rear axle is for hydraulics.

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RE: Allison operating temps - [email protected] - 06-02-2026

(Yesterday, 03:31 PM)Richard Wrote:  The gauge on the dash for trans temp has a sensor in the bottom outlet of the trans cooler. The trans cooler is an integral part of the radiator on your coach. Open the hatch, look at lower left at bottom of radiator.

Are the temps you are quoting coming from the VDO gauge on the dash, OR a digital signal feeding a VMSPC, Bluefire, or Scangauge?

The digital temp will come from a sensor in the transmission.

The cooler in the space above the rear axle is for hydraulics.

Thanks for clarifying Richard, just have not spent enough time under mine tracing the lines to see what was going to what. 

Not to get too far off topic but do you know what controls the fans on the hydraulic cooler? Is it the temp sensor in the hydraulic tank? 

I will have to look at mine to see where the transmission cooler lines are running.

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RE: Allison operating temps - Richard - 06-02-2026

Jeff , I do NOT know what turns the hyd fans on and off.

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RE: Allison operating temps - [email protected] - 06-02-2026

(Yesterday, 04:32 PM)Richard Wrote:  Jeff , I do NOT know what turns the hyd fans on and off.

10-4, I will have to go hunting. Just want to make sure they are working.

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RE: Allison operating temps - whited44 - 06-02-2026

(Yesterday, 03:31 PM)Richard Wrote:  The gauge on the dash for trans temp has a sensor in the bottom outlet of the trans cooler. The trans cooler is an integral part of the radiator on your coach. Open the hatch, look at lower left at bottom of radiator.

Are the temps you are quoting coming from the VDO gauge on the dash, OR a digital signal feeding a VMSPC, Bluefire, or Scangauge?

The digital temp will come from a sensor in the transmission.

The cooler in the space above the rear axle is for hydraulics.

Hi Richard. Those numbers are coming from the BlueFire.

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RE: Allison operating temps - Richard - 06-03-2026

Dennis have you changed filters and replaced fluid with new transynd? If not that would be my first move.

I typically would trust a digital input but since you asked where the sensor was located I might infer you don’t trust the sensor. Easy enough to shoot the upper inlet pipe to the cooler with an IR gun to cross check

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