Allison Automatic Operating Temperature

[Stormcloud]

This was mentioned in another thread. So as not to hijack it, here goes.

I have a self-installed MT 654 Allison  in my 8v71 powered MCI. The transmission is cooled by a large Hayden cooler, single pass design.  I installed 2 electric fans on the cooler that can be manually switched, but I have never seen a transmission temperature, measured at the transmission outlet line, higher than 220F. The transmission normally operates around 140F on flat level ground at highway speed, and does occasionaly creep up to 180F in stop-and-go city driving.

3 years now and about 20,000 miles with this configuration. So, here's my questions....

Any problems with operating this transmission at these temperatures 140F-180F ?

What would be the maximum operating temperature I should permit before I pull over??

Thanks in advance.

Mark

[Melbo]

Mark

I don't have an allison I have a ZF and when I asked the same question after my rebuild I was told that the operating temp should be in the 180 to 220 range but like you I find I am typically in the 160 range.

I have never worried about it being too low.

HTH

Melbo

P.S. Say Hi to Donna  ;-)

[luvrbus]

I like for one to run between 180 and 220 at the converter (most read from the converter) or 160 to 200 at the sump reading from the line is the same temp as the sump fwiw that is the Allison specs 250 is ok for intermittent operations if it doesn't drop then I would pull over for cool down.

The Allison's don't care for low operating temperature with low temps the oil loses it cleaning ability allowing build up on the clutches so I have always been told by Allison but it seems like you are ok