EricL

Some other tranny Q&A I’ve dug up (sorry no Honda info, but, here goes)


See the links to the oil and tranny coolers and especially to the oil and/or oil or ATF thermostat link…

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To: gmcmotorhome@mailinglists.org
From: tom warner <warner@borg.com>
Subject: Re: GMC: Tranny cooler

A tranny can incur damage if driven any distance at all running at 100 degrees. The tolerances are designed to run in its optimum temperature range of 160-200 degrees farenheit for optimum longevity.Under 160 degrees and over 200 degrees wear is accelerated.

I have seen two separate posts that say essentially: 1. the tranny needs the radiator to heat the tranny fluid in cold weather. Not true since in reality in cold weather very little fluid circulates thru the radiator from the engine block, the engine thermostat keeps the engine coolant circulating thru the engine block and the only heat the tranny gets is from the fluid circulating from the tranny thru the radiators own tranny cooler. In this case the radiator actually acts as a heat sync and attempts to cool down the tranny even more. 2. The thermostat is unreliable and can cause a problem of overheating the tranny. I dont believe this is true either. A tranny thermostat is no more unreliable than one in the engine.

I believe the ideal situation is for a separate thermostatically controlled, fan cooled, oil cooler for the tranny, thus decoupling the engine heat from interfering with the tranny cooling. The benefits are faster warm up to 160 degrees since the fluid ciruculates out of the tranny and directly back to the tranny pan without cooling until it reaches 180 degrees at which time it is redirected thru the tranny cooler. An additional benefit is the decreased resistance of the lines by eliminating the radiator cooler thus increasing the flow of coolant thru the tranny.
I am thinking of even installing larger cooler lines in/out of the tranny to the cooler for additional coolant flow and better cooling.

tom



To: gmcmotorhome@mailinglists.org
From: tom warner <warner@borg.com>
Subject: Re: GMC: Tranny cooler

Manny this high temperature may be attibuted to the torque converters that come as standard equipment. To much slipping when pulling long grades. This is where I believe the switch pitch tranny with a lower stall speed torque converter and a large parallel thermostatically controlled tranny cooler will shine. When pulling long grades you are fighting two things, more fuel burned by the engine which translates to more heat to be removed by the radiator(and passed on to the tranny) and more heat generated by the tranny caused by slipping of the torque converter if the stall speed is not exceeded. Its a vicious cycle. In addition to many people do not gear down and keep the engine RPMs up, to let the tranny oil further cool it.

I am now thinking seriously of adding:

1. An auxiliary transmission filter Permacool 10678 (http://perma-cool.com/Catalog/Cat_page25.html) , $28.99

2. Permacool Maxi-cool six pass oil/tranny cooler model 13311:
( http://perma-cool.com/Catalog/Cat_page13.html ) $149.99.

3. Permacool remote oil thermostat model 1060 (http://perma-cool.com/Catalog/Cat_page14.html) $38.99

I believe this setup will eliminate for the most part any tranny problems we now experience and keep the tranny temp close to the ideal 160-200 degrees F.

Tom

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Here is the link of interest: Permacool remote oil thermostat model 1060: http://perma-cool.com/Catalog/Cat_page14.html) $38.99


EXCERPT from the thermostat link:

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*
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* Prevents over-cooling in cold climates
* For use with transmission coolers and engine coolers

Maintaining proper oil temperature is critical in today's sophisticated engines and automatic transmissions

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