tranni oil questions!
June 3rd, 2013, 9:24 PM
#1
CF Junior Member
Thread Starter
tranni oil questions!
hey guys, i have some questions about the tranni oil and temperature. i have 67000 miles on my 2008 suburban LE, i checked the tranni fluid and its still reddish in color. currently my tranni temp shows under normal driving 180 degrees, even when i added a external tranni cooler 2 monthgs ago. so i guess towing on my trip in juli would bring it up.
1. when is it time for a tranni oil change?
2.what fluid do you recommend?
3.does new fluid do any change in temp?
4.should the differential oil be changed too?
5. whats a bad tranni temp?(often asked question, but couldnt find a good answer...)
thanks for any help ;-)
1. when is it time for a tranni oil change?
2.what fluid do you recommend?
3.does new fluid do any change in temp?
4.should the differential oil be changed too?
5. whats a bad tranni temp?(often asked question, but couldnt find a good answer...)
thanks for any help ;-)
June 3rd, 2013, 9:35 PM
#2
Administrator
I think the owner's manual answers most of your questions. I don't believe the new fluid will affect the tranny temp.
While about 200*F is about the max tranny temp, short excursions above that shouldn't be too serious.
While about 200*F is about the max tranny temp, short excursions above that shouldn't be too serious.
June 4th, 2013, 9:13 AM
#6
Administrator
I just happen to glace at my transmission temp this morning, it was 135F with an outside temp of about 73... I too have the ext cooler...
I have heard several versions of good temps bad temps... seems like I heard that you want to avoid extended periods above 230...
I have heard several versions of good temps bad temps... seems like I heard that you want to avoid extended periods above 230...
June 4th, 2013, 10:01 AM
#7
Super Moderator
You really should try to keep the Tranny Fluid temperature between 175° and 200°. Transmissions are much like Engines, they work better and last longer, when they're within proper operating temperatures. Having the Fluid running through the Radiator Capsule, is a very efficient (& IMHO very necessary) way to get the Fluid up to temp quickly. Coolers, in hot climates, can be very helpful in reducing the effects of temperature surges by the Engine Coolant, during quick stops or slower driving with A/C Equipment operating. The Radiator Capsule and Cooler, are the ONLY way the Transmission has to control it's temperature.
Customarily, Coolers are placed after the movement of the Fluid through the Radiator Capsule, and can actually be counter productive during the winter months. or even year round in some climates, depending on the size of the Cooler. You always have the option to put a Bag over the Cooler, or partially block the Air Flow to it, to make seasonal accommodations. However, I recommend that one should have a Temperature Gauge for the Transmission Fluid, before this type management is implemented.
Follow the instructions in your Operators Manual, concerning the type of Fluid you should be using, and how often to change it.
One thing for sure, is, that you can't, from an operational/reliability point of view, change the Fluid too frequently.
PS:
I would gladly pay extra (to GM) if they were to OEM install a Thermostatic Valve, to meter/direct the Transmission Fluid through the Radiator Capsule, and/or External Cooler to control the Fluid Temperature.
Customarily, Coolers are placed after the movement of the Fluid through the Radiator Capsule, and can actually be counter productive during the winter months. or even year round in some climates, depending on the size of the Cooler. You always have the option to put a Bag over the Cooler, or partially block the Air Flow to it, to make seasonal accommodations. However, I recommend that one should have a Temperature Gauge for the Transmission Fluid, before this type management is implemented.
Follow the instructions in your Operators Manual, concerning the type of Fluid you should be using, and how often to change it.
One thing for sure, is, that you can't, from an operational/reliability point of view, change the Fluid too frequently.
PS:
I would gladly pay extra (to GM) if they were to OEM install a Thermostatic Valve, to meter/direct the Transmission Fluid through the Radiator Capsule, and/or External Cooler to control the Fluid Temperature.
Last edited by SWHouston; June 4th, 2013 at 10:53 AM.
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June 5th, 2013, 8:07 AM
#9
CF Junior Member
Thread Starter
Just talked to 3 GM dealers, and they all said that the normal operating temp is between 165-200 depending on weather. Towing I will see 200-240, if it gets over 240 for a longer period I should back off. Critical temp starts at 270.
June 5th, 2013, 10:22 AM
#10
Super Moderator
Well, that 165-200 doesn't sound too bad, but, I'd sure be doing something about it at 240 and would be compelled to do a Fluid Change if I "had" to let it run up to 270 ! 
Also, that would be putting your Engine Cooing System in hi gear. The area of that Capsule is maybe about 15% of the total area of the radiator. Even with a 16# cap, you're only bumping your boiling point up to 268°. And, you got to consider that those high temperatures are hitting the Cooling System first, THEN getting reduced by auxiliary Cooler(s).
You ought to do a search on specific brands of Fluid and get a better picture of just what others think the ranges should be. From what I've seen, those upper numbers you gave are not recommended. One does have the option to add a secondary (in series) Cooler, or change out to a larger unit, possibly even with a Fan. The way it's set up now is good up to a point, but, I've always thought that at a certain point, diverting the Fluid completely away from the Cooling System, is much better.
HA, did the guys at those GM's, know if your ride was in or out of warranty
Also, that would be putting your Engine Cooing System in hi gear. The area of that Capsule is maybe about 15% of the total area of the radiator. Even with a 16# cap, you're only bumping your boiling point up to 268°. And, you got to consider that those high temperatures are hitting the Cooling System first, THEN getting reduced by auxiliary Cooler(s).
You ought to do a search on specific brands of Fluid and get a better picture of just what others think the ranges should be. From what I've seen, those upper numbers you gave are not recommended. One does have the option to add a secondary (in series) Cooler, or change out to a larger unit, possibly even with a Fan. The way it's set up now is good up to a point, but, I've always thought that at a certain point, diverting the Fluid completely away from the Cooling System, is much better.
HA, did the guys at those GM's, know if your ride was in or out of warranty
Last edited by SWHouston; June 5th, 2013 at 11:09 AM.