I installed a tranny gauge a while ago and it runs around 150° or about normally. When I pull something, when is hot too hot?? 200°, 250°?? Just wondering what temp to look for trouble.

 

You don't say whether your sender is installed in the pan or in the fluid output line. It makes a difference in the reading. If the sender is installed in the fluid output line, you are reading the temperture of fluid that has just been working to move your truck.

If the sender is in the pan, you are reading the temperture of fluid that has gone through the cooler unit and then mixed with other fluid waiting to be used again to move your truck.

The sender in the output line will give you the most accurate picture of what is happening inside the transmission. According to this site:

http://autos.yahoo.com/maintain/repa...ques123_0.html

175 degrees is the highest you should be running the fluid in order to get maximum life from the fluid. For every 20 degrees over 175 degrees you cut the effective life of the fluid in half. I read on another site that at 320 degrees brand new fluid will have a twenty minute life span.

The damage to the fluid is actually done to the fluid's ability to lubricate the parts in the transmission. Heat destroys the fluid's ability to lubricate and when that lubrication ability drops too low, friction in the parts cause them to wear excessively.

A bad transmission is usually a delayed reaction. Bad driving habits gradually build up and then one day when you are driving empty and you try to accelerate to merge with traffic or something you notice a slow shift or some slipping. The damage may well have been done last summer when you pulled that two mile hill with the travel trailer on the back at 65 MPH just because you had the power in the engine to do it. The rest of the time the fluid was slowly grinding the clutches away.

A tranny temperture guage is essential. Put it on the output line and watch it any time you are towing. You will learn to stay off the throttle and downshift long before the transmission does it for you.

 

the link did not work.

 

Hmmm. Let's see if this one works:

http://autos.yahoo.com/maintain/repa...H2OiUkgqKDc78F

It looks like Yahoo changed the address of it. I will check it as soon as it posts to see what happens. Thanks for the heads up.

 

Phooey! It looks like Yahoo is keeping the link from being directly accessed. One more try and I'll give up. Try is link:

http://autos.yahoo.com/maintain/repairqa/

Then click on 'transmission' and then click on the first question under 'automatic transmission'.

 

Now it is the forum software. Cut and paste that last address into your browser and follow the links.

I give up. When I get a chance I'll look up a real site that has the same information. Sorry about the inconvenience.

 

Thanks for the info, I figured I would ask because what is the sense in a gauge if you don't know when to stop?? I have it in the pan as that is where the directions said. I get what your saying though. Thanks!!

 

Check out this link. Hope it works.
http://www.transmissioncenter.net/TransTemp.htm

 

That kind of sums it up, thanks!!

 

That chart is useful if you're running 1960's Type F fluid, but things are nowhere near that bad if you have MERCON or MERCON V fluids. These fluids can take A LOT more heat than the old fluid.

That chart is also useful if you're selling transmission coolers.

Ford's specs for maximum trans pan temps is 220°F continuous, and 250° for less than 30 minutes.

 

Ford specs are nice for selling trucks and replacing transmissions.

The newer style oil can take a little more heat without depleting the additives. The trannys will wearout prematurely with those temps!