How many of you add 1-2 quarts extra and why?
At the same time , how many do not add, or even change the tranny oil and why?
There is an opinion that if you haevy tow, it may be highly recommended.

 

+ 1 quart. Gets more lube to the rear bearing. That Texaco "lifetime" fluid is vague in my opinion... it says lifetime but not as to the lifetime of what! I run the Redline MTL because I don't tow a lot of weight very often. Some guys prefer the Amsoil Severe Gear 75w140 that heavy tow.

 

Changed mine a few weeks ago and what came out didn't look all that bad but since I do tow some and have been getting some griding going into 4th (if I shift it to fast) so I thought why not.

I got just about 5 quarts in it by driving the truck up on ramps on the drivers side. Used Pennzoil syncromesh.

At first the shifting didn't change but after awhile it did get better

 

I thought the over fill was done so the input shaft bearing wasn't starved for oil when towing up a steep grade?

 

I think the theory is that the rear gears do not get enough lube when towing heavy. For the cost of 1 quart of lube, sound like a no lose proposition.