Was under my new DD rig today, and i noticed there a few little dents here and there on the transmission lines, the steel part. There are a few in each line. Is this something to be majorly concerned about or is it ok to leave it be? I will have a photo up tomorrow afternoon. Thanks in advance

 

As long as they aren't major dents that would obstruct flow of fluid through the line i would think it is nothing to worry about.

 

Obviously I didn't get the picture today, but how do I really tell if its enough to cut off enough flow. I mean none of the dents are all the way pinching the line, but there are some small ones and a few larger ones. Is there anyway to know if its bad enough to cause a problem? I also had another question, I was flippin through the chiltons manual, and it said in the book the trans takes Dex fluid. I put ATF+4 in it when I topped off (dipstick says ATF type 7176 which is +4). If the previous owner used Dex and I added ATF4 will it lead to any problems down the road? Im gonna drop the pan this weekend but there is still a possibility that there could be Dex in the system cause m not flushing it. Will the mix of two fluids be a problem?

 

don't use anything except ATF+4 in your trans. if think 7176 was ATF+3 which was superseded by 4. Dex-3 is absolutely wrong, but there's not too much you can do about it except dump the old fluid by disconnecting the pressure line at the cooler and letting the pump dump it. consider this and do one-two quarts at a time. don't let anything run dry.

a blend of Dex and ATF won't do anything terrible, except that it still has the wrong properties and the more ATF and the less Dex the better.

i'd say if the cooler line is dented half way or less, its ok. if more than half, i'd think about either replacing the whole line, or replace a section with new line and compression fittings. it should be 3/8 inch steel line. its not real high pressure line like a brake line, so a compression fitting, or even a section of trans hose with double clamps is ok.

 

Im pretty sure the worst dent out of all is close to half way but not more than half. I guess ill leave it be for now, got more important things to spend on with this truck haha. Havent had any problems from the trans so I guess if its not broke dont fix it right

 

Dented half way reduces flow by more than 50%. Has to do with cross sectional area. Not broke? Better add the word "yet" to it then. Reduced flow equals higher tranny temp, and heat is the enemy of transmissions. Waiting until something is broken is not sensible. Relpace the line - it should not be that expensive. A rebuild on the other hand - is NOT cheap. Rebuild is $1200 minimum, plus the time the truck is down. Guess one has to determine what is important.

 

As a junior Mechanical Engineering student currently taking a fluid mechanics course i would concur with the above.

Required pumping power increases by a power of 4 with diameter to maintain flow. Half the diameter means 16 times the pumping power needed. Obviously this isn't exact for your situation, but it is still a major problem. Your pump is working overtime, pressure is increased and temperature is increased. High temps kills transmissions.

A small dent is no big deal, but if it's bent to the halfway mark that's a very significant kink in the line. Personally i'd replace the line. Pretty easy fix for something that could cause major failure. These transmissions aren't known for their strength in the first place.

 

I am going to replace the lines very soon...main point of the question was to see if it was OK for now, the fins on the trans cooler are also pretty damaged...is that another big issue?

 

i might change the pan gasket tomorrow so while im under the truck ill take a photo and let u guys take a look...sub to the thread should have them up by noon or one tmorrow

 

darn kids. always trying to insert facts into opinion.