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700r4 Need to verify bad band

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9.1K views 4 replies 2 participants last post by  BrokenTruckGuy  
B
#1 ·
Hey there. I’ve been lurking through the site ever since my 700r4 started skipping second and going straight to third (no fourth either). It doesn’t slip in 1st or 3rd. I am pretty sure it is the 2-4 band, but wanna make sure before I remove the tranny.
I have checked and double checked the tv cable, 1-2 accumulator, and the servo; all seem good. (the guy at the tranny shop told me that if I took the pan off and stuck an air nozzle up to the little hole that goes into the servo cavity, I should be able to see the band move about 1/16th to 1/8th of and inch., and it would mean the servo was good. I did and it did.) Does this sound right? He also told me the servo looked good.

Could this be a valve body problem? It seems like I started having trouble after a fluid change. Could I have knocked a piece of crap into the fluid?

I’ve got the back tires off the ground. If I lay on my back I can turn the driveshaft in both directions with just my hands. It is a little tighter in one direction than the other, but not all that hard either way. Does this mean worn/burnt band? Can I inspect the band before I remove the tranny?

Thank you in advance for the help. And thank you for everything I’ve learned so far. It is a great site.

Mark
 
#2 ·
you can test the servo cover for travel. With engine 'off' , you should be able to push the servo in with a leverage bar or large screw driver of some type. You can use the vehicle body as a leverage point to push the cover in

The cover should only push in about 1/8 of an inch, maybe a bit more. If the cover pushes way in, you have a band problem. Worn out band and drum, mis-stabbed servo and the pin is not contacting the band strut

You can not really see much of the band with the pan and valve body removed
 
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#3 ·
"The cover should only push in about 1/8 of an inch, maybe a bit more. If the cover pushes way in, you have a band problem. Worn out band and drum, mis-stabbed servo and the pin is not contacting the band strut"
Click to expand...
That is one of the reasons I am not sure about the band. I did that (per your instructions to another memeber with similar problems) It pushed in about an eighth of an inch. Also, the fluid doesnt look that bad.

I have never checked line pressure, but i have first and third. Is it possible to have line pressure in first and none whatsoever in second (so that it won't go into second no matter how i shift or feather the gas pedal)

I read somewhere on the site (I think it was you, but cannot find it now) that if you turned the output shaft, it should turn eaqsy one way and hard the other. Do i have to take off the driveshaft to do that or can i just do it with the wheels of the ground? I can turn the driveshaft with just my hands.

Thanks again for all the help. Everything i checked before was from your instructions to other members.

Mark
 
#4 ·
BrokenTruckGuy said:
That is one of the reasons I am not sure about the band. I did that (per your instructions to another memeber with similar problems) It pushed in about an eighth of an inch. Also, the fluid doesnt look that bad.

I have never checked line pressure, but i have first and third. Is it possible to have line pressure in first and none whatsoever in second (so that it won't go into second no matter how i shift or feather the gas pedal)

I read somewhere on the site (I think it was you, but cannot find it now) that if you turned the output shaft, it should turn eaqsy one way and hard the other. Do i have to take off the driveshaft to do that or can i just do it with the wheels of the ground? I can turn the driveshaft with just my hands.

Thanks again for all the help. Everything i checked before was from your instructions to other members.

Mark
Click to expand...
With the wheels on the ground , the drive shaft should not turn by hand. When you are able to spin the trans output shaft, there will be more resistance one direction than the other.

You describe a band problem, yet you mention all the areas and parts have been checked.

What is the history on the transmission? Mileage and age if you know.

Since the fluid was changed , what was the condition of the fluid and how much debris in the pan? Did you brake open the old filter for a look - see inside the filter?
 
B
#5 ·
well, I got back under there with a pry-bar, and sure nuff, it does push in close to 3/8th of an inch (i had previously been using the back of a hammer and it was holding up on something) :embarrass

Thank you both for all the help, i never would have re-checked it otherwise.

one last question. If i drive it like it is, will i be ruining anything that isn't already ruined?
Mark
 
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