Did stall test and then "pop"

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david30101

New member
I have a 1210 Travelall 4x4 with a 727 that I swapped in 4 yrs ago im guessing from a 74 full sized. A couple days ago I noticed after driving that it seemed sluggish from a stop and seems to slip at 1st and sec gear. I had a few pointers from the bb site that one of the tests I do do a "stall" test to determine if its the valve body or internals. After driving around in fresh snow for bout a hour so so I did the stall test. I gradually raised rpm till it got to about 2300 (not flooring accel) while holding brake. After about 4-5 seconds I felt a light pop then I stopped. The truck moved forward alot easyer then before but would not go in reverse. Felt like the brakes were applyed and the engine lugging when trying to move. At same time the tranny temp gauge was climbing very fast. Then I decided to just turn the truck off. Fluid was clean/ changed including the tc 4 yrs ago. Had approx 8k on it. The tranny was in exalant shape up untill now.
Im sure the low/rev band probably was the cause of the problem. But now the reverse servo is included. Can I replace the servo without pulling the whole tranny out? I have a longer post on this topic on the bb site in the tech forum that explains it better under the name "727 slips in first and second gear"
thanks,
david
 
Chances are better than 90% that the low/reverse servo has gone. That means it's time to pull the trans out, take it down, and refresh everything.

Make certain you keep all parts in order as they come out.

When you finally get the low/reverse band out, you will see that it's fried.
 
Ok..right now its out in garauge in 30 deg weather with snow. Im going to wait till it warms up some then ill pull pan first to see what damage has been done.
 
I was able to tighten the rear band up which took all slack out of the servo arm. I had about 1/2-3/4 inch travel in arm before made contact. Took about 6 turns of screw to remove slack. I tightend up more with a small 5/16 wrench to make sure the band would go tight without anything else comming loose. I then loosened back up to just to remove play in linkage. I dont own a inch torque wrench. Im going to remove the valve body and do a air pressure check of servo to make sure it moves properly. These are a couple pics I took after removing pan. Fluid was dark and not burnt. No broken parts. Had some medal shavings, no clutch material.
 

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What I see in the pan is tons of metal along with fiber material.

With the 5/16" wrench, tighten the band screw as tight as you can get it with one hand. Then back it of 2.5 turns.

Then do the same with the front band screw that is on the outside of the case and back it off 2.0 turns.

Should then hold about 4 quarts (maybe 5) of new oil. Try it and see.
 
That fiber material you see is just fluid left in pan. It was mostly medal shavings. Anyhow..I saw in one of your topics about the part throttle downshift module on valve body. I know mine didnt have that on it. Is there any way I can set mine up to do that? Cant that module peice be added? Im going to do the tf-2 kit. Im more conserned about shifting and converter being able to get pumped up while in park.
 
Adding the "part throttle" downshift unit won't resolve anything! Just shift with the lever when you want to engage 2d and shift back up when you need to.

Adding a tf-2 kit is always a good idea if the rest of the transmission is in decent shape. Not so if the bands are marginal (which also means the drums are marginal also).

For the best of transmissions, do it before the trans takes a total dump, and replace everything that is going to fail at some point.
 
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