Tranny Question
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Freshman User
Joined: Apr 2002
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Tranny Question
I have a 75 f-150 with a 360(soon to be 390) and a rebuilt automatic C-6 tranny. When I first crank up the truck and put it in gear, it takes several seconds for the tranny to engage. I am not sure if the torque converter was replaced or not. Would the torque converter cause this or is there something else causing this? I am new to this and I was wondering what the torque converter does and how it works. Thanks for any help and advice ya'll can give. 
Elder User
Joined: Jan 2002
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Tranny Question
How long ago was it rebuilt? (miles) It is not likely that the torque converter is causing the problem. The reason it is slow to engage is because the fluid pressure is not coming up right away. That could happen because the fluid level is low. Could be a problem with the "front" pump being worn excessively. (not likely) Could be a sticky valve in the valve body (very likely). Could be dirty fluid and a clogged filter. (Not likely on a recent rebuild) Could be a seal somewhere inside allowing fluid to leak past. (Not likely on a recent rebuild, very likely on an "old" rebuild.)
Check the fluid level, the condition of the fluid and filter and repost for further analysis.
Check the fluid level, the condition of the fluid and filter and repost for further analysis.
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,731
Likes: 2,658
From: SE Florida
Tranny Question
Next time the truck has sat without running for several hours check the transmission fluid before starting the engine. If it is quite a bit overfilled you have a leaking or stuck converter drainback valve.
If this valve doesn't work right the torque converter will drain into the pan, causing the overfill. When the engine is running it will take several seconds to get enough oil into the torque converter for it to operate.
Mark
If this valve doesn't work right the torque converter will drain into the pan, causing the overfill. When the engine is running it will take several seconds to get enough oil into the torque converter for it to operate.
Mark
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Tranny Question
Thanks for the help guys. It's a long story. I'll make it short. I owned the truck for a year or so. My brother bought it from me a year and a half ago or so. I just bought it back. He had to have the tranny rebuilt because it went out on him. I'm not sure what all was done to it, but, he supposedly says everything in it was replaced??? It was rebuilt no more than a year ago and may have been driven no more that 12,000 miles or so. I let the truck sit overnight. The next morning, the tranny dip stick showed fluid about 3 inches over the fill line. Also, I noticed a few drops of tranny fluid on the ground. 
I am going to have to get with my brother and see who repaired this thing. 
Once the tranny engages, it shifts very positively and runs smooth. Also, another question if I may. What exactly does stall speed refer to when talking about torque converters. I have always heard this talked about but do not have a clue what this means. Thanks for the help again. You guys have helped me tremendously! 
I am going to have to get with my brother and see who repaired this thing. Once the tranny engages, it shifts very positively and runs smooth. Also, another question if I may. What exactly does stall speed refer to when talking about torque converters. I have always heard this talked about but do not have a clue what this means. Thanks for the help again. You guys have helped me tremendously!
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,731
Likes: 2,658
From: SE Florida
Tranny Question
You need to fix or replace the torque converter drain back valve. It's leaking or stuck. It's in the valve body.
Stall speed is the maximum RPM slip the torque converter will allow. If you hold the brake and floor the accelerator the engine speed that you get is the stall speed of the torque converter in that truck.
Mark
Stall speed is the maximum RPM slip the torque converter will allow. If you hold the brake and floor the accelerator the engine speed that you get is the stall speed of the torque converter in that truck.
Mark
