Weird 3rd gear
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Laughing Gas
Joined: Mar 2016
Posts: 757
Likes: 43
From: Cheyenne, Wy
Weird 3rd gear
79 Bronco 351 w/C6
Today is Sat. 11-11-17. Problem started Tuesday 11-7-17 on my way to work. From first system to now, I have driven about 27 miles. Yesterday I checked fluid level and it was a quart low. Now for some reason when it gets cold here I lose tranny fluid but it does not leak out. How do I know it does not leak out? For the past 6-7 months been parking on new cement and no oil stains on the cement. Topped up the trans oil. Still the same problem. Now onto the problem.
Problem.... When in "2wd", it shifts from first to second like it should. Going from 2nd to drive, usually will not up shift and if it does, it will not stay in drive. Same wheather in "D" or manually move level.
NOW FOR THE KICKER.
When in "4LOW" the trans will up shift from 1 to 2 & 2 to drive just like it should. Both in "D" and manually. Move back to 2 high, 1-2 ok but no 2-3. Move back to 4 low and hubs unlocked, I get all 3 gears. Any ideas.
Thanks for a great site and for any insite to this issue.
Today is Sat. 11-11-17. Problem started Tuesday 11-7-17 on my way to work. From first system to now, I have driven about 27 miles. Yesterday I checked fluid level and it was a quart low. Now for some reason when it gets cold here I lose tranny fluid but it does not leak out. How do I know it does not leak out? For the past 6-7 months been parking on new cement and no oil stains on the cement. Topped up the trans oil. Still the same problem. Now onto the problem.
Problem.... When in "2wd", it shifts from first to second like it should. Going from 2nd to drive, usually will not up shift and if it does, it will not stay in drive. Same wheather in "D" or manually move level.
NOW FOR THE KICKER.
When in "4LOW" the trans will up shift from 1 to 2 & 2 to drive just like it should. Both in "D" and manually. Move back to 2 high, 1-2 ok but no 2-3. Move back to 4 low and hubs unlocked, I get all 3 gears. Any ideas.
Thanks for a great site and for any insite to this issue.
Senior User
Joined: May 2016
Posts: 477
Likes: 3
First, I wanna make sure you're checking the transmission fluid properly. Make sure the engine and transmission are nice and warmed up (drive for 20 min, especially if it's cold outside). Then idle the engine in Park and check the dipstick.
Next, there's not too many places transmission fluid can go. There's lines to the radiator, a line to the vacuum through the vacuum modulator, and lastly the ground. If you check your water and there's no funny color, and since you're experiencing problems with upshift, you should check the vacuum modulator. When it gets old, the diaphragm inside the vacuum modulator can crack and trans fluid could get sucked up into the vacuum tube. This would cause problems with upshifts and also cause some fluid to disappear over time.
Next, there's not too many places transmission fluid can go. There's lines to the radiator, a line to the vacuum through the vacuum modulator, and lastly the ground. If you check your water and there's no funny color, and since you're experiencing problems with upshift, you should check the vacuum modulator. When it gets old, the diaphragm inside the vacuum modulator can crack and trans fluid could get sucked up into the vacuum tube. This would cause problems with upshifts and also cause some fluid to disappear over time.
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