Down shift engine braking
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New User
Joined: Apr 2005
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Down shift engine braking
I have a 2001 f-350 4x4 with 90,000 miles. When pulling a trailer I would tend to push the OD button to have the truck engine brake in third gear when going down hills. Last time I used the truck pushing the button actually allowed the truck to coast. It does shift down to third it is just that the torque converter seems to disengage. Any ideas on why the engine braking quit? All other aspects of the transmission seem completely normal.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com
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Thanks in advance.
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Elder User
Joined: Mar 2004
Posts: 509
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From: Pasco, WA
Did the engine go to idle? Move the gear selector up & down while keeping it in 3rd gear and coasting. If the engine goes to idle, check the alignment of the park/neutral safety switch on the transmission.
Posting Guru
Joined: Jul 2003
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If it goes to idle when you turn off overdrive and when you move the shifter to 2 or 1, the coast clutch isn't working. It isn't the torqe converter, you will get engine braking with the converter clutch locked or not, as long as the coast clutch is working, too.
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Thanks for the replies. It does go to near idle when I push the OD switch to 3<SUP>rd</SUP>. at @55mph. In overdrive at 60 it does not move to idel when I let off the gas. At 45mph When I move the shifter to second it dose engine brake. I assume that means the coast clutch is working? I will have to look into the park/neutral switch and wiggle the shifter around when trying the 3<SUP>rd</SUP> gear braking. Last time I used the truck was to haul my tractor down a logging road so the switch may have gotten misaligned because it was rather rough. Where is the switch located?<O</O
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Posting Guru
Joined: Jul 2003
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The TRS (what you are calling the neutral switch) is not the problem. Since you have engine braking in 2nd, the problem is either a bad coast clutch soleniod, or the wiring to the solenoid. Since there is engine braking in 2nd the coast clutch is fine. It is not actuated by the solenoid when you move the shifter to 2, so that narrows down the search to what I mentioned above.
Elder User
Joined: Mar 2004
Posts: 509
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From: Pasco, WA
I have to disagree that the switch is NOT the problem since that is exactly the thing I had to adjust to fix the same symptom. That switch is more than the park/neutral safety switch; it contains a resistor ladder that indicates every possible gear position.
