Hello All,

My first Ford HD, so you guys are a Godsend. Bought 2001 F250 used so unclear on history. Bought at 110K, Trans scattered at 121K. "completely" rebuilt. Shifts fine but no engine braking. Trans shop said all OK as far as the trans goes. Maybe the chip. Took to Ford, there was a super chip of some kind, but as no controller came with truck, I had Ford restore to spec. Still no engine braking. The Ford tech mentioned a "one way clutch" which I'm guessing is a " coast clutch. I believe that when I manually drop a gear, the tach should show higher RPM and track slowly down as the truck loses speed. I gotta take it back to the Trannie shop, and it sounds like their going to have to tear it down again. Any comments, insights, advice VERY welcome!

2001 F250 Crew 4WD with 7.3 Diesel

 

you should have a coast clutch think it comes on from 40mph up,mine takes a rew seconds to come on and will stay on unless I touch the brake then will release

 

in OD the tc unlocks under 40 MPH with OD off the TC unlocks at 35 MPH.this maybe what you are feeling..it makes the truck feel like it is in nutrale..

 

No, that's not how the coast clutch works.

It's NEVER on in 4th gear, because there is always engine braking in 4th. It's very slight due to the trans ratio in 4th, so it isn't really usefull.

The coast clutch will come on in 3rd gear ONLY if the OD off light is on. If the OD light is off the coast clutch stays off in 3rd.

The coast clutch will come on in 2nd gear ONLY if the OD off light is on, or the shifter is in the 2 position. If the OD light is off and the shifter is in D the coast clutch stays off in 2nd.

The coast clutch will come on in 1st gear ONLY if the OD off light is on, or the shifter is in 1. If the OD light is off and the shifter is in D the coast clutch stays off in 1st.

Around 2001 there was a machining problem with the coast clutch drum. The groove for the snap ring that holds the clutch together wasn't machined deep enough and the snap ring would often come out of the groove. When that happens the coast clutch no longer works. Usually, but not every time, it won't break other parts, but sometimes it does.

 

that is how it works,definatly in fourth gear

 

If your coast clutch is on in 4th gear the trans will be locked up. All three elements of the overdrive gearset will be held to the case, so the input and output shafts will stop turning. That means the wheels are going to stop turning, too. Your coast clutch IS NOT on in 4th gear. It can't happen.

You will have engine braking in 4th gear because the overdrive clutch is on and provides engine braking in 4th gear instead of the coast clutch, which CANNOT be on in 4th.

I think you are mistaking the torque converter clutch for the coast clutch.

 

all I know if I am much over 40 mph no matter 45 or 100 when I let completely off the throttle it's like it down shifts to a lower gear and the rpms come up a little
if I touchthe brake it goes to a normal coast,when I let off brake it does the same again
if I lock it in third there is never sny change with throttle on or off

 

I'm tired of answering both of these cross posts. The rest of the conversation is here:

https://www.ford-trucks.com/forums/6...ml#post5313452

 

Your coast clutch probably wasn't assembled correctly. There's several snap rings involved. Check this thread for details... https://www.ford-trucks.com/forums/628367-using-engine-to-slow-down-when-towing-not-an-exhaust-brake-question-3.html Posts # 39 and #40 give pics from the Ford tranny shop manual, and it clearly states that engine braking in 1st and 2nd manual occurs with the coast clutch engaged but the TC clutch disengaged, so your lack of engine braking has nothing to do with the TC clutch. Post # 51 gives a link to pics of the coast clutch being assembled into the tranny.

This thread gives some additional info on engine braking with a diesel... https://www.ford-trucks.com/forums/629052-torque-converters-and-diesel-engine-breaking.html