I've had my 1985 Ford E350 class C motorhome with a C6 RWD (w/ diesel engine) for over 2 years and it's always had late upshifts (2nd at about 25, 3rd at about 35-40) but has never otherwise really been a problem. When manually shifting from 1st to 2nd while below 25mph, it instantly shifts smoothly. 2nd to 3rd is also smooth, if not a bit too smooth. When shifting into D or R, there is no noticeable delay, so the clutches seem ok. It's relatively low mileage (about 75k original), just 36 years old.
It also noticeably downshifts to second when braking/idling down to a stop. It's not harsh, but it's noticeable since the engine RPMs go up some. Sometimes if I roll through a yield at about 5mph, it's still in second gear for some reason, so it doesn't always downshift to 1st like it should. More recently, it has started having a delay when taking off from complete stops, which may be a "still in second gear when stopped" issue, where it has to downshift to 1st before it takes off. No bucking or banging, just a delay when taking off from the stop. It's like there is a delay, then it grabs and takes off. it does that maybe 35-40% of the time when stop and go city driving.
I'm suspecting it may be hardened seals, which I know means "rebuild time" but it's not a good time for me. If I could put it off for 6 months, that would be very helpful. I am a full time RVer so it's my home and my "daily" driver, though I'm often parked for 1-2 weeks off grid on BLM or FS land, so it doesn't get a ton of miles on it relative tp people who commute 5 or more days a week. If gets maybe 250 miles a month, some months. Others it gets far more. It got about 1,300 miles within a few weeks last November.
I replaced the fluid last summer by dropping the pan and also draining the torque converter, so I know the fluid itself is relatively fresh. I put in conventional Valvoline Dex/Merc, a new filter, and a cheap aftermarket pan with a drain bolt, so at least replacing the pan fluid will be as easy as an engine oil change.
I'm debating if I should try half a bottle of additive such as Lucas or Bars trans fix, run it for several hundred miles, then drain the pan and replace the fluid. That's what this trans tech says he would do:
It also noticeably downshifts to second when braking/idling down to a stop. It's not harsh, but it's noticeable since the engine RPMs go up some. Sometimes if I roll through a yield at about 5mph, it's still in second gear for some reason, so it doesn't always downshift to 1st like it should. More recently, it has started having a delay when taking off from complete stops, which may be a "still in second gear when stopped" issue, where it has to downshift to 1st before it takes off. No bucking or banging, just a delay when taking off from the stop. It's like there is a delay, then it grabs and takes off. it does that maybe 35-40% of the time when stop and go city driving.
I'm suspecting it may be hardened seals, which I know means "rebuild time" but it's not a good time for me. If I could put it off for 6 months, that would be very helpful. I am a full time RVer so it's my home and my "daily" driver, though I'm often parked for 1-2 weeks off grid on BLM or FS land, so it doesn't get a ton of miles on it relative tp people who commute 5 or more days a week. If gets maybe 250 miles a month, some months. Others it gets far more. It got about 1,300 miles within a few weeks last November.
I replaced the fluid last summer by dropping the pan and also draining the torque converter, so I know the fluid itself is relatively fresh. I put in conventional Valvoline Dex/Merc, a new filter, and a cheap aftermarket pan with a drain bolt, so at least replacing the pan fluid will be as easy as an engine oil change.
I'm debating if I should try half a bottle of additive such as Lucas or Bars trans fix, run it for several hundred miles, then drain the pan and replace the fluid. That's what this trans tech says he would do: