I have an F350 Turbo Deisel with 102 K miles.

I hope that someone out there can give me an idea of where I could look or do to help my issues of hard shifting when hot from 1st to 2nd and what now appears to be a heating issue again.

I purchased this truck used and it has a chip in it (maker unknown). It has a gauge on the dash that shows boost on the left and EST on the right (I was told that this represented tranny temp). the truck ran great for 25K, with the temp rarely going past half on the EST, but climbing up there on long pulls going up the mtns, then going back down when I would back off or head down hill.

I was experiencing a hard shifting from 1st to 2nd when I towed a car on a trailer last year. I had to take the truck in for emissions and there they advised that the ATF looked scorched and suggested a Power FLush.

I replaced what fluid I could get at the pan level with AMSOIL ATF synthetic and the filter. I replaced that small cooler (3"X7") in front of the radiator with larger one (9"X12") cooler to augment the standard radiator lower cooler (routes ATF from the lower portion of the radiator, to the external cooler and back to the tranny). The new external cooler has fine passage ways with fins, as those in an engine cooler, rather than the large tube with fins coming off it.

The tranny shifted great for about 1,000 miles (going over the Rky Mtns in early spring). Then this past day on the highway the temp was going up on the gauge again. I backed off and it dropped down some. At a light it again was hard shifting from 1<SUP>st</SUP> to 2<SUP>nd</SUP> – ( not shifting unless I backed off on the pedal and then allowed it to shift). Took off with it again today. It shifted fine, but after about a mile I saw the EST climbing again (it had not in the past climbed this early). EST will go up and down based directly on if I accelerate or let off. Did not drive it much today so the shifting did not come into issue.

I have to head over the Mtns again on Wednesday and tow back a trailer. I have been given some suggestions by friends and a couple thought of myself, but was hoping that someone might be able to shed some light on this issue and help me out.

The options I am considering now are:

1. Power flush the ATF, as I was told that my pan drain did not do what was needed and the old ATF would heat up faster and get me right back into the old issue I had.
2. Don’t Power Flush as I was told it would do more harm than good, and that the old fluid is fine – just change the after market cooler as the fine passage ways are probably not flowing enough and might be getting blocked from junk I did not get out earlier.
3. Replaced what fluid I can get at the pan level with AMSOIL ATF synthetic and the filter.

d. Both a and b above.

 

Hello VargasB, welcome to Ford Truck Enthusiasts.

Are you sure the other half of your gauge doesn't say EGT as opposed to EST? EGT's are your exhaust gas temperatures and most definitely respond to throttle inputs. It should have a temperature range on the gauge of betweem a low of 200 or so up to around 1600 degrees F.

It does sound like the tranny has problems. I would try the power flush and refill with synthetic.