Truck won't hold 2nd gear when towing

[mick883]

Just got a 99 crew cab f 250 7.3 and I noticed when am towing, the truck won't hold 2nd gear.
When I pull out (even on a hill), 1st gear winds out nicely with turbo and then it shifts into 2nd gear for about 1 second and then quickly shifts into 3rd gear. When that happens, i loose my turbo and the truck is now lugging with very low RPMs until the turbo eventually kicks in and then I am fine. i am towing with the overdrive off (not like it matters in 2nd gear).

I have heard 2 things told to me. one guys said yes, it is a tranny problem and that it is slipping out of 2nd when it has a load on it (it seems fine if I pull out normal with no load). Another person said it sounded like i have a turbo problem. Can anybody give me their input into the matter.

I would like to go to the shop and have a pretty good idea about what may be wrong. Thanks.

[mick883]

Anybody? I heard this was a good place for advice!!

[Deeno]

Originally Posted by mick883

Just got a 99 crew cab f 250 7.3 and I noticed when am towing, the truck won't hold 2nd gear.
When I pull out (even on a hill), 1st gear winds out nicely with turbo and then it shifts into 2nd gear for about 1 second and then quickly shifts into 3rd gear. When that happens, i loose my turbo and the truck is now lugging with very low RPMs until the turbo eventually kicks in and then I am fine. i am towing with the overdrive off (not like it matters in 2nd gear).

I have heard 2 things told to me. one guys said yes, it is a tranny problem and that it is slipping out of 2nd when it has a load on it (it seems fine if I pull out normal with no load). Another person said it sounded like i have a turbo problem. Can anybody give me their input into the matter.

I would like to go to the shop and have a pretty good idea about what may be wrong. Thanks.

Is your ses light on? Seems kind of weird that it only does it when towing. Maybe try shifting manually and see what it does. Have you checked the tranny fluid? Maybe time for a fluid and filter change?

[Greg.cg]

We have two codes on a 99 f350 the codes are P1670 and P1316 we had the truck in last week and it would keep dying we replaced the cps ran good a few days and now back again is there any test for these codes i do not want to replace the IDM if that is not it like if it were in the harness any help would be nice thanks

[sawyer1]

Are you sure its not the toque converter locking?