Have a 2001 f350 that runs great until you hook a trailer to it. Once a trailer is hooked to it and you are on a slight incline (and I mean slight) it will not go into D.. It's like it gets stuck in N.. Have to jam it into 1 to get it to go.. Once level again it will go back to D... Any insight would be appreciated. Truck has 177k miles on it.

 

Does the shifter feel weird or does it go in to all the positions as normal?

when you take off in 1st does it rev like crazy or just accelerate normally?

 

Ever service the transmission any?

So the shifter won't even go to the D position?

 

Before you drop the nose onto the hitch, with the truck in position, lock the emergency brake and hook up. Does it go into drive before you release the brake? If not, unplug the umbilical and try again...

 

Is the trans fluid low?

 

Tans fluid is fine. Haven't done work to the tranny yet. Considered putting a new tranny in. It will go to D but when I push on the gas it just revs up like it's in neutral. Put it in 1 and it's slow to go but will go. I have not tried the brake trick.

 

Ok...so the trans is slipping with a load.

but no load and in Drive it does ok?

 

Yes but it doesn't do it all the time.

 

Do you have 2wd or 4wd? if 4wd, does this happen in 4wd?

If you have 4wD, and it does not happen in 4wd, but does in 2wd, you have a rear deffierential problem.

if this happends no matter if in 2wd or 4wd, and you have an automatic, certaily its a tranny or tranny subsystem. time for an expert.

how many miles on tranny, miles since last service, chance of clogged filters?

the malfunction if on an incline or not, certainly sounds like low tranny fluid to me...are you checking it while someone has it in gear with their foot on the brakes...I don't think checking tranny fluid in neutral is reliable.

I had a vehicle once doing simular misbehaviors and the problem was clogged tranny filter...but the tranny needed a rebuild becuase the filter was clogged with tranny plate parts....little rubber peieces that looked like charcoal.

 

Trans fluid should be checked with the engine idling in park or neutral. Checking in drive will not necessarily give accurate results.

The only way that an internal filter will clog is when the trans fails.

 

It is a 4 wheel drive I have not tried it in 4 wheel I've only tried it in 2 wheel. I don't know if my husband has tried it in 4 wheel. It has 177k miles on it and we are not the first owners. I am not sure what all has been done.

 

Time for an expert diagnosis of the tranny. Time for a rebuild I believe.

But service the thing first. As Mark suggested. Check the fluid properly.

 

I will check the fluid and go from there. Thanks so much for all your help.

 

there is a plastic module on the transmission called something like the park drive reverse sensor, it is on the drivers side of the transmission and when mine was going out, it would not shift out of first gear until i dropped into second and then upshifted back into drive. occassionally would not go into drive unless i put pressure on the drive position.
check out the module.

 

Thanks! I'll check it!