OK like to start off saying this is a great site. My truck is a 1999 4.0 4x4 auto with 133000 miles. My problem is that when the truck is under a load (going up hills or pulling a trailer) when it downshifts from over drive to fourth the drive train vibrates really bad. I have noticed it before but yesterday I was helping my brother in law move while pulling a trailer I noticed it really bad and it started to have a longer vibration. I have seached and found that some have had similar problems but none sound just like mine. I think that my tranny my be on the outs but was hoping that someone would be able to help. Also I am unsure of the tranny fluid being changed before i owned the truck and have heard that with that many miles it my be a bad idea. Thank you for any help.

 

anybody?

 

perhaps a bad carrier bearing?

 

I have a tranny problem liek that but its w/o towing lol gotta love the 5R55E

 

maybe ill have to research that a little bit. i am really worried that it just needs a rebuild.

 

shouldn't really be using overdrive towing heavy loads. oil gets way too hot. as far as changing the tranny oil, miles shouldn't matter. i would not recommend a complete tranny flush with high mileage but new oil and filter should be fine.

 

take OD of when u tow,, cmon this is comen sense my freind,,, 4.0 should b able to handle it but i would try towing a load with od off and if it runs good then good, as for uphils,, no idea. rebuild not worth it 133 is alot, i just bought and installed new tranny on my truck, 99 3.0 4x4, $450 for a used tranny and T-conv, 65kmiles on it,,

 

I do take over drive off when I am towing. but thanks. As far as going up hills?


While pulling the trailer it was when the truck was going to fourth gear. I noticed after pulling the trailer that it seemed to be worse. I have noticed it before while coming home from work. It seems like its the worst when the truck gets warmed up. On down shift from over drive to fourth. Thanks again for the help. I also was going to changed the tranny fluid today and didn't because the fluid is very brown and burnt smelling. I know that is not a very good sign.