Trans Started slipping on freeway-Dead on Streets

2003 4.2 4x4
oil changed ever 5-7k
trans fluid changed ever 25k, most recent was at 120k

So, wife and I were heading back from visiting family, and after coasting down hill on freeway, I noticed a lack of power on flat level ground @55mph. Noticed we were sitting at 3.5k rpm at that speed, and on level ground (ie, not accelerating/little load).
Dropped into "n" and back to drive again, same thing.

*Prior to this was all freeway driving 55-70, no large inclines or anything like that.

Exited freeway, hit red light of course. On green, trans made grinding noise and was clearly slipping/having issues, pulled over as soon as possible.

Checked oil/trans fluids-all good (well, fluid there lol).

Drove another 1/2 mile to safest area, by the time we got there it would just rev up in drive/not go.

Called aaa, and while waiting, tried driving again in parking lot only. It seemed when it was cooler (sat for 15+ minutes) it would drive, but didn't continue testing (only drove a few circles in parking lot).

AAA arrived, towed us home.

Any ideas on what it could be? Weighing what to do now...


Well-Known Member
hmm, so I went for a quick test drive-everything acted normal. Granted, I only drove the neighborhood and used reverse, 1st, and 2nd.
Even if you can drive it a little, you most likely have transmission work in your near future. Depending on where I looked and what I was willing to do myself, I have estimates between $1000 (for me to do mostly myself, slowly) and $3500 to drop it at a transmission shop and let them have at it.


Lifetime VIP Supporter
From your description, I would say sunshell as well. Since you can drive again once it sits, I'll guess the shell either fractured, or you lost some splines / lugs off the end.

Try not to drive it until you can get it looked at, rebuilt, or replaced. As it heats up, the metal expands...and you can probably guess the rest.

Trans has to come out to replace the sunshell. Since it does, decide how you want to address it. A builder can make it near bulletproof, but that costs the most (best option if keeping the truck).
A used one from a junkyard, craigslist, etc. will be cheapest, but you won't have any recourse if it fails. You also have to deal w/ removal / reinstall.
A new rebuild is somewhere in between, plus you'll have a core charge where you'll have to return at least an intact case assembly. Same R&R applies; some vendors will supply names of local installers (and any warranty issues are easier if you use them; a lot more difficult or non-existent if you don't)
okay, update.

I drove around the neighborhood again, everything acts normal. However, after about 1/2 mile, it started to slip again. No weird grinds/crunches etc...just starts acting like it's in neutral.

Any ideas?
Slippage is not a good sign. If the fluid is in good condition and proper level, it probably needs internal work. Maybe pump pressure is low, which would explain that it works when cold and loses pressure when warm.


Lifetime VIP Supporter
Agreed. About the only thing you can do to narrow it down further is to try shifting manually to see if you can get through all four gears when warm. But that trans has to come out, so get ready.

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