low miles tranny, p0770, fault identification

01-16-2013, 10:16 AM
Good day. I own an '02 Toyota Tacoma v6 3.4L 4-speed automatic. After a 2-hour highway drive (not too common, small town) the other day, I started to experience transmission issues (wouldn't always switch gears properly), and the check engine light came on. My scanner indicated P0770 (Shift Solenoid E Malfunction), a transmission fault.

I've spoken with my mechanic, and I've done some research online. My understanding is that it could be a shift solenoid, the valve body, the torque converter clutch, or even just low transmission fluid.

I have owned this truck since '05/28k miles. It now has 95k miles. At about 35k, the dealership installed a new transmission (maybe the former owner was a city-driver, or something), and I had basic dealer transmission service about 30k miles ago. I have an appointment to take it to a local shop (a Ford authorized service center, that also services other makes/models) in a few days.

Except for infrequent highway driving, I don't drive the vehicle "hard" at all. I have the vehicle fully serviced by the dealer at recommended intervals. I have been advised that if this fix requires more than basic transmission service, that I should take it to the dealership (factory tools, etc).

These are some observations about the malfunction:

1) The engine/transmission is still cold (just started the engine). I shift from P to R, to back out of my driveway. The transmission seems to be "stuck" in neutral/park. 5-10 seconds pass, finally transmission engages R gear. Switching from R to D, vehicle operates normally.

2) While driving normally, I accelerate steadily from 20-40mph. The transmission hesitates before switching from 2nd-3rd gear (peaking at 3k rpm, holding steady). When I take my foot off the accelerator slightly, then re-apply it, the vehicle shifts. (EDIT: Subsequent to this same post on another forum, I have been told that first gen Tacomas often have a cold tranny 2nd to 3rd shift hesitation, and I have seen it before, but it's arguably more noticeable since this recent problem developed.)

Question: Does anyone see a most-likely scenario in my case? The transmission has only 60k relatively "easy" miles on it. Should I waste my money on a basic transmission service at the local shop, or should I park it, and wait until it can be brought to the dealership, incase it needs more extensive repairs?

Any advice is appreciated. :runaround:

Alternate thread: http://www.automotiveforums.com/vbulletin/showthread.php?t=723867

01-16-2013, 09:43 PM
I'd try and find a reputable independant trans shop (not AAMCO, Cottman, etc) and see what they say. Dealers aren't much on trans work, if it's under warranty and they honor it, they just swap in a new one. Otherwise most send it out to an indy shop for a rebuild. Dealers just aren't set up to do trans work, it's too involved.

Replacing a solenoid is fairly easy, you don't have to pull the trans to do it, you just need to drop the pan to get to the valve body.

01-21-2013, 09:49 PM
I know this will sound odd, but if you have a battery going out it can cause the problems you described. Also low fluid level or the solenoid and the other things you mentioned can also. I would check in that order. I cant remember the resistance of the solenoids right now, but that is how I chedk them electricaly. I fixed one awhile back by changing a battery that seemed fine until it was load tested.

02-04-2013, 01:28 AM
A bad/weak battery can cause all kinds of problems with the ECMs used in various systems in today's vehicles.
Another thing that can cause erratic shifting on an auto trans is a bad range switch (tells the A/T ECM what gear the shifter is in).

Add your comment to this topic!