Erratic shifting auto trans

Hello all,

First post here. My son was gifted a 1995 Tacoma v6 4x4 auto trans by his grandfather. The truck has been solid until recently.

The truck started a type of hesitation when accelerating from 1st to 2nd gear after the truck warms up. From a stop under normal acceleration the truck shifts out of 1st into 2nd and as its building rpms and speed it will start to hesitate. The rpms will fluctuate up and down like if it is trying to decide what gear to select or what RPM to be at. I don't push it at all and let it settle down and will usually settle down and drive normally. Once it gets up to 45-50mph and up no hesitation at all, I can speed up and overtake if I have to without issue. Once I stop at a light the issue repeats itself. As I said before the issue only comes up once the engine gets up to temp after about a few miles. I changed the TPS and the MAF sensor and the problem is a bit better but still starts to creep in as the truck gets up to temp.

Any ideas??

 

That's tricky... Could be a few things. Do you have a maintenance history for the vehicle to find out when the last time the ATF was changed? I know there is a temp reading being sent to the ECU that plays into shifting logic, but I am not sure of it's location, or even if a 95 would have that. I know for some where around 97-99 and prior, the SCII can't pull a transmission temp and physical gauge has to be installed.

I am thinking somewhere along the lines of, either a bad temp sensor, bad fluid, or bad shift solenoids.

Changing the fluid poses risks, but most consider a drain and fill to be safe. Drain and fill as opposed to a pump assisted change where new fluid is forced through the transmission.

I did a quick search, and came up empty with a temp sensor location. I know it's at least got to be there on my truck cause the SCII gives me a reading, but again, no idea on a 95.

I would consider the drain and fill- three of them actually spaced out @ ~1k intervals ... one to get some new fluid in there, then another to change out more fluid, and a final where I would drop the pan and change out the filter along with the drain and fill.

 

Thanks for the reply. I do not have any records for any services other than oil changes, brakes and tire rotations. I checked the fluid levels both cold and after 15 mile normal city driving. The fluid level is where it should be and the fluid looks good and doesn't smell cooked. I have been suspecting bad shift solenoids. Gonna take it to my buddies shop for him to do a drain and fill and replace the solenoid to see if that solves it.