TH125 (non-H-body) 3-speed transmission troubles

[gerbsinmd]

Reid,

It probably depends on how you drive it, whether or not you notice a diff in mileage, I think that you probably would notice a difference though. I replaced that same solenoid on my Lumina, the part wasn't that expensive and it only took a couple hours. The thing to think about is how long would a 2 mpg increase to pay off the $75 the parts cost?

Darrel

[barebonesracecars]

Reid,

It probably depends on how you drive it, whether or not you notice a diff in mileage, I think that you probably would notice a difference though. I replaced that same solenoid on my Lumina, the part wasn't that expensive and it only took a couple hours. The thing to think about is how long would a 2 mpg increase to pay off the $75 the parts cost?

Darrel

Only a couple of weeks if it was my truck!!!

I'm looking to get at least 28 mpg in this car, which should cut my fuel bill almost in half, and pay for the car in about 12-14 months.

[Elfmagic]

I know that it will hurt the milege quite a bit becouse these TC stall pretty high, my sister had a 89 grand am I had to do the same thing to and it only go about 22-25mpg on the highway, not hardly worth the 4 cylinders when I was getting 28mpg on the highway with my carbed 84 z28.

[barebonesracecars]

I'll know Friday what the mileage is going to be. Several people have told me to expect up to or around 28, but I do have some hills between home and work.

[barebonesracecars]

Just over 24 mpg this week, keeping my foot out of the hairdryer, but with a bad oxygen sensor (rich code) and the TCC unplugged.

Shifted fine. Will put the O2 sensor on next week and see if I can gain another mpg or so.

Thanks again, gentlemen.

[heinz057]

before you change the o2 sensor check the vacuum hose for the map

[barebonesracecars]

Will that set the code for a rich 02 sensor?

[heinz057]

it can because the engine is running lean and the o2 is trying to make it rich so now the o2 tells the computor to put more fuel . if the hose is ok it can still be a bad o2.but chsck for vacuum leak first

[barebonesracecars]

I'll check that out.

So, apparently the codes are not fool-proof? Or is that a symptom of the cheap code scanner I'm using?

[heinz057]

you need to read data also not just get a code number . the data stream will tell alot. the code is just the starting point.

[classic_cruiser]

I had this happen on my 1990 cavalier with 170K on the clock, unplugged the TCC solenoid connector and ran it for 30K before I fixed the solenoid. Same thing recently happened to my '87 cavalier, although this one I changed the solenoid sooner. The only differences I have seen are that if you do a lot of driving around 30-40MPH (right where the TCC would normally lock) your car will waste a bit more gas, I lost about 3 MPG. At highway speeds there's only about a 100 RPM difference, even going uphill.

I have heard that the transmission does run a little hotter too, and I've seen it in my 2 cars but it didn't make much of a difference. If your trans is marginal it might be a bigger concern.

Changing ther TCC is simple, you can get one for about $10-$15 plus the side pan gasket and do it yourself in about 1-2 hours, about all you need to remove is the front tire to get to the side pan.

Terry