SHO won't go into 4th gear (ATX)

[kevinspann]

It's the added weight of Sam's ego.

Yeah, that'll do it.

 

[93rev2sev]

Atx tend to get worse mileage in the cold weather. Due to the converter not locking up. That thing does have a huge trans cooler on it.

Add that to the fact that, even in Alabama, a winter blend fuel may have 10% ethanol in it. And if you used premium, you gave up a little energy, too.

 

[platoribs]

22 Highway MPG (unless your driving 90+) means its time to check your thermostat and O2 sensors

 

[itwonder]

Don't worry too much. I don't know where you live, but in the mid-Atlantic region gasoline has gone to crap. Winter blend + a full 10% ethanol (not up to 10% as before, when the actual % was running around 5%). Gas mileage is down on all of my vehicles. Thanks Uncle Sam.

 

[Cl-Slick]

UPDATE!!!!! Just did the same trip and figured out the car wouldn't stay in 4th gear! It would jump in and out a few times, then just stay in 3rd. I had the tach pegged at 3k rmps at 70mph! Now what should I do?

EDIT: Did some quick searching and I'm thinking that my VSS may be bad on the count of I have no cruise, my speedo is a little shaky at some speeds and I have no 4th! Could this be it?

 

[Cl-Slick]

I figured out why I was only getting 22mpg all highway in my SHO. I made the same trip again and payed close attention to the rmps, they stayed at 3-3500k at 70-75mph. Turns out it won't stay in 4th gear, it will go in for literally a second, then jump right back out. I searched and could it be the VSS since I also have no cruise control? Any help would be appreciated!

 

[rubydist]

a bad vss will allow shift to 4th, but will often not allow the torque converter to lock (pcm thinks the car is standing still, hence no tc lockup).

I would start with a new vss and pray that it solves your issue.

 

[St Louis SHO]

Its not going into lockup. It needs a tstat on the trans cooler...

 

[Cl-Slick]

Its not going into lockup. It needs a tstat on the trans cooler...

Where can I buy the part and how hard is it to install?

 

[LJRuddy]

Its not going into lockup. It needs a tstat on the trans cooler...

I know you know more about this than I do but I have never had a tranny not lock up because it was too cold outside. ****, I just made the drive from Omaha to KC (200 miles @75mph) this week and the outside temps are at 3F with windchills near -20. My converter had no issues locking up after the initial 5-7 miles on the highway.

 

[Wakeboy1337]

Where can I buy the part and how hard is it to install?

It may just be easier to cover half of the trans cooler with cardboard.

 

[St Louis SHO]

I know 93-95 ATX will not lock up until the fluid reaches a certain temp. This car has a HUGE trans cooler on it, so it needs help to get the fluid warm enough to lock it up.

 

[rubydist]

they definitely do not lock up until the trans oil temp comes up to temp.

you should just cover the trans oil cooler for the winter, or put a thermostatically controlled bypass valve on it like St Louis SHO suggests.

 

[Cl-Slick]

Where can I get one of those?

 

[trainguy1989]

I know you know more about this than I do but I have never had a tranny not lock up because it was too cold outside. ****, I just made the drive from Omaha to KC (200 miles @75mph) this week and the outside temps are at 3F with windchills near -20. My converter had no issues locking up after the initial 5-7 miles on the highway.

Same here. My 94 ATX locks up and its 14 degrees outside, Mind you it takes longer to lock, but eventually it does.

Question, Cl-Slick, did the previous owner bypass the radiator with the tranny cooling lines?

 

[JRA2000TL]

Question, Cl-Slick, did the previous owner bypass the radiator with the tranny cooling lines?

I dunno..ask James, lol.

 

[Cl-Slick]

^ What he said.

 

[St Louis SHO]

I did not bypass the radiator.

 

[luigisho]

That's a whole lotta tranny cooling.

 

[Cl-Slick]

Now it's acting like it needs a cps or fuel pump, I can't win. Looks like it will be parked for a few months until I can get some money and time to fix it. Class starts Monday, I can't play with it this week.