Ok... So, overdrive, and the lock up torque converter are two different things, no?
Get up to 60mph... Tap the brakes... No difference whatever in RPMs.
But, get to 60... RPMs are ~1500-1600... It has definitely shifted into 4th. Now, push the overdrive button on the stalk... Immediate change in the transmission, and immediate jump to at least 2200 RPMs.
So, I am thinking the trans is shifting into 4th, just fine, (overdrive), but the TC is not locking up.
Unless the two are "synonymous". As in, if it shifts to 4th the TC locks up. Together that constitutes overdrive. Hit the button to turn off overdrive, and it unlocks the TC AND shifts the trans back to 3rd...
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Also today: Brake light and ABS light both come on when the key is turned. The ABS light goes out. But the brake light stays on forever.
Also, first time applying the brake, at startup, brake pedal goes way down, and is spongy.
For the remainder of the test driving, the brake pedal travels further than I think it should, but the brakes stop the truck admirably.
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On a steep incline, it rolls like normal.
On a slight incline, even on pavement... You have to put it in drive for a second to barely get it to rolling... And then it will roll very slowly. Like the brakes are barely applied. It SHOULD roll slowly at first, then gain momentum. It doesn't.
Plus, you have to have your foot on the gas pedal all the time, or you lose forward momentum.
At times on the highway, when you should be able to let up on the gas and coast... It immediately slows down, like you have your foot on the brakes.
Takes more gas pedal to get up to speed, than I think it should.
All in all, it just really acts like the brakes are always slightly applied.
I am going to ask them to check the pushrod in the master cylinder/vacuum booster.
And check the brakes again. As well as the bearings.
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In a little bit, I'll go out there and use the OBD reader, to see if there are any codes stored. The OD light didn't flash when I put it into 4wd this time. Only difference this time is that I put it in 4lo instead of 4hi.