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Replaced transmission

Please help! I just replaced my transmission because it was slipping, clunking and finally would rev really high with no ability to accelerate on steep incline. It has 145,000 miles on it. Overall, it si working 100% better except it did the same thing regarding reving up when accelerating on steep incline. I went back to repair shop and they could not replicate. Also, it sounds like crinkled aluminum foil while you are driving under car. Thank you!

Make sure to get your new transmission working properly while it is under warranty from whoever installed it. Is the replacement a NEW transmission, a REBUILT transmission, or a USED transmission? If it is new or rebuilt it should work properly and may need some adjustments to clear the problem. If it is a used transmission then the condition of the replaced transmission could be subject to question. Used transmissions are tested to see if they function properly but sometimes these tests are not the same as real life conditions.

Assuming the trans is OK, it is supposed to let the motor rev up as you climb a steep incline. Your motor has the most power at 3,000 rpm and higher and the transmission stays in a lower gear to keep the motor rpm’s up until the grade flattens out. So reving without slipping is OK, while reving due to slipping is a big problem. From here I can’t tell if your “reving” is normal or not.

Not only does it rev up and I lose all power when I press on the gas, it makes this horrible noise under the car, the same situation as it was BEFORE i replaced the transmission. Even though the auto shop took the car out for a test drive and could not duplicate the problem, that does not give me great comfort when I am driving up the canyon with an 18 wheeler behind me and it happens again. I am under warranty and it seems like the rebuilt transmission is not 100%. They seem completly puzzled but I think I am going back and not waiting for it to happen again.

I don’t know how long you’ve owned the Suburban, but a rebuilt trans should function in the same way as when the truck was new. It should shift smooth, and you should have plenty of pull up any hill as long as the motor is running well. From your post it doesn’t seem like you trans is working even close to what it I’d expect. Take it back, and make them drive it on the kind of roads you drive on. A quick trip around the block won’t do.