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Edward, Automatic and Manual transmission rebuilder
Category: Transmissions
Satisfied Customers: 3072
Experience:  I have rebuilt various transmissions from Ford and GM and some imports.
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I have a 2003 chevy Tahoe 4.8lt and the transmission will

Customer Question

Hi Tim
I have a 2003 chevy Tahoe 4.8lt and the transmission will only go at low rpms aprx 2000 after that it will just rev up and not pick up speed. This happens in all gears
Submitted: 1 year ago.
Category: Transmissions
Expert:  Edward replied 1 year ago.

Hello, Eddie here and I will do my best to help. Have you checked the transmission fluid level? to be sure the level was fine? also, does the fluid smell burned at all? and is the check engine light on? Let us know, Thank you.

Customer: replied 1 year ago.
fluid ok, the engine light is on
Expert:  Edward replied 1 year ago.

Alright, did the check engine light come on after this problem started? What about manual L and Reverse, same problem of slippage after 2K rpms?

Expert:  Edward replied 1 year ago.

You don't happen to have a scanner where we can check the codes that are stored do you?

Customer: replied 1 year ago.
I live in the arctic with limited mechanical expertise but i have in the local garage and they are going to scan it, tommorrow
Customer: replied 1 year ago.
Can i e-mail you when i get the codes
Customer: replied 1 year ago.
In the cold weather ex. -20 degrees celcius and colder we would have to wait 15 to warm up before reverse engaged.
Expert:  Edward replied 1 year ago.

Alright, I follow you, yes, get the codes out, and we can go from there. Make sure the fluid level is good. Is this manual shift transfer case or electronic shift?

Customer: replied 1 year ago.
just 4 buttons on dash to change 4wd
Expert:  Edward replied 1 year ago.

Alright, I know it's likely not the culprit, but just put it in 4wd L and H and back to 2wd H and see if that makes any difference.

Expert:  Edward replied 1 year ago.

If you can get the codes out, that will help me figure out whats going on. Thank you.

Customer: replied 1 year ago.
The mechanic said the code was T 1-2 shift soloniod problem.
Expert:  Edward replied 1 year ago.

Alright, do you still have the problem in reverse? Reverse is a mechanically applied gear via the manual linkage, so it should not slip in reverse, you should get normal reverse engagement and pulling in reverse even if the solenoid code was present. One thing you may want to try is clearing the solenoid code , then attempting to drive the truck, see if it makes any difference and if the code comes back right away or not indicating it's a hard fault.

Customer: replied 1 year ago.
Reverse seems fine. Is their a fuse I could check that controls solenoid 1-2
Expert:  Edward replied 1 year ago.

Yes, but it powers up the others as well. Look at this diagram and check these fuses.

Customer: replied 1 year ago.
The truck is still in garage waiting for filter and gasket to flush tranny and check solenoids.
Expert:  Edward replied 1 year ago.

Alright, did they check all the fuses, Is it right on a shift point that it acts like it flies into neutral? such as 10-15 mph where 2cd gear shift point would be? If you get the shift point and it flies into neutral, then that is likely internal, and the shift solenoid does work and makes the shift, but fluid pressure, or piston, or band is not applying causing the transmission to give the symptom of going into neutral at the shift point.

Customer: replied 1 year ago.
Just got a call from garage the filter had fallen off and was in the pan. fluid dirty with clutch debris'he put new filter and fluid but the same code still appears and it is acting the same so i guess the wife burnt the tranny up. lol I am looking for a new one now (tranny not wife). Thanks for your advise. Dave
Expert:  Edward replied 1 year ago.

LOL, OK David, yes, if they pulled the pan and it's got shrapnel in it, It'll have to be rebuilt or put a used unit in it, Sorry it wasn't something a little easier sir. Let me know if you have any further questions. Thank you!