02' Denali transmission issues...please help!

[Stredog]

This is my first time posting in a forum like this, hope I am doing this correctly.

My 2002 Denali has almost 200,000 miles on it and has been running great for years. About 3 weeks ago I noticed that when shifting from 2-3 the rpm's would get really high before it shifted. No check engine light, no error codes. All other gears were shifting great, drives fine. My husband checked the engine and found that the transmission fluid had gotten into the radiator. Took it to a shop and was told the entire transmission is failing and to get a new car. My husband decided to flush the transmission and the coolant systems, as well as add an external cooling system to stop mixing from happening again, hoping this would fix the problem. So here we are 2 weeks later and the car is running just the same as before...great, aside from the 2-3 slow shift. We checked again today for an error code, but got nothing. So my real question is, do you think we "fixed" the need for a new transmission, or are we just driving on borrowed time? I have 4 kids that I drive in this car everyday, and while it drives great at the moment I am worried it will up and die on me in the middle of the road. Would taking it to a transmission shop help give us a better idea of time left, or will they just tell us to move on while the car is still running?

Thanks!

 

[01ssreda4]

At 200k miles you are at the limit of the life of the clutches in the transmission. Just like tires or brakes, they wear over time, and eventually need to be replaced. Since you were near the end of their life, the mixing of the coolant and transmission fluid finished them off. The flared shifting you are noticing is only gonna get worse over time. The 3/4 clutch is known to be mediocre in these transmissions anyway. The best solution is a simple stock rebuild of the trans or purchase a known good used unit and swap it in to your truck. I would expect a good used working transmission to cost $500 and a rebuild could be $1k-2k depending on the shop and if they do the remove and install. It is in now way a reason to scrap the vehicle, this is a simple problem to overcome, and could happen in any used vehicle.

 

[retiredsparky]

One thing to check, were plugs installed in the transmission cooler connection on the radiator when the tubes were disconnected? Since that cooler had started leaking fluid into the radiator, there are holes in the cooler. Those holes will leak coolant out through the tubing connections if not plugged.