6l90e Problems?

[OneTwo]

whats the reasoning behind not doing a flush? just asking, I've never had this 6spd. Just draining and filling you're only getting about 1/5th of the fluid changed (if this is a normal automatic...)

Most people say that it dislodges materials that can end up blocking narrow passages or one-way valves and can actually harm your transmission. Some transmissions have a "lifetime" fluid that must retain at least 50% of it's original fluid or it will fail (my old BMW E34 auto was this way - or at least that's what I was told - I have no idea why).

To be honest, I'm not entirely sure why not to flush one of these transmissions. When I was researching the 6L80E, I came across multiple "DO NOT FLUSH THE TRANSMISSION" comments and exactly zero comments saying that you should.

 

[63Blackseries]

I brought my truck to the dealer. Hoping they would replace the slipyoke since I am still under power train warranty but the crappy dealer says they did not hear or notice anything wrong. In this case what can I do to fix this annoying clunk?. The TSB says 4wd Trucks cannot be greased?

 

[Denalievv]

Have you figured this out yet?

 

[drakon543]

Felt like chiming in regarding this transmission flush side topic. Most people i know that swear a dealership "flush" service is bad for your transmission are under the impression that a foreign cleaner is being sent through your transmission. Most dealerships that i managed to actually talk to a tech have informed me that no cleaner is actually being introduced to your transmission. As stated above doing a diy pan drop and filter change your only getting a portion of the fluid changed. As the process was explained to me all thats happening is new fluid is being pumped through the transmission in the same method as when your driving. It continues to collects the old fluid in a separate container until only clean fluid is coming through. In my opinion the discussion of having a flush done is being misinterpreted with the old method of actually adding an extra harsh cleaner that would indeed free up gunk and possibly lodge it where it shouldn't be.

 

[drakon543]

As a side note not all shops have the machine capable of doing this new method of changing your transmission fluid.

 

[gtp1500]

On my way home after buying mine I floored it to pass someone and felt the clunk... now I'm sure its the motor mount, I did the brake test and the motor flexed pretty good.

 

[OneTwo]

On my way home after buying mine I floored it to pass someone and felt the clunk... now I'm sure its the motor mount, I did the brake test and the motor flexed pretty good.

Mine did the same thing and it is all gone now that I've replaced the driver's side motor mount. What a relief!