Auxilary Transmission Pump Failure
 

I am hoping to get my Tahoe back tomorrow after two weeks in the shop. First the pump failed for the second time then the control module died. There were none available in the US according to the service department. This does not bode well if parts are not available for two weeks. Has anyone else had transmission pump troubles?

yikes!
 

did you have the option of a whole trans assembly, seems to me that they could pull one off the line??
Im sure hoping these are all one off problems...

Re: Auxilary Transmission Pump Failure
 

Today the truck came home. They finally pulled the part off of a Tahoe on the lot. We'll see what happens.

Re: Auxilary Transmission Pump Failure
 

how much was it? i mean the total repair of the whole auto parts? Was the damage really that bad? you might want to have a second opinion about it.

Re: Auxilary Transmission Pump Failure
 

how familiar this sounds....

What is this famous pump, what does it do? is this the same as the auxiliary water pump?

Re: Auxilary Transmission Pump Failure
 

It's the same part you're having problems with, delasierradh. The trans aux pump maintains trans fluid pressure in autostop when the engine-driven primary pump is not running. Since this trans has wet plate clutches, you need sufficient trans fluid pressure to keep them engaged.

Re: Auxilary Transmission Pump Failure
 

When the pump dies the truck won't run as a hybrid. It only runs with the gas engine, no autostop, etc. It should be a warranty item, they did have problems with early build dates and the replacement part fixes the problem. The dealer was very accommodating, they had the truck for quite some time but gave us a loaner.

Re: Auxilary Transmission Pump Failure
 

Well you don't autostop or have EV-only drive, which admittedly is a big part of owning a hybrid, but the electric motors still provide a lot of functions even when the engine is running. You still get the benefit of torque boost that can keep the Engine in V4 mode vs. V8, you still have launch assist, you still get regen braking, etc. Point is the motors aren't just dead weight, they are intricately tied into the whole system. But I get it; when you have a hybrid you want to sit in traffic snarls with the engine rarely running, you want full A/C with the engine off, and you want to go thru subdivisions and parking lots in silent mode. It's cool, esp in a big pickup or utility.

Glad to hear your dealer treated you well, ray. With the low volumes like these trucks are right now, and the cost of keeping parts on the shelf, I guess I'm not surprised they don't have hybrid-specific parts available at hand.