Transmission Problem

[Z71 Tahoe 2005]

Vehicle has 2,600 miles. Transmission shudders when converter lockup clutch engages. Dealer says problem is cracked transmission cooler within radiator and has allowed coolant to enter transmission fluid. Rebuilt the transmission and installed a new radiator. I am concerned about the rebuilt transmission. Will coolant in transmisssion fluid cause permanent damage to the tranny. Don't feel comfortable with accepting a rebuid, feel that the transmission should be replaced with a new unit. Dealer has refused to replace transmission. Dealer has denied that transmission fluid has gotten into the engine coolant. Don't see how this can be possible if the trans cooler has a crack within the radiator. What would be the long term effects of trans fluid in the coolant? Should this be taken to GM customer satisfaction for resolution?

[Haulin' 8.1]

Vehicle has 2,600 miles.  Transmission shudders when converter lockup clutch engages.  Dealer says problem is cracked transmission cooler within radiator and has allowed coolant to enter transmission fluid.  Rebuilt the transmission and installed a new radiator.  I am concerned about the rebuilt transmission.  Will coolant in transmisssion fluid cause permanent damage to the tranny.  Don't feel comfortable with accepting a rebuid, feel that the transmission should be replaced with a new unit.  Dealer has refused to replace transmission.  Dealer has denied that transmission fluid has gotten into the engine coolant.  Don't see how this can be possible if the trans cooler has a crack within the radiator.  What would be the long term effects of trans fluid in the coolant?  Should this be taken to GM customer satisfaction for resolution?

 

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If the repairs are done correctly you have nothing to fear, any parts in the tranny that are permanently damaged are replaceable during the rebuild. If the crack was thin enough that it lasted 2,600 miles chanes are that the transmission fluid would be to thick to seep out into the coolant during warm up. Then after the engine and trans are warm the pressure in the cooling system would be greater than the cooler circuit thus forcing the coolant through the crack into the trans fluid. Long term effect of trans fluid in the coolant, less corrosion in the cooling system, most likely. Trans fluid isn't corrosive, in fact it's anti corrosive and a lubricant. In small amounts it's ok.

 

I think you're probably being taken care of.

 

Vernon

[GM-Tech]

Depends on how much tranny fluid is in the coolant and for how long. Worse case, the radiator/heater hoses become soft and spongy. We had this problem regularly many years ago at Pontiac. They'd come in and it felt like the hoses were made out of sponge rubber and they were swollen quite a bit.

 

On the other side, how much trans damage also depends on how much coolant and for how long. It's not a great lubricant for the bearings and such. I don't remember for sure on the Pontiac's, but it seems to me the coolant caused the trans seals to swell, just as the tranny fluid made the coolant hoses swell.

 

Keep in mind this was many years ago and material used may have changed so that they're not affected as much (or at all) these days.