Jump to content

Transmission Problem

Z71 Tahoe 2005

Recommended Posts

Z71 Tahoe 2005 New Member

Z71 Tahoe 2005

Posted
Posted

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 Enthusiast

Haulin' 8.1

Posted
Posted
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?

 

 

 

 

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 Senior Enthusiast

GM-Tech

Posted
Posted

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.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • richard wysong
      Electrical Problem - solved

      By richard wysong · Posted

      Thanks for posting, I'm sure it will help someone
    • Brendan C
      2026 6.6 L5P oil cooler leaking oil at 4,000 miles

      By Brendan C · Posted

      New to diesel trucks. I happened to find my oil cooler leaking oil externally with only 4,000 miles on the truck. I didn’t realize this was an issue until I started researching it. Dealer is going to replace it under warranty but I’m wondering if there’s anything GM is working on to fix this issue. I’ve heard the oil filter used is the same as they use on their V6 motors and that’s what is causing the problems. Should I switch to a bigger filter or keep using the OEM recommended? 
    • Vu1can
      Seems to be Missing a lot of Updates

      By Vu1can · Posted

      So, GMCustomerService:  Judging by the Update History pictured above, is this truck missing any updates that it actually needs. If it's just for the infotainment system, the radio is working fine and no trouble with SeriusXM. and Android Auto is working fine wirelessly with my phone. Some months ago, an update notice was sent to my truck. I approved the update and it finished saying that the update was successful, but it seems that whatever that update was, it didn't actually get installed - at least not if I'm to go by the Update History shown above.   So, again, are there any updates that this truck really should have? I've checked with my dealer but they're reluctant or commit to anything and if I want them to check, they require a $200.00 fee just to check it out and then I'd have to pay for the actual update(s).    Ignorance is bliss, and if none of the updates goes to fixing any mechanical discrepancies, I'll just leave things as is.  
    • CNH-320
      Electrical Problem - solved

      By CNH-320 · Posted

      Hey everyone, I recently had an issue with my 07 2500HD GMT900. My DRL’s stay on at all times. Right front turn and right mirror turn signal indicator stay on solid at all times. By “at all times” I mean the only way to make them go off is disconnecting the battery. I tore the headlight assemblies out, tried disconnecting the harnesses to eliminate bad wiring at the harness, I unplugged the headlight switch, no change and the mirror turn signal still stayed on. My first thoughts were : Bad bulb and/or socket somewhere, under hood fuse panel bad, bcm bad, tail light or trailer wiring problem, or some random short to power in the harness.  Possibly a bad ground but unlikely. I had a big clue in the fuse panel, it had a burnt smell. I started pulling every fuse that had to do with DRL or right turn/park lamp. Nothing made the right directional turn off but pulling the DRL2 fuse made the DRL’s go out.  After studying wiring diagrams, I found that both problems had that fuse panel in common, the bcm also controls both problems but knowing the fuse panel had a burnt smell I removed and disassembled the fuse panel and found a little corrosion on the printed circuit board.  I ordered a new fuse panel from Amazon for like $260. When it arrived I installed it, and put everything back together, the problem was fixed. I figured the fuse panel needed to be replaced anyway so that was a logical place to start. Hopefully this story helps someone in the future. Regretfully I didn’t scan for codes before I did everything.
    • 2022LtTbZ71
      Service 4wd, ESC light, traction control light on, Service charging system (vehicle may stall)

      By 2022LtTbZ71 · Posted

      That stinks. I’m sitting on the side of the road right now with the same issue. Never had an issue before taking it in for the ground strap recall. Now I’m outside of warranty and they’ll probably want $200 just to diagnose what they already “fixed”. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...