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Need help with a 08 Silverado

It started on Monday, me and my dad was on the way to work when the hose going from the transmission to the radiator popped causing transmission fluid going everywhere. ( the last guy just had the rubber tubes on them clamped instead of being pressured fitted). When we came to a stop i guess the fluid caught on fire but we where able to put it out pretty fast. So we got the truck towed back home. We where told it shouldn’t have damaged anything beside hooking the connections back up so, yesterday we switched both tubes coming from the transmission to the radiator and the cooler thing and filled it back up with transmission fluid. all was good so we thought
Today it drove fine for about 2 hours then out the blue it started to slip when you where going anywhere from 30 to 45mph anything befor and after the truck ran heavy but it dint slip, we tried putting another qrt of transmission fluid in it but dint effect it. We’re drove it back home because we just hit a tow and dint wanna get another but as soon as we turned down our street the motor started running harder and shaking and po 307 it’s popping up we moved everything around and it still the same Cylinder 7 misfiring I have no clue and is it even worth fixing

Idk if it’s important but when waiting for the tow truck and having our emergency lights on it did kill the battery but after getting a hotshot it worked fine

If the transmission is overfilled it can cause the problems you are having. But then if the transmission cooler is plugged it can also cause the problem. And regardless what the cause of the problem is continued driving will totally trash the transmission.

If you have access to regulated air pressure you can remove both cooling lines from the radiator and apply about 10 psi of pressure to ensure that air will flow freely in both directions. If the cooler tests OK you need to PROPERLY check the fluid level. And on automatic transmissions it’s better to be a quart low rather than a quart over full.

If there is rubber hose on the transmission cooler it could be fuel line which will emulsify when carrying hot transmission fluid. Only hose rated for transmission fluid can be used. And if the cooler is not blocked you might disconnect both lines at the transmission and blow through them. Emulsified rubber hose can plug up the metal lines.

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I’m thinking the fire has done some damage to the wiring harness, necessary signals aren’t getting through to the computer now, and that’s the cause of the misfire and transmission symptom that both appeared out of the blue.

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The transmission cooler is fairly new it was switched over the summer along with the catalytic converter

But it drove perfectly fine for awhile so I would think the wiring harness is fine

Did you have the radiator tank removed and get a new cooler installed or replace the complete radiator?

In that case what I would do if I had that problem (beyond checking for powertrain codes) is a routine-maintenance transmission service; i.e. if so-configured, replace fluid/filter/clean pan. If that significantly helps but doesn’t solve the problem 100%, do it again after driving a hundred miles or so.

Just the cooler its in front of the radiator like a smaller radiator. im pretty sure that’s the radiator cooler

We drained some of the transmission fluid it helped calm the motor down its not shaking as hard but it still has a missed sound. It still slips or sounds like it will not go out of 2ed gear.
We switch the spark plugs just to try and it dint effect it it kinda looked like the 7th cylinder spark plug is getting wet some how(maybe the head gasket is cracked idk) but it’s on the opposite side of the truck where the transmission fluid originally sprayed

Some car mechanic tried to say we got bad gas and put some stop slip in with the transmission fluid and get some dry gas but it dint help either

We took it to a transmission shop they said we burned 3rd gear does that sound about right?

Third gear doesn’t “burn”, but the mechanism that actuates third gear, in this case the direct clutch, can burn out. It doesn’t much matter, because at this point, you have three choices. 1) have your transmission rebuilt by your independent transmission shop, 2) have your mechanic install a used transmission that he sources for you. 3) have your mechanic install a remanufactured transmission from a place like Jasper. Your money, your choice.

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I don’t see how a minor fire in the engine compartment would “burn third gear”. The mechanisms for engaging third gear inside the transmission, seems like they would be pretty robust compared to a minor engine compartment fire. I’d guess if the fire had anything to do w/it, more likely something external to the transmission was affected by the fires.

When the cooler line came off, the truck must have been driven for a minute or two, insufficient fluid pressure could have caused the third gear clutches to slip and burn up.

As Nevada and old-mopar-guy stated the ‘gears’ weren’t burned. The description indicates that the clutch on that gear is wiped out and the transmission must be rebuilt or replaced.

As for the cooler…Look at the small cooler. Are BOTH cooling lines from the transmission connected to that cooler or is there a connection into and out of the transmission and then into the external cooler?