Broke a built 6R80 on the street... 2ND TIME

I've posted what happened with my car here and there but I got several questions so I figured id keep a log here of what has been going on.

Last week I was getting on the highway, somewhat distracted talking to my passenger. I went about 1/2 throttle while the car was locked in 5th gear. By the time I realized I wasn't going anywhere fast I looked down and realized I was at 8psi in 5th. Let off the gas and upshifted, car died. Coasted to the shoulder and tried to start it. Nothing, no crank, no start. Pulled plugs and belt, couldnt rotate the crank with a breaker bar with shifter in N, figured I'd seized the motor from going into boost in such a high gear, even though it was only for a few seconds...

Got it towed to JPC for a built motor. They verify the motor is locked up, pull it, and discover that the input shaft of the trans is locked up and my motor is fine.

Car has 37K on it, supercharged since 6k. My original trans broke at 9k and was rebuilt by another shop. Circle D, Intermediate shaft, and clutches all upgraded. I have never heard of a built 6R80 breaking on the street. Anyone have any ideas?

At this point now the trans came out and I'm waiting to hear the verdict on it, but I already paid the labor to remove the motor, so depending on the cost of the trans repair I'd like to just build it anyway while it's out.

UPDATE on Page 2 Post #27

Well we're just having all kinds of bad luck lately. Sorry to hear that.

Agreed, since the motor is out and labor paid for, might aswell get the motor built. You would be kicking yourself if the motor let go in the near future and you have to repeat the process (and expense!)

That sounds all good and peachy when we are just giving are opinion.I mean if u have the extra money then yea it makes sence,but if it is going to put u in bind then i would not do it just based off the motor is already out.Believe it not their i s not that much to pulling one of these motors.Thats crazy the trans broke in 5th and that low of an rpm even though the motor had a good load on it.I tbink something was not done right on the rebuild and it should be covered.Just doing a bottom.end with no sleeves is probably going to be over 3k with parts and labor and that may be on the low side.

Also another factor hear is if the transmission gets fixed under warrenty,it should and i would fight real hard to make sure they make it right.If the trans is fixed under warranty then i would try to do pistions,rings, and rods to make a strong shortblock.

This is the exact scenario I have seen break the trans the most. The taller gear and boost at low speed is a huge load. I recently sold my twin turbo car and told the buyer a dozen times. Any street hits make sure you manually put it in the right gear, go wot, and then put it in drive.

I wouldn't waste money on a build unless you put in sleeves....Thats the next thing you will hear while your in there put in sleeves.

Sorry for my ignorance but I'm trying to understand what happened. You were in gear select mode and had it locked in 5th? Hoping to understand so I can avoid it. I almost always just let the computer shift for me so maybe I won't run into that issue. Can't imagine losing my trans twice, much less once, so sorry for your bad luck.

Reds197 said:

This is the exact scenario I have seen break the trans the most. The taller gear and boost at low speed is a huge load. I recently sold my twin turbo car and told the buyer a dozen times. Any street hits make sure you manually put it in the right gear, go wot, and then put it in drive.

I wouldn't waste money on a build unless you put in sleeves....Thats the next thing you will hear while your in there put in sleeves.

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What are the plans for the 18?

Brian Z. said:

Sorry for my ignorance but I'm trying to understand what happened. You were in gear select mode and had it locked in 5th? Hoping to understand so I can avoid it. I almost always just let the computer shift for me so maybe I won't run into that issue. Can't imagine losing my trans twice, much less once, so sorry for your bad luck.

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Yes, I was in S paddle shifting the whole drive, I went from cruising for a long period of time to getting on an on ramp to the highway. When I accelerated on the on ramp I forgot it was locked in 5th and didnt downshift on it's own like usual.

Reds197 said:

This is the exact scenario I have seen break the trans the most. The taller gear and boost at low speed is a huge load. I recently sold my twin turbo car and told the buyer a dozen times. Any street hits make sure you manually put it in the right gear, go wot, and then put it in drive.

I wouldn't waste money on a build unless you put in sleeves....Thats the next thing you will hear while your in there put in sleeves.

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The shop did tell me not go go WOT in 5th or 6th, but this was 1/2 throttle, maybe 2/3 at the most. I can't imagine 1/2 throttle in 5th is that much worse than WOT in 4th for a dyno pull.

It's my own fault for going into boost in 5th gear but I still can't believe it couldn't handle 1/2 throttle for 5 seconds.

Tommy V said:

That sounds all good and peachy when we are just giving are opinion.I mean if u have the extra money then yea it makes sence,but if it is going to put u in bind then i would not do it just based off the motor is already out.Believe it not their i s not that much to pulling one of these motors.Thats crazy the trans broke in 5th and that low of an rpm even though the motor had a good load on it.I tbink something was not done right on the rebuild and it should be covered.Just doing a bottom.end with no sleeves is probably going to be over 3k with parts and labor and that may be on the low side.

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Tommy V said:

Also another factor hear is if the transmission gets fixed under warrenty,it should and i would fight real hard to make sure they make it right.If the trans is fixed under warranty then i would try to do pistions,rings, and rods to make a strong shortblock.

Click to expand...

Well it's not at the shop that the trans got rebuilt, so warranty isnt going to be possible. Also as far as I know there never really is a warranty with "racing" parts anyway.

I definitely don't have the extra money but I figure it has to be around $1500 labor to remove/reinstall the motor? Plus since my block is all good I think they said it's worth $1400, significantly more than after it breaks. If I don't build it while it's out and it goes later, I'll be wasting almost $3k. :tsk:

SoCalTim said:

Agreed, since the motor is out and labor paid for, might aswell get the motor built. You would be kicking yourself if the motor let go in the near future and you have to repeat the process (and expense!)

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Yeah, that's what makes me really want to build it while it's out. It's all dependant on how much the trans costs to fix though. If it's $6k+ again like it was the first time, I won't be able to afford anything with the motor and I'll have to eat the useless labor.

SolarFlare said:

Well we're just having all kinds of bad luck lately. Sorry to hear that.

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Thanks man, seriously. In the same week my daily's rear caliper seized and got a nail in a tire that I have to add air to twice a day lol.

5th is overdrive. 4th is 1 to 1. There is a big difference especially at low speeds. Hitting boost in 5th at 150mph won't kill it but boost at low speeds will.

I’m now thinking I was in 5th at wot when mines gave out based on length of pull on mph. No more 5th for me that’s for sure.

Yeah, that's what makes me really want to build it while it's out. It's all dependant on how much the trans costs to fix though. If it's $6k+ again like it was the first time, I won't be able to afford anything with the motor and I'll have to eat the useless labor.



What was 6K to begin with. Was it 6k to pull the trans and build it?

Reds197 said:

5th is overdrive. 4th is 1 to 1. There is a big difference especially at low speeds. Hitting boost in 5th at 150mph won't kill it but boost at low speeds will.

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Yeah I guess so. Still surprised me a built trans can't handle it though

SolarFlare said:

I’m now thinking I was in 5th at wot when mines gave out based on length of pull on mph. No more 5th for me that’s for sure.

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Damn, your problem is with 4th though right?

kcc0521 said:

What was 6K to begin with. Was it 6k to pull the trans and build it?

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It was over $6k to get my 6R80 built when it broke the first time

Sorry for your loss but thanks for the 411 on what not to do- I really did not know .

Unfortunately I do know too well about bad luck with these cars .Stories like this just want to make me cut my losses and sell.

kcc0521 said:

What are the plans for the 18?

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I have recently opened my own shop in KC area. I am looking to showcase what the 18 is capable of when set up right. Whipple or a TT Kit and a 8 second pass on stock parts is my goal.