Allison 5sp: Smoking Stock 5 Speeds Too Quick?

[RobsDmax]

In my pull truck. Likely 600 HP on a good day. 3rd gear starts 4 low, I burnt out the stock one last season after likely 70 hooks. That was no problem I figured hey it lasted this long I am good to swap another stock one in. Bought a used one, swapped it in and ran about 8-10 hooks on it and street drove to pulls (never limped) and then smoked it again. When I smoke them the truck will drive in neutral, and wont shift to 4 low unless not running. Am I melting clutch packs, or converter? I pulled again this weekend on another stock one I picked up, and it appears I have done the same thing again. Wondering if there is something wrong more than just the trans? Or if I am just hurting them because I push them too hard.

 

[Mike L.]

:banghead::banghead::banghead::roflmao:

 

[RobsDmax]

I was actually asking a serious question. I understand its not recommended to pull on a stock trans, just wondering why the stock one lasted sooo much longer than the other 2.

 

[RobsDmax]

Trans Woes

Seeing as all Mike wants to do is laugh I will ask here as perhaps you guys understand more about the sled pulling side of things.

In my pull truck. Likely 600 HP on a good day. 3rd gear starts 4 low, I burnt out the stock one last season after likely 70 hooks. That was no problem I figured hey it lasted this long I am good to swap another stock one in. Bought a used one, swapped it in and ran about 8-10 hooks on it and street drove to pulls (never limped) and then smoked it again. When I smoke them the truck will drive in neutral, and wont shift to 4 low unless not running. Am I melting clutch packs, or converter? I pulled again this weekend on another stock one I picked up, and it appears I have done the same thing again. Wondering if there is something wrong more than just the trans? Or if I am just hurting them because I push them too hard.

 

[Mike L.]

I was actually asking a serious question. I understand its not recommended to pull on a stock trans, just wondering why the stock one lasted sooo much longer than the other 2.

According to your first post all 3 were stock. What condition were the other 2 stock ones?

 

[RobsDmax]

Yes all were stock. First was the original, second was a used as was the 3rd. Condition unknown. Yes I should have tore them down, although I did not figure most people would be too hard on 3rd gear. I was more wondering what I am melting.

 

[fast03]

I am no expert, but I would say a 3rd gear start is what is hurting them

 

[Chevy1925]

they are stock....... and they are unknown condition. that pretty much answers it all. unless you disassemble these "unknown trans" to determine there health, they could last 1 pull or they could last another 70. your trying to read a book with it shut

 

[Burn Down]

Am I missing something? Why the heck would you want to run a stock trans. at 600hp pulling or not?

 

[DAVe3283]

In Mike's defense, that is kind of a funny situation... Since you have pulled out a couple transmissions so far, why are you asking us what is smoked inside them? Open them up and tell us!

As for the root cause, yes, you are hurting them because you push them too hard. How long you can get away with that is luck of the draw.

As to why the replacements get smoked quicker than the original, I am going to speculate that you are only replacing the trans, not the TCM, and aren't doing a full (Tech2) relearn either. So the TCM thinks you have a trans with basically no clutches left, and starts applying them earlier to compensate. Except now you have full clutches ("new" trans), so it creates a tie up. Which you don't notice, because you are at ~600 HP, so the clutches just slip, heat up, and burn out in a matter of a few shifts, instead of 70.

But I'm not a trans guy, this is just speculation based on what I have picked up watching things break.

 

[DAVe3283]

Am I missing something? Why the heck would you want to run a stock trans. at 600hp pulling or not?

Maybe he has an unlimited supply of them for free? And free labor swapping them out?

I'd personally think that by the 3rd trans, it would have been cheaper to just put a built one in, what with the labor and all. Or if not cheaper, then at least less frustrating!

 

[CentolaCCSB]

Or spend the money on 3 stock trans when u could build one for the same price

 

[Burn Down]

Maybe he has an unlimited supply of them for free? And free labor swapping them out?

I'd personally think that by the 3rd trans, it would have been cheaper to just put a built one in, what with the labor and all. Or if not cheaper, then at least less frustrating!

Or spend the money on 3 stock trans when u could build one for the same price

That's what i was getting at. Just doesn't make sense to me. I know you can get away with it pulling for a while but 3rd time in I would be pissed at myself.

 

[Ne-max]

I would keep trying stock ones tell you get one that holds up...

 

[Kat]

I merged the threads :hello:

 

[Mike L.]

What we have here is stock transmissions in questionable condition. 4 C3 clutches ( not enough ) that are probably worn. 6 C1 clutches ( not enough ) and probably worn. Line pressure 230 psi if you're lucky with a 100 psi drop when the converter locks. That means you are sled pulling at 600hp with 130psi line pressure.

 

[IOWA LLY]

Did you start in 3rd gear with the one that lasted 70 hooks?

Sent from my SM-N920V using Tapatalk

 

[whiterock06]

I think somebody likes to break things


06 Crewcab long bed Lbz

 

[ikeG]

These threads irritate me. Not for the reason you would think. Why can he not get the correct answer the first time? It was a legit question. He knows the ridiculousness of swapping 3 trans already, he's not looking for counseling or ridicule for that. The peanut gallery always chimes in with nonsense. A high post count on here anymore doesnt necassarily mean you're knowledgeable. This forum is supposed to be for problem solving and q&a and tech.

 

[RobsDmax]

I was going to make a reply to each one however I won't. Yes I know its ridiculous too pull on stock trans, I am asking what I have broken. For what I paid for the stock trans I have swapped in (300 and 400) I could not have built a trans. I swap them myself. I have a kit ordered to build one over the winter was just wondering why 1 would go 70 hooks then 6 and 3. I have those answers now and will continue with my plans to build one this winter. Thanks for all the input......