Trans feels like it's slipping.

[Philv]

My lb7 has 268k miles and the trans every so often it'll feel like it's slipping, but never goes to limp mode of throws a dtc. Also sometimes it'll shift nice and firm other times it'll shift very smoothly. I've also noticed it does it more under half- full throttle, could the TC be failing? I'm running amsoil low viscosity in it.

 

[DAVe3283]

A healthy stock Allison will never have a firm shift. They will shift smoothly if everything is working right. Firm and hard shifts can easily break hard parts. On a good built Allison, they will shift pretty smoothly even with big HP.

So if you are feeling some firm shifts, it might be a warning sign. I lost a transmission when the trim springs broke (found that out later), and the ECU couldn't control the shifts well. It shifted firm, which I didn't know was a problem, so I ignored it until one day it just broke a shaft on a 30% throttle 3->4 shift leaving work.

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[Philv]

A healthy stock Allison will never have a firm shift. They will shift smoothly if everything is working right. Firm and hard shifts can easily break hard parts. On a good built Allison, they will shift pretty smoothly even with big HP.

So if you are feeling some firm shifts, it might be a warning sign. I lost a transmission when the trim springs broke (found that out later), and the ECU couldn't control the shifts well. It shifted firm, which I didn't know was a problem, so I ignored it until one day it just broke a shaft on a 30% throttle 3->4 shift leaving work.

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Yeah I plan on doing a built trans, but first is fixing my injectors. Looks to be roughly 10-11k I need to put into the truck to be mechanically sound. Hope I can get this job I just applied to cause then I could afford that and more. Lol

 

[torqued2dmax]

My lb7 has 268k miles and the trans every so often it'll feel like it's slipping, but never goes to limp mode of throws a dtc. Also sometimes it'll shift nice and firm other times it'll shift very smoothly. I've also noticed it does it more under half- full throttle, could the TC be failing? I'm running amsoil low viscosity in it.

Why are you running low viscosity in AZ I would have thought it would be for cold places ?

 

[Philv]

Why are you running low viscosity in AZ I would have thought it would be for cold places ?

That's what amsoil recommends. My brother also runs low viscosity in his lbz.

 

[TheBac]

If you think it's slipping now, that lift and big tires you're now talking about will kill it. Start saving for that rebuild.

I would've just put Dex3 or Transynd in it and called it a day.

 

[DAVe3283]

I would've just put Dex3 or Transynd in it and called it a day.

This x100

The Allison is one of the first clutch-to-clutch transmissions made, and as such it is picky on fluid more than most for holding power and shift quality.

Dex3 is cheap and readily available, and is what I run. It works perfectly, as that's what it was designed for. Transynd works great too, and lasts longer between changes, but is hard to find and expensive, so I don't think it is worth the hassle.

I wouldn't run other fluids in the Allison, even if Amsoil says too. They are in the business of selling their oil, not saving you money.

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[torqued2dmax]

Viscosity to a point is to protect parts , low viscosity high temps = broken or warn out parts . Do not run WOT in 5th till you are ready to slug your way over to Mike Ls , its on its last leg .

 

[Philv]

Just a little update. I did a drain and fill with amsoil torque drive, and the trans shifts much better. I didn't realize how much it was slipping until it grabbed with the torque drive. I just hope when I have the cash and do the 45% sac injectors, the trans won't explode.lol

 

[zakkb787]

Your tuner can keep stock power levels with the new injectors.

 

[Philv]

Your tuner can keep stock power levels with the new injectors.

Which tuner will do that? I'm not running one and have been looking for the right one.

 

[zakkb787]

Which tuner will do that? I'm not running one and have been looking for the right one.

You’ll need to run efilive with those SACs.