On my m1008 with 6.2 and th400 and 4.56 gears, if im on the gas hard it will shift pretty hard into 2nd, I can chrip tires, this isnt normal is it? Also it only stays in 2nd for like 3-4seconds, but i think thats b/c of the 4.56s. Any ideas?
CK5
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th400 shifting hard into 2nd?
- Thread starter protechk5
- Start date
My '90 with the 5.7l gas and TH400 does hits 2nd hard also. I kind of like it.
protechk5 said:
TH400's are weird; they do shift by vacuum (which is even weirder on diesels) ... but the kickdown is electric and is notoriously unreliable on our trucks. They're also not adjustable. Well, they're not made to be.
You might look on your gas pedal (err, accelerator
) and see if there's a piece of fuel line zip-tied around it, as that would kick the kickdown earlier 
Alternately, could be an adjustable vacuum modulator, or could just be the way it works ... my CUCV is an '09, so it has 3.08:1's and ... well, it won't chirp sh!t
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protechk5 said:
I don't think that is normal, mine shifts smooth and I have 4.10 gears and 29" tires, you can feel it but it doesn't jerk or chirp, you just feel the a slight push.
Maybe you are low on fluids, or the vacuum actuator is bad or you have a leak in the vacuum lines.
I know when I had a leak in the vacuum it would shift late and hard like that.
