Help transmission problem
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Help transmission problem What would cause weak reverse and weak when I put in drive but drop it to 3 and shifts fine then you shift up to drive going down the road and goes into drive fine but then stop and have to drop to third again to take off? Everything in transmission is new except pump could it be a week pump or bad booster valve? Thank you in advance for any help
If it wont move after stopping in the OD position I would have to guess an issue with the input sprag and or the forward clutch when you place it in d3 you turn on the overrun clutch bypassing this .
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From: Ann Arbor, MI
Frank, unless I'm missing something, the overrun clutch is only applied for 3rd gear in D3; I'm sure you know the ATSG manual is wrong about the overrun being applied in 1st and 2nd in D3.
The usual symptom of a bad input sprag is that the driver has to manual shift to D1 or D2 before the car moves and then manually shift up when the speed is high enough.
Carboy: I wish your explanation was clearer because it seems that Frank and I are reading it differently. I strongly suggest connecting a pressure gauge to your trans and checking the values in Park, Reverse and Drive. A trans shop can easily do this or you can buy your own on Amazon for $40 (ATD-5550).
The way I read your short description, I do think it is a low pressure problem, possibly due to a bad pump.
However have your absolutely confirmed that the fluid level is high enough?
The usual symptom of a bad input sprag is that the driver has to manual shift to D1 or D2 before the car moves and then manually shift up when the speed is high enough.
Carboy: I wish your explanation was clearer because it seems that Frank and I are reading it differently. I strongly suggest connecting a pressure gauge to your trans and checking the values in Park, Reverse and Drive. A trans shop can easily do this or you can buy your own on Amazon for $40 (ATD-5550).
The way I read your short description, I do think it is a low pressure problem, possibly due to a bad pump.
However have your absolutely confirmed that the fluid level is high enough?
My understanding is it is applied in 1st and 3rd but off in second in D3 and this is also what the GM tech manual shows and of course with the Sonnax HD 2-3 valve installed is on in 1-2-3 in D3 But I will double check this .
Of course on the poster post knowing more about the rebuild would help also .
Of course on the poster post knowing more about the rebuild would help also .
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