trans shifting question


New Member
Hope all you tranny guy's can help. i have a 87 gn all orig. no mods. When shes cold 1-2 shift will snap your neck and rip the tires once she warms up the shift is firm but dosnt rip the tires. all other shifts are good tv adjustment is good lock-up seems to be working fine. thanks for the help..
How many miles are on the car and what is the service history on the transmission; ie. fluid & filter changes?
66,000 miles most of them in od on highway serviced every 15,000 miles. im a tech for 19yrs for gm never really got into trannys and the guys at the shop wont touch my car they say im a nut and dont want to deal with me it something goes wrong. im thinging it could be the plates inbetween the valvebody and case were the check ball are when the heatup and expand i have a loss of pressure i have seen this on new t jimmys.... hope this helps
it's possible that

The 1-2 accum spring in the accum housing broke, or that the center check ball in the valve body beat the plate and went thru. Another thing that i just thought of is a sticking 1-2 accum {trim} valve in the valve body. The accum housing is right behind the filter on you lower left side {under the car looking towards the front tires} 3 bolts hold it on just remove the bolts and pull the housing. there should be nothing else other than the spring and the piston.