Transmission shudder

J

Joisey Jim

Guest
My '94 SC (4R70W auto trans) sounds like I am driving over rumble strips when I go WOT, say over 50mph. I had the typical shift shudder years ago and changing over to Mercon V has eliminated that for over 100k now. This is different and doesn't occur when going WOT from a standing start; so I've eliminated balance, U-joint, trans or diff mount problems. It only occurs once it's moved into O/D and presumably the torque converter has locked up. I've totally flushed the fluid but the problem is still there. Could it be a bad relay or is the torque converter on it's last legs.
 
if it shudders going into O/D then the bands are wasted, your transmission will grenade from back to front if you keep driving it that way. If it sudders going out, it could also be a solenoid, but if not then you have to rebuild more than just the O/D.
Been there.

paul
 
Thanks Paul. It doesn't shudder going in or out of OD; I can even put it in/out of OD using the switch and it's quite smooth. In fact I've been taking it out of OD (using the switch) when I want to accellerate hard and doing so eliminates the shudder; then I switch the OD back on around 4500 rpm. So it only shudders when I get on the gas in OD. I wonder if it's the solenoid that should make it kick out of OD?
 
could also be a line pressure problem.
you will know in a relatively short period of time if the bands are worn, it will get worse and happen more often.
if it rumbles when you punch it out of O/D, then the servo/solenoid is not releasing fast enough, or the drive band is applying too soon or just worn.
only thing I dont miss about my 95(4.6) was that transmission:(
is there such a thing as a J MOD for an SC Auto?
 
Someone else had suggested replacing the solenoids & I recall there are only 3. So I may do that before resorting to a trans shop. I bought this car with only 15k and when it started to shudder between shifts,so I took it to a Ford shop where I worked. It was still under warranty and they were going to replace the torque converter. But then I got transfered and went back to my local Ford shop who came up with the latest Ford TSB to just flush the fluid. That did fix the problem and then I read the article on the TCCOA site about the woes of the 4R70W trans; so I did most of the recommended '96 upgrades (solenoids, MLPS, accumulator pistons, bigger sump & filter, Mercon V as well as installing a Transgo shift kit).
I now have 135k and apart from a small fluid leak that drips from the TC housing the trans has been a gem. So I guess I can't complain.
 
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