90&91max

Hey Guys, I need your help on my 91 auto.!
My 91 Shifts in and out of overdrive(rapidly back and forth) while on a slight grade. I can let off the gas or give it a little more and it will stop for a little while. Some days it wont act up at all. I've tried the moving the trans selector from normal to comfort to performance but it still does it. The transmission had been changed once upon a time. Previous owner said its always done it. its not right! My 90 didnt do it. I still have my 90 for parts if I need to swich any out. I just dont know anything to swap!
Could it be the throttle position sensor? Which wires is the pinouts? Voltage?
Trans selector linkage?
I can disengage the overdrive and the trans works great, but milage sucks!
Fluid was changed a few thousand mile ago!
Thanks for any info!
I'll check back in a little while for any responses.
90&91 Max

maximagxe90

Hi,

my be you want to wiggle the cable a little bit in the shifter area so the o/d doesn't do that,

the cable for the o/d is in the right hand side of the shifter box but in a tight spot,

hope this help,

Matt93SE

iTrader: (44)

is it full of fluid?

honestly, something like this is *usually* best left up to a tranny shop to fix. sometimes it's a loose connection on the tranny, sometimes it's a bad shift solenoid, sometimes it's high fluid pressure...

how hard are the shifts between gears under normal driving?
if they're very hard and quick, you might want to check the dropping resistor connection too. there's a small vacuum canister on the driver's side strut tower... there's a wire connector on it, running to a metal bracket under the air filter box area and says JECS on it... that's your dropping resistor. if that's disconnected or damaged, it will cause the tranny to run at full line pressure all the time and will eventually kill the transmission. I noticed it doing symptoms similar to what you're talking about, but only at speeds of 80+.

90&91max

Yes it is full of fluid.
Sometimes it shifts so hard it feels like it would chirp the tires!
However most of the time it shifts perfect.
I'll try swapping the cannister with my 90.
Thanks for the info!
I'll let you know if it works!!

Matt93SE

iTrader: (44)

it's not the canister- I was just using it for a point of reference. there's an electrical connector on the side of the connector- just where it's mounted in the engine.
there's a wire running to a grey metal "thing" under the air filter box area.
check that guy.