GregWS6&z28

iTrader: (8)

on the interstate one day I lost 4th gear.

-around town driving the trans will only go into 4th under very low TPS and very slow speed.......-will not go into 4th at any high rpms or higher speed.
-not the tune.
-converter locks up.
-car thinks it's in 4th gear (it's commanded) but physically it's not engaged.
-I've put in a new pressure switch
-next guess is that it's the Sonnax 4th gear servo.
-I have a built trans
-any ideas?

performabuilt

iTrader: (25)

Check the servo , Then check the band clearance you should be able to lock down the band by pressing in on the od servo hard. If you cant you may need to tighten band clearance for the 4th servo only.

GregWS6&z28

iTrader: (8)

would this just involve removing the snap ring and pressing in? how would I tighten the clearance? adding washers? being if it is this and it's not grabbing, would that be a sign that maybe the tip of the pin was broke off?

performabuilt

iTrader: (25)

You do not need to remove the snap ring just push in on the servo coverter, And I doubt its the pin but bands do stretch with time andit may be the clearance was borderline at the build time but after the band wore in and stetched it was to much clearance and yes you can use thin washers to tighten it up similar to the gold one used with the sonax servo allready,

GregWS6&z28

iTrader: (8)

ok that sounds good. I didnt think the cover would push in with the snap ring in place. I just took out and replaced a servo on an old transmission I have and with the new seal it was tight and the cover wouldnt push in at all.

performabuilt

iTrader: (25)

its hard to push , but thats the only way I know to check it from the outside with pan on it should prevent the driveshaft from turning one way but it will turn the other way of course the car must be in neutral raised

GregWS6&z28

iTrader: (8)

I'll see what I can do checking it. I may hve another servo on the way to try. THanks for the helP!!

GregWS6&z28

iTrader: (8)

i've been tuning (with some help) since my cam. I've opened the TPS up about 3% (still well within range of 4% that problems start arising). Can the TPS be causing problems with the 4th shift? all other gears are fine. once I opened the throttle blade for the cam I reset TPS to 0%. It's just funny that it took almost 180 miles of driving and after a WOT blast on the interstate for this to have happened.