tdf

My 4-speed will pop out of gear when decelerating in 2nd.

What is the likely part inside the transmission that is causing this?

Thanks

pmihaltian

Could be needed shift linkage adjustment or the need to replace worn syncronizers. Start with the linkage adjustment.

Yellow2015

When you say "pop out" do you mean overdrive or does the 4 speed actually pop out of gear........?

c4cruiser

Popping out of 2nd gear with B-W T-10's is usually worn syncros or somtimes the shifter fork detents or springs can go bad.

Linkage out of adjustment is a common cause. They are not fun to adjust.....

tdf

It's the tranny not the OD Unit that is poping out of gear?

I installed the short shift levers months ago, so I'm familiar with the shifter adjustment routine. I may try reinstalling the stock shifter levers and readjusting to see if that solves this.

I am really not a fan of this GM shifter design!! But I don't think anyone has offered an after market shifter solution. Anyone else know of one??

c4cruiser

The shifter is unique to the Corvette but there have been other 4-speed GM shifters that bolted to the body and not to the tranny like a Jurst shifter does. They were as much as a PITA to deal with in terms of adjustment and binding issues because the engine and tranny were not a solid part of the driveline like the Corvette driveline is.

Because the OD unit makes up the "tailshaft" of the tranny case, there is no place to put mounting holes for as shifter body.

While you are under the car, you might check to see if there is excess wear at the points where the shifter rods attach to the shifter body. Enough slop in the arms and you might not be getting the tranny all the way into 2nd gear.

anchami79

How hard (expensive) is it to have your syncros replaced? Mine has been doing the same thing for a while now. I've tried adjusting the linkage with no luck.

Curveit

If it didn't start until you installed the "short-shift" kit, I'd guess the linkage is out of adjustment. It's a PITA to get right, but much nicer when it is.

DanZ51

The FSM shows a metal tab used to align the shifter mechanism. The tough part is the factory console is completely in the way to use this alignment tab. IIRC, if you pull the cover off the top of the console and look at the bottom of the shifter mechanism you will see at least the 1-2 and 3-4 notches and shifter frame notch (R is the hard one to see, I think). I've managed to "eyeball" the adjustment, after I installed the shorter shift arms.

With the tranny in Neutral the notches should be perfectly aligned together. If it's off, crawl under the car and adjust the offending linkage clevis. Keep track of what you're doing in case you really screw it up (worse case scenario) It doesn't take much to really screw with your shift feel. After doing it once you'll be a pro

all show and more go

and make sure you do it right, i've been left stranded because of binded linkage, funny story: the 4th time this happened to me i had my top off and got so pissed that i stood on top of the seat and started kicking the hell out of the shifter when a cop pulled up to me and asked if i needed assistance, he said he's a ford guy!lol, that calmed me down!

redrose

all forward gears 1/2/3/4 are in constant mesh/position in the main gearcase...to ''engage'' any gear, a ''synchro drum'' with internal ''dogs'' is moved onto drive dogs on that gear, with a brass ''synchro ring'' helping the rotational speeds of the parts match up...the drum,gear, and ring dogs have sharp ''noses'' when new, but abuse and even normal wear destroys the ''noses'' and poor shift action during engagement and ''jumping out of gear'' occur....probly gonna need a new drum and the hub that it slides on (the two are ''select fit''), new 2nd speed gear, and synchro ring -- parts+labor abt a grand

sharkface

Adjustment of Doug Nash 4+3 shifter linkage (1985 C4)
Just wondering,
Now that the driver's seat is out and the left counsel cover off, most of the shifter is exposed. I should say, the neutral adjustment slot is exposed. The trans tunnel is still covering the adjustment nuts at the end of the linkage bars, (toward the front of the car).

Are these adjustment nuts easier to reach by jacking the car up and from underneath? Should the transmission tunnel be removed from the interior of the car to gain access?
There is a cover that needs to be removed before the linkage rod adjustment nuts can be exposed. If it is better to remove the transmission tunnel, what is the best way to do this? Can the linkage bars be adjusted from the rear where they fasten to the actual shifter. It seems odd GM would let you expose the slot for the neutral alignment and not the ability to adjust the rods at this end.

Thanks Again,
Sharkface