drewz06

hey all,

I was heading home the other day, got off the highway, slowed for the intersection.

car was at normal temps and shifting had been smooth like butter since I got it (used, cpo, 50k miles)

light turns green and I moved to shift into first and it resists a little, as if it was the first time I shifted after a cold start.

no grinding or noise as I accelerate, shift to two and same sort of feeling but engages without grinding etc...

3 and 4 are fine....

I drive less than a mile to the house and think that's odd.. so I go to put into reverse and it feels similar to if you tried to engage a gear without the clutch in...

I didn't force it, but it wouldn't go...

I did some research and tried shifting to first, let a little clutch out, then try for reverse again and it won't let me in.

it allows me past the reverse lock out and over into the reverse gate, but as I moved the shifter forward to engage it fights.

I was able to roll back in the driveway and it engages but not easily... I reversed for some distance and the gear is fine, no problem when engaged...

anyhoo, I got a vehicle protection plan and had them pick up the car yesterday... they are taking it to the dealership I purchased it from.

so, from what I've read there's actually a reverse synchro that may have gone bad? but why would 1/2 be fighting me? bent shifter forks? maybe linkage?

Fly N Low

My guess is you have a clutch issue. There are many posts about clutch master and slave cylinder problems. On some years there is a TSB out for these same problems. Also when the clutch fluid gets really dirty it can plug up the clutch hydraulic system and cause the same problem. Search the "Ranger Method" for cleaning up the hydraulic system.
Anyway It sounds like the clutch is not fully disengaging.

gliot1

I just did the Ranger method last weekend on mine.....yes there was quite a bit of sludge and the fluid was brownish cloudy. Now it is clear and light yellow as it should be. I think I will watch this closely now and do the flush regularly as it was very easy to do!

schpenxel

Clutch isn't disengaging fully. Likely master or slave issue.

drewz06

Thanks everyone!

The dealer called me telling me the "transmission" guy said theres probably something wrong with the clutch..

After research and advice above, i'm going to bet that the hydraulic clutch system is likely where the problem is.

I'm going to try to flush the fluid a few times to see if it improves, ordered an oem master cylinder just in case...

Will keep everyone posted as to what happens!


found that btw, good stuff!

-drew

drewz06

just a follow up...

replaced master clutch cylinder with new oem from tick...

helped when cold, shifting was back to normal "butter" feeling, no resistance when shifting...

drive in to work feels fine at rush hour until I'm almost to work.

when I get to work I have trouble getting in to reverse and all gears are catching synchro teeth... one or two "clicks" when moving to the next gear...

I'm going to change the trans fluid today with AC Delco oem mineral oil to see if that helps.

88861800 is the part number

Fly N Low

Do you think you might still have some air in the clutch hydraulic system?
The way GM designed this system you cant get to bleeder however if you ever pull the trans make sure you put Ticks remote bleeder hose on.
Sounds like it worked for a while then started failing again so maybe air?

drewz06

so i've opted to follow the GM service manual to perform a proper clutch bleed after installing the new master...

i had a hard time fighting the fittings together while adding the clip and i think some air may have gotten in the lines after the new master....

the manual instructs (roughly):

1. lift car in air
2. unbolt catalytic converters
3. disconnect H pipe and remove
4. remove propeller shaft tunnel plate
5. bleed clutch from bellhousing
5a. assistant depresses clutch pedal fully to floor
5b. while holding pedal down, open bleed.
5c. while pedal down, close bleed once sufficient amount has evacuated

so i have performed 1-4 mostly.... attaching pictures.

my process:
a. lift car / remove drivers wheel
b. unbolt brake line support from frame
c. remove sensor plug/wire from frame
d. unbolt drivers side catalytic converter - no need to remove, just drop it down
e. disconnect H pipe from cats (not from the axle back)
f. unbolted tunnel plate and slid towards rear of car

this allowed me to get a shorty wrench into the area without much more trouble.

i didn't have enough time last night to wrap it up, going to attempt after work today.

it's not all that difficult of a process, GM could have put the bleed valve on the other side of the slave inlet pipe to make everyone's life easier though...

drewz06

follow-up!

so i was able to bleed as per GM service manual....

i had to drop the "spring hanger" nuts and let the H pipe drop down in order to get to the bleeder screw...

it's a 9mm you'll probably want a 3 or 4 inch wrench with a closed head...

i needed to lay with my head "under the drivers front wheel" and my feet under the "passenger front wheel" to get the right angle for both my hands to get in the small area...

i needed my left hand to guide the closed end of the wrench and my right hand to loosen the bleed screw..

the fluid just drips right on your chest and i didn't care much to find a way to catch it other than a fender cover over me....

you have to "kind of loosen the screw, then adjust wrench, then loosen fully" so that the fluid is able to escape.

you will hear the sound of fluid moving through a tube as the screw opens enough to bleed.

the key here is to keep the clutch pedal pressed to the floor as you loosen and then tighten after the bleed.

once the bleed screw has been tightened, the pedal will stay on the floor.

you will need to "pull" the clutch pedal off the floor and then pump a few times to get "the normal feeling" back. (this draws clean fluid from the master cylinder reservoir into the slave cylinder)

we could bleed twice before the reservoir needed to be refilled.

after approx 9 "bleeds" we were seeing clear fluid.

this has essentially fixed my shifting problem.

reverse still fights me some.....

however.... when i was bolting up the exhaust, i noticed on the transmission a sensor above the fluid fill port that appeared to have trans fluid on it that was "fresh".

i have the GM fluid to swap, but i will have to find the sensor and replace.

i have attached 2 pictures of the bleed screw location, this is looking forward from the rear end.


i am fairly sure the ranger method is effective if you do a GM bleed then keep it clean with ranger...

i got mine with 50k miles and im sure the clutch fluid was never changed. it was black the first bleed.

i will update after i do the trans fluid change, i would bet at this point that the low fluid is what is causing the last bit of resistance when shifting to neutral. (err... i mean reverse... beer yay!)



oh.. also... after doing the bleeding like this, be sure to hose everything down with brake clean....

there will be a "isht ton" of fluid that comes out of the bell housing ports...

joliett

Great write up and pictures...thank you so much for posting your excellent procedures. You did a great job...now I wonder if I should tackle this job myself.....ughh!!!

Spaceme1117

There is another thing you can check. Sometimes the shifter linkage at the shifter box can loosen up over time. There is a procedure you can follow to get it properly aligned while you tighten it up.

Right after I had purchased a used C5Z my shifter linkage loosened up. Was having a lot of trouble getting into gear and especially reverse. Thought my transmission was going bad at first. Simple alignment and re-tightened linkage and perfectly fine.