Shifts better when cold? Please help!

[theAntihero]

I also posted this isn the tranny forum.

Ive got a m5od thats acting sort of strange. I replaced the master cylinder and was resigned to the fact that the slave wasnt far behind but on a whim i checked the fluid in the tranny.

It was super sludgy and old(this car was recently resurrected for a 7 year slumber of sitting in the woods) so i replaced it and added some Lucas. Now when i first start out it shifts fine but the longer i drive it the harder it is to get into 1st and 2nd and the notchier it shifts.

This doesnt make sense to me, how can the slave cylinder "heal" itself when it sits?

Any ideas?

 

[PanamaExpat]

When you resurrected it did you and installed the master cylinder did you completely replace the fluid in the clutch hydraulics? Are you certain that you have adequately bled the clutch hydraulics? Is it losing hydraulic fluid?

My strange Korean 4X4 was experiencing a similar problem just before she blew the clutch slave cylinder. It was leaking and drawing a small amount of air into the line. Fortunately it is on the outside bolted to the bell housing. But what I suspect causes this is an air bubble in the clutch system and as air gets warmer it expands and becomes less dense. Therefore the pedal doesn't throw the slave as far as it does when the fluids are cold. I think it has something to do with physics.

I would completely change the fluid and bleed the clutch hydraulics first to see if you have any improvement. Pulling the transmission to change out the slave is a drag.

 

[adsm08]

If there is a pinhole leak at the slave driving around will push fluid out and suck air in as you work the clutch. After it sits fluid runs down and pushes the air out the hole, and so it seems to work properly for a while.

A similar condition can be caused by not getting the system fully bled. An air pocket usually gets trapped at the first bend in the line, right at the bottom of the master, which is the issue I currently have, and it does the same thing. Working the clutch works that bubble back and forth and gets it into a spot where it interferes with proper operation.

Also, fluid that is too thick can cause hard/notchy shifting as the trans gets warm (I know, doesn't make a lot of sense, but there was a bulletin about it a while back). Get the Lucas out of the trans and replace it with straight ATF.

I also posted this in the tranny forum.

Finally, don't double post.

 

[pcollins]

I had these same exact symptoms in my '97 ranger. adsm basically nailed it. When I replaced the slave i took the bearing/spring off and found the little pinhole leak that was the cause of a years worth of issues (i was 16 at the time with no $$$ to fix so i drove it like that for over a year xD)

 

[theAntihero]

Its been bled, actually twice because i thought maybe i didnt do it well enough the first time. I actually ran straight atf first then added the Lucas after and it shifted far better with the added Lucas. I plan on changing it again here soon because of how old the original fluid is and im thinking of leaving the Lucas out for the winter months though.

It makes sense about the pinhole leak though, it doesnt leak any fluid though.