Why hard stick shifting when hot?

[friendly_jacek]

My friend has a new (to him) Saturn that works fine when cold first thing in the morning and now in colder weather, but was a bear to shift into 1st gear during last summer but only when engine was hot.

I simply don't understand how ambient temp difference would change how clutch or tranny works.

BTW, he replaced the tranny fluid to make sure the proper fluid is used.

 

[Lead Shoes]

I use GM synchromesh friction modified in my transmissions, my rebuilt carbon synchro ITR trans shifts like pure butter regardless of temp.

On the other hand my Integra shifts like total [censored] when its cold outside, I have tried Amsoil MTF, GM synchromesh FM, Honda MTF, Pennzoil synchromesh. At temps below 40-50 it is odd feeling until you really warm the car up with a good 10+ mile hwy drive. I think its the Orig 270k mile transmission though so the scrapes and rough gears when cold are just a sign that it is worn.

I have only driven one Saturn sc2 manual, it was like punching gears it was so stiff and numb, I really didn't like it at all.

 

[bvance554]

You say its hard to shift into first. Are you completely stopped? Its hard to shift any manual into first if you're moving. Just a thought.

 

[Barkleymut]

You may want to adjust the clutch cable....I know mine needs to be adjusted because when I push it as hard as I can to the floor it shifts fine. If I just push it 95% of the way down it is hard to shift.

 

[eljefino]

Hydraulic clutch in these.

I suspect the synchros are shot in first, and the viscosity of cold trans fluid helps.

Although you'd think the clutch would be completely disengaged with the pedal to the floor, there's still some very slight drag.

I would try a symphony of rev matching and double clutching to make this work. Also do a "good stomp" of the clutch pedal then wait a second or two before trying for first gear so various things in the tranny can spin down.

 

[INDYMAC]

It sounds like a clutch issue to me. Is there air in the fluid. When was the last time it was changed? Clutch might also need adjusted.

 

[eljefino]

The hydraulics are sealed and self-adjusting.

The only option for clutch action improvement is an entirely new master + slave cylinder kit that come pre-connected with a folded hose.

My 95 SW1 suffers an extremely similar condition and new hydraulics did not help. I was lucky and found a hydraulic kit for $40; they are normally $200.

 

[demarpaint]

As already mentioned it could be a few things, I'd start with the cheapest first. Try bleeding the clutch and allow all the old fluid to be replaced with new fresh fluid. I'm always amazed at the results I get when I do that to my van. If that doesn't work the other possible causes have already been mentioned.

 

[friendly_jacek]

Originally Posted By: bvance554
You say its hard to shift into first. Are you completely stopped? Its hard to shift any manual into first if you're moving. Just a thought.


No, it's not that. He drove manual transmission cars for over several years now and he is a very good driver with great technique.

 

[friendly_jacek]

Originally Posted By: eljefino
Hydraulic clutch in these.

I suspect the synchros are shot in first, and the viscosity of cold trans fluid helps.


Yap, hydraulic and it makes things more complicated.

Now, are you saying thicker fluid, say motor oil, should help?

 

[friendly_jacek]

Originally Posted By: demarpaint
As already mentioned it could be a few things, I'd start with the cheapest first. Try bleeding the clutch and allow all the old fluid to be replaced with new fresh fluid. I'm always amazed at the results I get when I do that to my van. If that doesn't work the other possible causes have already been mentioned.


From my understanding, there is no bleeding screw in those and bleeding can be only accomplished by a mityvac pump. I told him to do it, but he put it on a back burner as the shifting improved with colder weather.

My interest now is more why and less how to fix it.

 

[friendly_jacek]

Originally Posted By: eljefino

My 95 SW1 suffers an extremely similar condition and new hydraulics did not help.


Interesting! Do you also have the easier to shift when cold condition? My friend did notice that hydraulics looked brand new. Clutch was also replaced recently. Possibly PO was stumped and gave up in the mid of the summer.

 

[eljefino]

Hard saying. All I know is the car is "moody". I've had other "moody" saturns too in this same way, including one with a brand new clutch. There is a test port (tiny hole) at the slave cylinder where one can stick a paper clip in to the clutch release fork and measure how much it moves. IIRC it needs to move at minimum 13mm-- look it up on saturnfans.

Try jacking it up, put it in first, push the clutch into the carpet, and start it up.

If the clutch has some drag, a tire will spin.

Then we can all argue about if that clutch drag is normal.

 

[friendly_jacek]

Originally Posted By: friendly_jacek
Originally Posted By: eljefino
Hydraulic clutch in these.

I suspect the synchros are shot in first, and the viscosity of cold trans fluid helps.


Yap, hydraulic and it makes things more complicated.

Now, are you saying thicker fluid, say motor oil, should help?


There maybe some merits in this. I found one (but only one) post showing great improvement with Redline MTL that is 75W80 gear fluid: http://www.saturnfans.com/forums/showthread.php?t=5313

BTW, why would you need synchros in 1st when you shift into first while stopped?

 

[MolaKule]

Are you certain the transmission has a synchronized first gear?

Some don't!

 

[friendly_jacek]

Originally Posted By: MolaKule
Are you certain the transmission has a synchronized first gear?

Some don't!


Again, how does it matter if one shifts onto 1st when stopped?