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Hard to shift when car is hot. Can I get a trans guru in here?

9K views 62 replies 21 participants last post by  enginjoe 
#1 · (Edited)
Here are the parts I have replaced to remedy and/or counteract the problem, alas the problem still exists.

ACT HDSS clutch
Mopar pivot ball
Rage-Tek shifter bushings
Rage-Tek billet pedal pivot
Maddog solid shifter base bushings
DCR modified TOB fork
DCR billet pushrod
Mopar slave and master cylinder

When the car gets hot, it is a bitch to get into gears at times, 1st and Reverse are virtually impossible. I usually have to shut the car off to put it in Reverse.

When the vehicle is cold, it goes in all gears no problem at all. This tells me the problem is heat related. I have flushed my transmission multiple times to find absolutely NOTHING unusual - No particles, or material at all what-so-ever.

I am at a loss and sick of throwing money at the car.

A point I wanted to make since Ive driven his car and noticed the issue too:

When you try to go into reverse you get locked out and you can feel the car bump itself back a little bit.
 
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#3 ·
Funny you say that.. I was going to purchase the materials and do it, but I figured - My master and slave are less than 2 months old. How soft could a plastic line really get?

I'll observe it after my drive to work tomorrow.

Thanks for the reply!
 
#4 ·
I don't know, I'm sure that clutch makes it more sensitive to heat though.

The previous owner put a heavy duty clutch in my cousins jeep cherokee and it did the same thing, it would get good and hot and the clutch wouldn't disengage at all. New master/slave/and line (looks like the same material as the SRT4 line). He gave up put a stock replacement pressure plate back in and its normal now. The stock line really didn't like that heavy duty clutch.
 
#7 ·
I may just try that then. Like I said, the car shifts perfect when it's cold. I can go into all of the gears no problem. I don't mean cold outside, I mean the components on the vehicle are not up to operating temperature.

As soon as I take a nice drive, (to work for example), and everything gets up to temperature, it's a lost cause trying to get into gears - Especially those with a higher ratio like 1st and Reverse.
 
#10 ·
Like they said, stainless clutch line and be sure to run some good DOT4+ fluid.

Also if you have not done it try adjusting the crossover adjustment when everything is at opporating temperature... I know it sounds stupid but just try it.
 
#11 ·
Yep, I was almost a non-believer in the stainless clutch line, but at this point I can't think of anything else it could be, given the circumstances of when the problem occurs.

I have adjusted the crossover while at operating temperature a few times, not a stupid suggestion at all.

Thanks for the reply!
 
#15 ·
Added that to the first post! You can certainly feel that it wants to go into gear.

Did u get a new pressure plate along with the clutch? This might sound stupid but I seen it on a locals car with an act Hdss clutch. Shifted like butter when cold but impossible when hot. I had tried many basics before that such as cable and pedal adjustments ect. His tob fork was also new prior. New pressure plate sealed the deal.


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Yep, brand spanking new kit from ACT.
 
#14 · (Edited)
Did u get a new pressure plate along with the clutch? This might sound stupid but I seen it on a locals car with an act Hdss clutch. Shifted like butter when cold but impossible when hot. I had tried many basics before that such as cable and pedal adjustments ect. His tob fork was also new prior. New pressure plate sealed the deal.


Sent from my iPhone using AutoGuide.com App
 
#16 ·
almost sounds like the disk isnt fully disengauging from the flywheel/pressure plate. Look inside the trans viewing port and move the TOBF up and down with your hand. If it moves freely and you you a clanking sound its quite possible the input shaft sleeve bearing is broken... Ive broken 2 of those fkn things... and I have no idea how I did it...
 
#19 ·
I've checked in there with a mechanics mirror and a flashlight before and I had a friend actuate the clutch, everything looked 100% normal!

Its not broken.

Ive broken one myself and know how it feels. His car shifts GREAT any other time except for reverse when warm. And its random. Sometimes it will go right in, sometimes it will lock you out and you can feel the car rock as you attempt to get it in gear.
Yep! If you're moving it's awesome, if you're stopped, you're F^*&ed. Lol

That's exactly what my car was doing two summers ago. The hotter it was out side the worse it was. When I tried to shove the shifter in gear the car would start moving as if I wasn't pressing the clutch pedal at all. I did the SS line and never had the problem again.
Sounds like that may be my problem! I just don't know why it happens on some cars and not others, it makes no sense.
 
#18 ·
That's exactly what my car was doing two summers ago. The hotter it was out side the worse it was. When I tried to shove the shifter in gear the car would start moving as if I wasn't pressing the clutch pedal at all. I did the SS line and never had the problem again.
 
#22 · (Edited)
I wouldnt say broken, just worn out from not being aligned correctly.

Put the car up on jacks stands and put the car in gear then turn the car on, tires probably wont move but u might hear a whining sound from the trans.



http://www.srtforums.com/forums/showthread.php?t=635108

Trans gurus chime in*
 
#24 ·
#30 · (Edited)
My car does the exact same thing. Used to do it on hot days when I drove it to work more often. Now Ive only noticed it after a lot of runs at the track. When it starts to do it for me I adjust the clutch peddle so that it pushes the master cylinder push rod in a hair further. Fixes the issue for me. I agree it's probably the factory hydraulic lines. I've meant to install the SS line but haven't done it yet. IMO the clutch is not fully disengaged because the hydraulic system isn't pushing the fork far enough. You may have seen it move but did it move enough to disengage the clutch? When this issue happens to me the car pulls forward when I have the clutch peddle to the floor with the car in gear. When I adjust the peddle to push in further the issue goes away. I also have a HDSS but I used a stock fork (regret that decision). It may have something to do with the extra load required to disengage the aftermarket clutch wearing my stock fork at an abnormally fast rate?

I only drive my car about 4k miles a year so the issue might come up once a year. I'm curious to see what solves this issue.
 
#34 ·
It definitely moves enough to disengage the clutch because other gears are fine to get into, and it doesn't give me trouble when cold. Only when up to temperature.

I'm thinking the stock lines + heat + heavy clutch = No bueno

Seems to be a hit or miss, some cars are affected, others aren't.
 
#36 ·
I had an HD pressure plate with stock lines until the motor went at 103k miles. Never had that problem. When I did the re-build, I did the SS lines with a new master just in case though because I went with an XT pressure plate. It wouldn't hurt to put it in and it is pretty inexpensive and easy.
 
#38 ·
My 2¢:

1.) DEFINITELY put the SS hose on- you can take ANY late model crotchrocket w/stock front brake lines & do some panic stops. Switch over to SS & cut MANY feet off your stopping distance, that = LIFE -vs- DEATH!
2.) We know that everything expands as it heats up, all of those heated parts have grown a few thou, added up, equals further travel for sufficient clutch release. Many mechanical workarounds. AFTER switching to AMSOIL Synthetic trans oil, see Challenger 6-speed fixes for that AND the svc bulletin RE: molybdenum grease needed on input shaft splines bulletin being performed under wnty on those cars. One mechanical fix would be to drill a new hole in the pedal to give more travel to the slave. Another may be to use a master with a larger piston, perhaps a Challenger master? I haven't been into any of these, but also see to it that NOTHING can flex & reduce travel. If it's possible to get an eye or feeler gauge in there while hot, there should be a bit of clearance between the t/o brg w/clutch out & some clearance between the disc & flywheel w/clutch in. Maybe snake a borescope in there to look. Another item that MUST be taken into consideration is whether or not the bellhousing fits PERFECTLY, with the mainshaft entering the pilot bearing dead center. Chrysler engineering has put out some crap since the Chinese got their fingers in there & their beancounters are always trying to save a penny. Witness the loss of ALL NASCAR involvement on the heels of an OUTSTANDING season for Dodge. Those race engines & pieces are selling for pennies on the dollar now. 850-900HP for $10k or less. Hope I didn't do too mny typos, I can't scroll back on this tiny Android on screen keyboard without losing the cursor, permanently. One other option to add, since you DO reach racing temps, is to add SS hoses to the fill & drain plugs, an oil cooler, & an oil pump to circulate the trans oil. Maybe wire up a temp gauge first to legitimize the added expense. Which adds another dilemma, what IS generating the most heat? All three systems are bolted together & become one big heatsink, so a hot hot engine will end up heating up the clutch, more likely that than the trans heat. Between the SS slave hose, possible dry splines causing the disc to hang, & keeping the entire assembly cooler, this problem should be solved. Assuming there's no casting, machining, or other design or manufacturing flaws in the clutch system & parts used. This type of problem is known to virtually all lifetime motorcycle racers, before hydraulics we could ALL be seen dialing our handlebar clutch cable adjusters many times during races. Whether you gained slack or it got tight depended upon the clutch release design, pushrod -vs- lifter.
 
#43 ·
Awesome post! I don't know if you could find a master with a larger piston, I think it would be trial and error, for sure. Also whether or not it would help would be within question. I will be doing the SS line for sure as soon as I find time in my busy schedule.

If I had to guess, I'm thinking it's just heat generated from the engine, it's basically a giant sauna under the hood. Oh the joys of hydraulic systems!

Had a similar issue on my dads 03 PT. I replaced the slave and still the same issue. Check where the clutch pedal pivot bolt is located. you may have to loosen it and pull the pedal back toward the driver seat. Did that and the problem went away.
There is enough throw, I know that. The DCR rod, by nature, is longer than the stock one, so I have no worries as far as that is concerned.

That would help for a worn fork, not so much in this case, especially since this seems to be a problem with temperature.

When its warm and won't go into first, pump the clutch pedal hard 10+ times rapidly from top to bottom and see if it goes in.
I have tried this with no success.

^ Its random.

Sometimes it will go in like a charm, Sometimes it gets completely locked out. Even if you pump the pedal.
Yep. Dan has seen it, the car needs to be shut off to be put in reverse.

Has the slave been bleed?
It's a brand new MOPAR slave and master. I know it is pre-bled, but I did bleed it before installing. It's bled, that I am 110% sure of.
 
#40 ·
When its warm and won't go into first, pump the clutch pedal hard 10+ times rapidly from top to bottom and see if it goes in.
 
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