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Thread: Tough shifting when hot

  1. #1
    Senior Member 82DMC12's Avatar
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    Tough shifting when hot

    Many years ago, maybe back in 2001, I replaced my clutch with the Centerforce version and added the stainless braided clutch line. At some point replaced the clutch master and slave, only used GT LMA fluid. My clutch reservoir is full but I must admit it's been years since the last flush.

    Lately I've had to rely on the D since my daily is in the shop, and I'm finding it tough to switch gears the longer I drive (hot engine, middle of the day, mix of city and interstate. Especially going from a higher gear into first when entering traffic. It's like there's a lot of resistance I have to push through which sometimes results in grinding. When the car is hot it's almost impossible to get into reverse without grinding so I stop the engine and start it in reverse. 3rd, 4th, 5th, not really an issue at any time. Double pumping the clutch doesn't always help.

    Thinking all I need is a good flush. Right? Pedal feels great and not spongy but I'm not sure what else it could be.
    Andy Lien

    VIN 11596 Jan 1982 build - owned since Nov. 2000!
    Total frame-off restoration completed 2021-2023

    Photography and Backpacking is life.

    Was Fargo, ND
    Now Kansas City

  2. #2
    Senior Member DMC5180's Avatar
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    You’ve certainly done the recommended parts replacement.

    A couple things come to mind as possible causes.

    1. You have low fluid or some Air in the slave cylinder. So the first thing to do is bleed/flush the system.

    2. If the slave is leaking, the clutch disc could be contaminated with brake fluid which then mixes with the friction disc dust, turning it too a sticky black goo.

    I’m betting on number 1 though.
    DENNIS

    VIN 5180, Frame 3652, STAGE II​, DM-eng Solid State Solutions (RPM Rly, Dm.Lt.Mod., Fan Fail Mod. , FAN Rly, HS.Rly) , HID headlights, SPAX user since 2009, Eibach springs, M Adj. Rear LCA's, DPNW poly-sway bar kit, DMCEU LCA Stabilizer link kit, DMCMW Illuminated door sills, Aussie Illuminated SS Shifter plate, REAL MOMO EVO Steering wheel, DELOREANA Extended View Side Mirrors w/ Heaters, DELOREANA LED Door Lights.

  3. #3
    Senior Member DMC-81's Avatar
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    Hi,

    Here's a couple things to check:

    1) any leaking from the clutch master or slave ( as Dennis mentioned)
    2) the level of gear oil in the transmission ( also, how long has it been since it was changed?)
    Dana

    1981 DeLorean DMC-12 (5 Speed, Gas Flap, Black Interior, Windshield Antenna, Dark Gray)
    Restored as "mostly correct, but with flaws corrected". Pictures and comments of my restoration are in the albums section on my profile.
    1985 Chevrolet Corvette, Z51, 4+3 manual
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  4. #4
    Not a DeLorean Guru
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    This is an EXACT scenario I ran into with my former 1987 Esprit. Shifting and transmission behaved perfectly fine until the car was warm. Then, the same issues you described. I ultimately discovered that the clutch master cylinder was leaking internally.
    -Mike

    My engine twists my frame.

    1981 DeLorean, Carb LS4 swap completed
    1999 Corvette, cam/headers/intake manifold, 400 rwhp
    2005 Elise, stock
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  5. #5
    Senior Member 82DMC12's Avatar
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    Thanks boys, got the car up on ramps and check the transmission fluid, perfectly clear and up to the top of the fill plug. then I got my next door neighbor to come over and play Clutch monkey while I bled the clutch cylinder with more Castrol GT LMA from a fresh bottle. there were definitely some bubbles in there and the first few inches to come out looked pretty brown.

    I tested it a bit in my garage and driveway, then ran to the store to get gas. So far so good! hopefully not the clutch master cylinder because I did replace that with a stainless sleeved one from Grady a while back. Though I bet that was 15 years ago now...
    Andy Lien

    VIN 11596 Jan 1982 build - owned since Nov. 2000!
    Total frame-off restoration completed 2021-2023

    Photography and Backpacking is life.

    Was Fargo, ND
    Now Kansas City

  6. #6
    Senior Member
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    Some other things to inspect;
    The hose from the reservoir to the master cylinder if it is "sweating".
    Under the carpet driver's side for any sign of brake fluid.
    Any seepage from the slave cylinder.

    Since you have been neglectful about flushing the clutch fluid we can assume you also did not flush the brakes so get some more fluid and do them next. Both systems should be flushed every other year max. Old brake fluid adsorbs moisture from the air reducing it's boiling point and making it corrosive. When it turns to steam the system won't function hydraulically and it isn't designed to function pneumatically. When the fluid becomes corrosive it pits the bores of the cylinders. When the seals pass over the corrosion it tears them and they leak.
    David Teitelbaum

  7. #7
    Senior Member 82DMC12's Avatar
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    Hi David,

    Wise words for sure. Other owners can probably relate, but I've put off some of that maintenance, telling myself "well I need to do some other brake work, maybe I'll do that this winter, not worth flushing it out and then doing it again in a few months..." and then it never happens because you get busy with other stuff. Before long, you turn into the "dreaded PO" yourself!

    Good wake up call on the clutch though. I did change all the antifreeze a couple years ago but I could certainly use a brake flush. Well, I'll do that when I do my other brake work
    Andy Lien

    VIN 11596 Jan 1982 build - owned since Nov. 2000!
    Total frame-off restoration completed 2021-2023

    Photography and Backpacking is life.

    Was Fargo, ND
    Now Kansas City

  8. #8
    Senior Member
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    Keeping up with maintenance is VERY important. It prevents a LOT of avoidable work if you keep the fluids and filters serviced regularly. It is also an opportunity to look at the car and catch anything you find before it becomes an problem. Every year (or 10,000 miles!) the front end should be greased and the whole undercarriage inspected. Anti freeze tested every year and flushed every 5. Battery tested every year and replaced every 5. Tires every 7. Wiper blades inspected every year. Bulbs and tire pressures once a month or before long drives. Brake and clutch fluid every other year. Monitor gas mileage and when you see it is getting low do a tune-up. Fix any problems as they occur so they don't pile up and then you don't know where to start. If you do this the car will be very reliable and rarely get you stuck on the road.
    David Teitelbaum

  9. #9
    Senior Member Jimmyvonviggle's Avatar
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    Quote Originally Posted by David T View Post
    Keeping up with maintenance is VERY important. It prevents a LOT of avoidable work if you keep the fluids and filters serviced regularly. It is also an opportunity to look at the car and catch anything you find before it becomes an problem. Every year (or 10,000 miles!) the front end should be greased and the whole undercarriage inspected. Anti freeze tested every year and flushed every 5. Battery tested every year and replaced every 5. Tires every 7. Wiper blades inspected every year. Bulbs and tire pressures once a month or before long drives. Brake and clutch fluid every other year. Monitor gas mileage and when you see it is getting low do a tune-up. Fix any problems as they occur so they don't pile up and then you don't know where to start. If you do this the car will be very reliable and rarely get you stuck on the road.
    What do you mean by greasing the front end.
    Barry

  10. #10
    Senior Member
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    Upper and lower ball joints both sides, tie rod ends (with a needle or put in grease fittings) silicone spray on all of the bushings, and the angle drive.
    David Teitelbaum

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