Please Help: Difficulty shifting into gear
Thread Starter
Cruising
Joined: Nov 2013
Posts: 10
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From: Pennsylvania
Please Help: Difficulty shifting into gear
Hello all, I’m a new Corvette owner and I apologize for bothering everyone with a question as a first post. I recently purchased a 1992 Corvette with the LT1 Six Speed drivetrain. The car has about 120K miles on it and it is very difficult to put into 1st or 2nd gear. It acts as though the clutch isn’t fully engaged. It shifts into the other gears without difficulty. After driving the car for a couple hundred miles It went from difficult to impossible to put into any gear, pressing the clutch down didn’t seem to do anything. So I added some brake fluid into the clutch master cylinder and it went back to where it was before, difficult to put into first and second and normal through the rest of the gears. In order to put the car into first or second you have to pull the shifter rather hard toward the driver’s side of the car while putting it into either gear. I was wondering if this issue could be caused by the clutch master cylinder/slave cylinder or if I’m In for bigger trouble. The person I bought the car from said the clutch was recently replaced and it does seem to grab like new. Once again I apologize for pestering everyone with a question and I would certainly appreciate any help. Thanks! ~Mark
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Replace the slave&master that should do it
worst case scenario is the pilot bushing but doubt it. Just went through this wiht a T56/Fbody slave same symptoms.
If the seal is leaking internally the clutch wont fully disengage making it hard to get in gear.
Externally could do the same thing youll just see a leak thats all.
worst case scenario is the pilot bushing but doubt it. Just went through this wiht a T56/Fbody slave same symptoms.
If the seal is leaking internally the clutch wont fully disengage making it hard to get in gear.
Externally could do the same thing youll just see a leak thats all.
Thread Starter
Cruising
Joined: Nov 2013
Posts: 10
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From: Pennsylvania
I sure appreciate the advice. The snow is starting to fly around here now so I'll probably wait until spring to swap out the clutch master/slave cylinder but now I wont worry about it over the winter lol. I was just really concerned it might be something more serious. Thanks again! ~Mark
Thread Starter
Cruising
Joined: Nov 2013
Posts: 10
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From: Pennsylvania
Thanks so much to everyone for the great advice! I won't drive it before I put in the new clutch master&slave cylinder. I was planning on changing the transmission oil as well and in doing a bit of research it appears there are differing opinions on what the best oil to use is. I work at a NAPA and we sell Royal Purple synchromesh. I went on RP's website and it does list it as a substitute for the GM Part#12345349 so I was thinking of going with it. I was also thinking of trying to "Flush it out" if that's at all possible. I was thinking of running diesel fuel or marvel mystery oil in it just to run it through the gears then drain it and fill it with the RP. Is this a horrible idea? lol. I've been pricing out trannys online and I'm really hoping to do something to bring this one back to life lol. Once again thanks to everyone for all the help I sure appreciate it. ~Mark
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The ZF6 should not need any sort of "flushing". If you are going to drin the pold fluid out, simply add the proper fluid for the trans. The GM fluid works as does the Castrol 10W60 sold at BMW dealers. Also consider the Amsoil Synthetic Syncromesh fluid. Some like this particular oil, some don't.
One thing with lighter weight oils (R-P 5W30 and such) is that you may get an increase in noise from the trans.
Might want to look at this page from the ZFDoc website
Also, lots of good information in this thread
One thing with lighter weight oils (R-P 5W30 and such) is that you may get an increase in noise from the trans.
Might want to look at this page from the ZFDoc website
Also, lots of good information in this thread
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Drifting
Joined: Sep 2012
Posts: 1,315
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From: Richmond Virginia
This should solve your problem;
Just kidding. I'd go with replacing your Master and Slave Cylinder. My '93 had a similar issue the first week I had it, and I replaced those and 15,000 later I haven't had the first problem!
Just kidding. I'd go with replacing your Master and Slave Cylinder. My '93 had a similar issue the first week I had it, and I replaced those and 15,000 later I haven't had the first problem!
Team Owner
Joined: Sep 2003
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I'd think the "flush" not a good idea with diesel or Marvel. Marvel if you wanted to would be a better choice but 10W-30 oil a better choice. The GM # 12345349 you mention was never considered a factory fill for the ZF. GM # 1052931 was the factory fill and the RP "suggested recommendation" is HPS 10W-30. You can confirm that at your work or here:
http://royalpurpleconsumer.com/wp-co...ence_Chart.pdf
I believe regardless of the choice of lubricant a regular change frequency is most beneficial to better operation. I've mentioned before maybe every third oil change or maybe every fourth BUT maybe more routinely than most might do.
Resolve your "clash" issue sooner than later and continued use can certainly make it worse. Not mentioned yet is make sure the fill plug is removed before the drain plug. If you can't remove the fill plug and it's drained you certainly have "an issue"!!
An M17 hex for both the drain and fill. If either are in poor condition this VW plug will work well: WHT-001-937 You want that part number only NOT a newer substitute that is "spline drive" unless you're a VW guy with the "spline drive" already.
http://royalpurpleconsumer.com/wp-co...ence_Chart.pdf
I believe regardless of the choice of lubricant a regular change frequency is most beneficial to better operation. I've mentioned before maybe every third oil change or maybe every fourth BUT maybe more routinely than most might do.
Resolve your "clash" issue sooner than later and continued use can certainly make it worse. Not mentioned yet is make sure the fill plug is removed before the drain plug. If you can't remove the fill plug and it's drained you certainly have "an issue"!!
An M17 hex for both the drain and fill. If either are in poor condition this VW plug will work well: WHT-001-937 You want that part number only NOT a newer substitute that is "spline drive" unless you're a VW guy with the "spline drive" already.
Safety Car
Joined: Aug 2013
Posts: 4,429
Likes: 605
From: Minneapolis Mn
Hard getting into gear
I had something similar on my 86, had the master & slave replaced right after purchasing it due to failure. Almost impossible to get into 1st or 2d with the engine running but fine with the engine off.
Try pumping the clutch 4 or 5 times then see if it goes into gear ok or not. If it does then I'd suspect you have air in the system.
Mine did and it was a bear to get out. Found a youtube on how someone had used a hose and fitting in the master to help pull air out, it helped but didn't get it out 100%. Coworked who used to work on GM's suggested pumping the clutch several times, hold about 5 minutes then side slipping the clutch pedal. I did that a couple of times and it got all the air out and it's not been a problem since.
Try pumping the clutch 4 or 5 times then see if it goes into gear ok or not. If it does then I'd suspect you have air in the system.
Mine did and it was a bear to get out. Found a youtube on how someone had used a hose and fitting in the master to help pull air out, it helped but didn't get it out 100%. Coworked who used to work on GM's suggested pumping the clutch several times, hold about 5 minutes then side slipping the clutch pedal. I did that a couple of times and it got all the air out and it's not been a problem since.
Thread Starter
Cruising
Joined: Nov 2013
Posts: 10
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From: Pennsylvania
Thank you so much to everyone for all your help! This forum is wonderful! I got the HPS Royal Purple 10w-30 and a 17mm hex for the oil change. I also bought a new (Remanufactured) clutch master/slave cylinder along with valvoline synthetic dot 3/4 brake fluid. I've abandoned the notion of "flushing" the trans but I bought 5 quarts of the Royal Purple and I plan to change it again after 200 miles or so. I just wish it were spring so I could get everything done and see if this transmission is going to make it LOL. Again I’d like to say thanks a million to everyone for all their help and I’ll be sure to keep you posted as soon as get everything squared away. ~Mark
Advanced
Joined: Nov 2013
Posts: 58
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From: Hidden Valley Lake California
Thank you so much to everyone for all your help! This forum is wonderful! I got the HPS Royal Purple 10w-30 and a 17mm hex for the oil change. I also bought a new (Remanufactured) clutch master/slave cylinder along with valvoline synthetic dot 3/4 brake fluid. I've abandoned the notion of "flushing" the trans but I bought 5 quarts of the Royal Purple and I plan to change it again after 200 miles or so. I just wish it were spring so I could get everything done and see if this transmission is going to make it LOL. Again I’d like to say thanks a million to everyone for all their help and I’ll be sure to keep you posted as soon as get everything squared away. ~Mark
Team Owner
Joined: Sep 2003
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I'd try to locate this original GM clutch fluid for the master/slave. Does it make a difference? I'll say yes but I've never had a "catastrophic" hydraulic failure. You want GM # 12345347 and you shouldn't have any difficulty. You don't want a "replacement" part # if they offer it. It was discontinued but there should be product on dealers shelves.
Don't be so "overjoyed" that you don't post back!!!
Thread Starter
Cruising
Joined: Nov 2013
Posts: 10
Likes: 0
From: Pennsylvania
“as said in an earlier post pump the clutch pedel a few times and see if it is easier, if not it might be your pressure plate, if it is always change the throw out bearing at the same time.”
Pumping the clutch pedal doesn't seem to have any effect. However, when the clutch master cylinder was low it wouldn't go into gear whatsoever and adding fluid allowed me to shift into gear even though it remained difficult to do so.
Regarding the oil analysis my Father works at a laboratory so I'll be sure to ask him if he can do it for me when I dump the oil after 200 miles. I'll be sure to post the results if he is able to do it. Again thanks so much to everyone for all your help. I've been a member of LS1.com for years (I had a Z28) and while those guys are helpful as well I've never received so much good information in such a timely manner. This forum is terrific and I certainly wont forget to post back no matter how overjoyed I get LOL. Thanks again, ~Mark
Pumping the clutch pedal doesn't seem to have any effect. However, when the clutch master cylinder was low it wouldn't go into gear whatsoever and adding fluid allowed me to shift into gear even though it remained difficult to do so.
Regarding the oil analysis my Father works at a laboratory so I'll be sure to ask him if he can do it for me when I dump the oil after 200 miles. I'll be sure to post the results if he is able to do it. Again thanks so much to everyone for all your help. I've been a member of LS1.com for years (I had a Z28) and while those guys are helpful as well I've never received so much good information in such a timely manner. This forum is terrific and I certainly wont forget to post back no matter how overjoyed I get LOL. Thanks again, ~Mark
Thread Starter
Cruising
Joined: Nov 2013
Posts: 10
Likes: 0
From: Pennsylvania
I'd think the "flush" not a good idea with diesel or Marvel. Marvel if you wanted to would be a better choice but 10W-30 oil a better choice. The GM # 12345349 you mention was never considered a factory fill for the ZF. GM # 1052931 was the factory fill and the RP "suggested recommendation" is HPS 10W-30. You can confirm that at your work or here:
http://royalpurpleconsumer.com/wp-co...ence_Chart.pdf
I believe regardless of the choice of lubricant a regular change frequency is most beneficial to better operation. I've mentioned before maybe every third oil change or maybe every fourth BUT maybe more routinely than most might do.
Resolve your "clash" issue sooner than later and continued use can certainly make it worse. Not mentioned yet is make sure the fill plug is removed before the drain plug. If you can't remove the fill plug and it's drained you certainly have "an issue"!!
An M17 hex for both the drain and fill. If either are in poor condition this VW plug will work well: WHT-001-937 You want that part number only NOT a newer substitute that is "spline drive" unless you're a VW guy with the "spline drive" already.
http://royalpurpleconsumer.com/wp-co...ence_Chart.pdf
I believe regardless of the choice of lubricant a regular change frequency is most beneficial to better operation. I've mentioned before maybe every third oil change or maybe every fourth BUT maybe more routinely than most might do.
Resolve your "clash" issue sooner than later and continued use can certainly make it worse. Not mentioned yet is make sure the fill plug is removed before the drain plug. If you can't remove the fill plug and it's drained you certainly have "an issue"!!
An M17 hex for both the drain and fill. If either are in poor condition this VW plug will work well: WHT-001-937 You want that part number only NOT a newer substitute that is "spline drive" unless you're a VW guy with the "spline drive" already.