M6 guys... trouble downshifting?
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
M6 guys... trouble downshifting?
Does anyone here have alot of trouble downshifting from 5th to 4th, or 4th to 3rd, or 5th to 3rd? Mine is hard to get into gear, sometimes I have to put what I feel is excessive pressure on it to get it to go. Here's the kicker... this trans was rebuilt by a very reputable builder who happens to be local to me. Anyways, the transmission has about 8K on it. I do not drag race nor do I slam gears, this transmission has led a relatively easy life. I had mobil 1 synthetic in it, today I drained it out and changed it thinking that something different would make it smoother. Nope, problem still persists and when I looked at the fluid that came out, it was a dark purplish brown, and had metallic flakes in it. I am NOT happy right now. I am calling the trans shop on monday to see what they say.
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
Your 1999 C5 has paper blocker rings. Mobil 1 is not good for them. I ran Mobil 1 for 50,000 miles (from about 50,000 miles until 100,000 miles) in my 1998, then it started grinding going into 6th gear. I changed to Amsoil ATD (you can use ATF) and problem stopped imediately. Try Amsoil or regular Dexron III.
Now, if they rebuilt the transmission, they may have replaced paper blocker rings with the carbon fiber ones. Then my suggestion is not valid.
BTW, I have 111,000 miles on my original transmission and it shifts fine.
Now, if they rebuilt the transmission, they may have replaced paper blocker rings with the carbon fiber ones. Then my suggestion is not valid.
BTW, I have 111,000 miles on my original transmission and it shifts fine.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
Your 1999 C5 has paper blocker rings. Mobil 1 is not good for them. I ran Mobil 1 for 50,000 miles (from about 50,000 miles until 100,000 miles) in my 1998, then it started grinding going into 6th gear. I changed to Amsoil ATD (you can use ATF) and problem stopped imediately. Try Amsoil or regular Dexron III.
Now, if they rebuilt the transmission, they may have replaced paper blocker rings with the carbon fiber ones. Then my suggestion is not valid.
BTW, I have 111,000 miles on my original transmission and it shifts fine.
Now, if they rebuilt the transmission, they may have replaced paper blocker rings with the carbon fiber ones. Then my suggestion is not valid.
BTW, I have 111,000 miles on my original transmission and it shifts fine.
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
Well there you go, seems like you have a reason to be pizzed ! But I would not go to them with that attitude, give them a chance to "do right by you" first.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
Regardless of what they do, if this is a problem that requires the trans to be pulled, even if they rebuild the whole thing free of charge, I am already pissed off because its alot of labor on my part to get that thing out of there and then back in, and downtime without my car.
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
Regardless of what they do, if this is a problem that requires the trans to be pulled, even if they rebuild the whole thing free of charge, I am already pissed off because its alot of labor on my part to get that thing out of there and then back in, and downtime without my car.
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
I'm gonna try that before I go ripping the transmission out, however I must say I am very concerned with the color of the transmission fluid that came out of there. It was a dark purplish brown with a really light metallic flake to it. It stays in gear and doesn't pop out, its just notchy shifting (I have a hurst, its expected) but the whole not wanting to downshift thing doesn't sit right with me.
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Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Mike
I seriously doubt a fluid change is going to fix your issue, but, its worth a try. Are you SURE your clutch is dis-engaging properly?? Make sure your getting FULL clutch dis engagement .
BC
I seriously doubt a fluid change is going to fix your issue, but, its worth a try. Are you SURE your clutch is dis-engaging properly?? Make sure your getting FULL clutch dis engagement .
BC
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
Pretty sure... It goes forward through the gears fine, but doesn't like to go down. The prob is intermittent though... sometimes it shifts fine, sometimes it hangs up. I bled my clutch real good about a month before I put it away, and the pedal feels good. The thing that really worries me now is seeing how bad that trans fluid looked. I had cleaner fluid come out of the T56 in my SS with 50K on it that was the original fluid that GM put in there from the factory.
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
Pretty sure... It goes forward through the gears fine, but doesn't like to go down. The prob is intermittent though... sometimes it shifts fine, sometimes it hangs up. I bled my clutch real good about a month before I put it away, and the pedal feels good. The thing that really worries me now is seeing how bad that trans fluid looked. I had cleaner fluid come out of the T56 in my SS with 50K on it that was the original fluid that GM put in there from the factory.
had no idea 
so new aftermaket clutch and new slave with remote bleeder and extra insulated clutch fluid lines going in right now
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Ahhhh,,something is dicked inside the tranny. If your fluid looks that bad, it either wearing badly or you have a serious heat issue or BOTH. Take it back to the shop, tell them your issue, let them drive it and feel the problem and "BITE THE BULLET" and remove it and have them rebuild it, repair it or what ever it takes. Yea,,,,its a pain in the ***** but,,,,,,you wont be satisfied until its correct
Bill
Bill
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
Ahhhh,,something is dicked inside the tranny. If your fluid looks that bad, it either wearing badly or you have a serious heat issue or BOTH. Take it back to the shop, tell them your issue, let them drive it and feel the problem and "BITE THE BULLET" and remove it and have them rebuild it, repair it or what ever it takes. Yea,,,,its a pain in the ***** but,,,,,,you wont be satisfied until its correct
Bill
Bill
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
The other part that pisses me off is this gives me an excuse to mod something while it is apart, and I swore no more mods! Although, honestly, I am having trouble thinking of stuff to do...
Racer
Joined: Dec 2005
Posts: 287
Likes: 2
From: Bay Area California
M6 guys... trouble downshifting?
Is there a possibility that the your shifter assembly needs to be re-aligned especially the pinch bolt for the shift rod that connects to the transmission? No doubt you did this when re-installing the rebuilt transmission but, it is such a simple procedure it may be worth checking prior to removing the transmission again. Just a thought...
A1
A1
Burning Brakes
Joined: May 2007
Posts: 1,078
Likes: 5
From: Denver, North Carolina
I usually give the throttle a little tap with the downshifts to match the RPMs and have no problems with smooth downshifts. Mines a 98 w/ 70k using Amsoil ATF. I agree w/ everyone above, you should...
-Refill w/ Amsoil
-Re-check adjustment of shifter pinch
-Match revs, clutchless style
If it still isn't smooth, make it their problem.
-Refill w/ Amsoil
-Re-check adjustment of shifter pinch
-Match revs, clutchless style
If it still isn't smooth, make it their problem.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
no more mods> that is a good one. Sorry but taking things APART is the reason for more mods.
Ok nuff of the jokes
Is it possible the shifting forks have come loose? I think the first thing I would try is take yorur gear shift leaver out. check that.
When I had some minor shifting problems, turns out the gear lever not the trans.
Good Luck
Thread Starter
Le Mans Master
Joined: Jun 2002
Posts: 8,352
Likes: 103
From: In the pit, trying to love someone.
no more mods> that is a good one. Sorry but taking things APART is the reason for more mods.
Ok nuff of the jokes
Is it possible the shifting forks have come loose? I think the first thing I would try is take yorur gear shift leaver out. check that.
When I had some minor shifting problems, turns out the gear lever not the trans.
Good Luck
I emailed D&D performance (shop that built the trans) and I also emailed a friend of mine who used to work there and now works for Livernois to see what they say. I really hope this is something stupid, I am so not in the mood for this. Unfortunately the color of the fluid tells me it is prob something serious.
Melting Slicks
Joined: Mar 2001
Posts: 2,979
Likes: 281
From: Tulsa OK
I had a similar problem. It wasn't only on downshifts, though. It started out being difficult to get into reverse and first. Then I started having intermittent issues with all the gears. It seemed to get worse when everything got hot. We tried bleeding the clutch and changing the transmission fluid. That didn't help. After talking to RPM, I realized I had a clutch release issue. The funny thing was, I had been running the same clutch for 2 1/2 years. The problems started after getting the 402 installed. We put in an adjustable clutch master cylinder and the problem is solved. I'm sure this had to have shortened the life of my transmission, but it is working fine for now. 