M5R2 Rebuild nightmare

J

JT15601

Registered User
Ok so I went ahead and rebuilt my M5R2 because the thing just sucked too bad to explain. So I did all new synchros and bearings and rebuild the shifter and did the fluid upgrade with full synthetic and friction modifier. Well it decided to kick the bucket one day when I tried to shift into 4th at high rpm. Grinded to pieces and had to drive home in first. Turns out I forgot the little needle bearing on the inside of the pilot shaft where it meets the other shaft (yeah yeah noob mistake) so I swallowed my pride because I'm an idiot and replaced the synchro for 4th and went over the whole thing cleaning it all new fluid and all that and made sure it was perfect. Well now 3rd gear grinds when you shift at high rpm/speed. All the other gears are fine. Even if you double clutch or rev match it still grinds if you shift into third going 50mph+ whether up or down shifting. I really don't want to take it out again like what could it be because the synchro is brand new? The only other thing is i shimmed the shifter a little to make it tighter after I blew it out could that affect it? I'm at such a loss. How could I blow 3rd gear synchro in like 2 days?
 
JT15601 said:
Ok so I went ahead and rebuilt my M5R2 because the thing just sucked too bad to explain. So I did all new synchros and bearings and rebuild the shifter and did the fluid upgrade with full synthetic and friction modifier. Well it decided to kick the bucket one day when I tried to shift into 4th at high rpm. Grinded to pieces and had to drive home in first. Turns out I forgot the little needle bearing on the inside of the pilot shaft where it meets the other shaft (yeah yeah noob mistake) so I swallowed my pride because I'm an idiot and replaced the synchro for 4th and went over the whole thing cleaning it all new fluid and all that and made sure it was perfect. Well now 3rd gear grinds when you shift at high rpm/speed. All the other gears are fine. Even if you double clutch or rev match it still grinds if you shift into third going 50mph+ whether up or down shifting. I really don't want to take it out again like what could it be because the synchro is brand new? The only other thing is i shimmed the shifter a little to make it tighter after I blew it out could that affect it? I'm at such a loss. How could I blow 3rd gear synchro in like 2 days?
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Ive got a whole main shaft assembly with all the gears if you are in need for 50 bucks plus shipping
 
Use friction modifier only if you use the penzoil syncromesh fluid. If you use the GM brand syncromesh you don't need friction modifier
 
He is having a syncro problem, syncros need friction to do there job. Why would you add friction modifier who's job is to reduce friction.
 
I just had my late model trans rebuilt and third grinds just like yours is. initially I put friction modifier in it and that's what I think may be hindering its performance. I drained the old fluid out and put new in w out it and it has gotten better but it still grinds.
 
are yall using fiber lined, brass, or carbon fiber blocker rings?

Did you cut off every other tooth?

Did you check the synchro out really well for any wear?

Where r yall finding the rear bearing removal tool?
If anyone has one for sale or knows where I can score one PM me
 
If you're using the solid brass blockers, they don't like high RPM shifts or very quick shifts either. In fact I've discovered that the M5R2 doesn't like to shift well or very quickly at or above about 6000 or so. I've missed quite a few shifts at 6000 and above while racing and have now dropped my shift points to 5500. It didn't grind, just wouldn't go into gear like the shifter hit a brick wall and it doesn't matter which type blockers I use. All of the bearings are available from cobratransmission.com. I've still got plenty of CF blocker sets available if you want to try them. Don't feel bad about making that mistake. I've installed the 3-4 synchro cluster in backwards twice and had to take it all apart to correct.
 
Mike Puckett said:
If you're using the solid brass blockers, they don't like high RPM shifts or very quick shifts either. In fact I've discovered that the M5R2 doesn't like to shift well or very quickly at or above about 6000 or so. I've missed quite a few shifts at 6000 and above while racing and have now dropped my shift points to 5500. It didn't grind, just wouldn't go into gear like the shifter hit a brick wall and it doesn't matter which type blockers I use. All of the bearings are available from cobratransmission.com. I've still got plenty of CF blocker sets available if you want to try them. Don't feel bad about making that mistake. I've installed the 3-4 synchro cluster in backwards twice and had to take it all apart to correct.
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Well Im currently running brass blockers on 1 2 3 and reverse and fiber on 4 and 5. I didn't change 5 because it was perfect so I left it alone. Like I sed I destroyed 4th so I put one of my old fiber ones that was still good in place and its perfect now. 1st and second are doing fine on the brass blockers I can grab second upwards of 5800 without beating it in. At 5500 it will slip in pretty comfortably. 3rd is my issue now it has a brass ring. I'm going to take it out this weekend and swap another of my old fiber rings in place of it I have one good one left... well it looks good to me. I'll check it out wen I get it all apart and see how well its braking the gear. If that does work how much do you charge for the carbon fiber rings? I've heard a lot of good things about them and I might be in need of at least one if this fails to work out
 
I think it is best to use fiber blockers on 2nd and 3rd. You can get by Ok with brass in 1st and 4th. Years ago when I tried out a set of the brass blockers, I completely trashed the one for 3rd gear and 2nd was on its way out after a half season of racing. 3rd was pretty well mangled and was starting to damage the synchro cluster. I charge $250 for a set of 6, $200 for a set of 4, or $50 ea, and $40 ea for 5th and rev.
 
Mike Puckett said:
I think it is best to use fiber blockers on 2nd and 3rd. You can get by Ok with brass in 1st and 4th. Years ago when I tried out a set of the brass blockers, I completely trashed the one for 3rd gear and 2nd was on its way out after a half season of racing. 3rd was pretty well mangled and was starting to damage the synchro cluster. I charge $250 for a set of 6, $200 for a set of 4, or $50 ea, and $40 ea for 5th and rev.
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ok well after this weekend and I get it all put back together if I do have more problems I'll message you about that
 
Mikes Blocker rings are where its at! The blocker rings I put in that are grinding are the fiber lined blockers from southwest gear. I am in the process of getting another late model trans to have mikes blockers put in it and then I am going to buy another set from him and put them in my current trans. As you know you only want to do this once lol.
 
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