Author Topic: mm7 trans r&r  (Read 2228 times)

Offline muleystruck

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mm7 trans r&r
« on: November 17, 2017, 07:18:22 PM »
My 86 Scottsdale has the 4.3 and mm7 trans. I originally thought it had the my6. So now the clutch needs replacing. Ive never pulled this trans before and I'm needing to know if there is anything specific about this job. Ive done clutches with different trans 3 speed Saginaw and an sm465. Don't wanna sound like a goob for asking this cause I may be doing the r&r at a friends shop. Just want to be prepared. Thanks  Muley

Offline zieg85

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Re: mm7 trans r&r
« Reply #1 on: November 17, 2017, 07:38:32 PM »
MM7 is the 4x4 version with a cast iron case while the MY6 is the 2 wheel drive aluminum case is what I have always thought
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline muleystruck

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Re: mm7 trans r&r
« Reply #2 on: November 21, 2017, 05:38:47 PM »
I originally thought the trans was the my6 but I had to r&r  the glovebox insert, saw the spid saying the trans is a mm7. the truck is 2 wd also. So... Not gonna say the spid hasn't been changed at some point. Just going by what I've got. Gonna r&r the clutch this weekend (oh joy!) hopefully so maybe I'll find out for sure. mm7 is 4x4 my6 is 2wd  glad to know this. Thanks!  Muley

Offline zieg85

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Re: mm7 trans r&r
« Reply #3 on: November 21, 2017, 05:59:03 PM »
I originally thought the trans was the my6 but I had to r&r  the glovebox insert, saw the spid saying the trans is a mm7. the truck is 2 wd also. So... Not gonna say the spid hasn't been changed at some point. Just going by what I've got. Gonna r&r the clutch this weekend (oh joy!) hopefully so maybe I'll find out for sure. mm7 is 4x4 my6 is 2wd  glad to know this. Thanks!  Muley
do not know that for sure.  They may have made 2 different RPO's as well.  I actually have a 2 wheel drive version with the standard bolt pattern to the bell housing
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline muleystruck

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Re: mm7 trans r&r
« Reply #4 on: November 25, 2017, 03:17:24 PM »
Well, got the clutch replaced and now the slave cylinder is not right. We didn't break the system so I guess I need to bleed the clutch. The clutch grabs right the floor, was hard to put in gear, and had to pump the pedal several times to shift after driving awhile. So is bleeding the slave cylinder my next task? I ask this because I haven't had much doings with hydraulic clutches. The new clutch works as it should other than this issue. Any help is greatly appreciated as I'm 60 yrs old with physical limitations. (bad knees, arthritis, the usual)

Offline zieg85

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Re: mm7 trans r&r
« Reply #5 on: November 25, 2017, 03:25:26 PM »
Yes bleed the slave.  2 man job.  You can't really pump it like brakes.  Basically have someone down below, open the bleeder push clutch to the floor, tighten bleeder and repeat.  Final bleed is push the clutch in all the way, then crack the bleeder quickly then close it to burp any remaining air.  This is the procedure I use, right or wrong
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline muleystruck

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Re: mm7 trans r&r
« Reply #6 on: November 26, 2017, 09:36:27 AM »
zieg85, I thank you for your reply. Gotta find me a helper now!  Muley