Harsh downshifting

Dozerboy

Well-known member
Jun 23, 2009
4,406
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TX of course
I through some in my truck today since my truck has always had some hard down shifts. Even when stock. They are where really bad when I was doing some spirit driving to the snow several weeks ago. Drove my truck today and didn't have any hard down shift. Whish I knew about this years ago.
 

OleBlackyLBZ

Active member
May 22, 2020
154
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28
Well my crank broke about 150 miles after I poured it in so DON"T DO IT!🙈 Nah, best I could tell it helped mine, won't know 100% until I get the motor running again.
 

rcr1978

Member
Apr 1, 2007
765
8
18
Spring Creek, NV
Does the lubegaurd stuff help the 5spd's with the G3's in the C3/C4? I have the 5-4 & 3-2 harsh no throttle downshift, seem's to be a C3 release issue the frictions are just to grabby wich is a good thing most of the time. Mine even carries on in reverse after moving the shifter to nuetral for a couple seconds when cold= grabby C3's. Just curious why I have never notice the C4's doing the same thing? I always thought it was a the release timing for the C3's and TCM tuning that's unobtainium would be the only fix? I have never felt it in a built 6sp and it's not everytime in the 5spd's kinda intermittent for all the ones I've been around and it's only been those two downshift scenarios coasting with no throttle input and worse when trans is cold.
 
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20dmax08

Member
Apr 13, 2018
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0
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Didn’t help my truck out. Also changed the speed sensor in the transfer case. Must be something else going on shifts hard on all the odd number gears. Might have take it into trans shop unless there’s any other ideas???


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OleBlackyLBZ

Active member
May 22, 2020
154
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Didn’t help my truck out. Also changed the speed sensor in the transfer case. Must be something else going on shifts hard on all the odd number gears. Might have take it into trans shop unless there’s any other ideas???


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I don't have mine running again yet so can't say for sure there. But my cousins has started doing it pretty bad and his trans is stock except a trans-go shift kit with 260,000 miles on it.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
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Disneyland, CA
Lube Gard will only help aggresive clutches. There are other reasons why the Allisons will downshift hard. Rear wheel sensors, driveshaft yoke, or weak grounds in the electrical system to name a few.
 
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OleBlackyLBZ

Active member
May 22, 2020
154
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I'm betting my problem is rear wheel sensors, they haven't been changed in 280,000 miles that I know of and I've already swapped to the nickel plated slip yoke. Thanks Mike, that's something I'm going to look into after I get the truck running again!
 

20dmax08

Member
Apr 13, 2018
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I will check mine also. Mine I’m fairly certain now is electrical. Sat in shop most of the winter only came out for ice fishing and hunting so maybe the moisture got to something.


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20dmax08

Member
Apr 13, 2018
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Was hoping it was rear wheel sensors but my truck doesn’t have them. Thinking my problem is internal. I changed internal filter and oil. Oil was clean. I get crazy hard shifts on 1,3,5. Also getting a flare on 5 now. Fack.


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