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noobie
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Discussion Starter #1
Recently put pacesetter long tubes, y pipe, comp cams xr265hr cam, ls6 valve springs in my 5.3 sierra z71 4x4. Rebuilt the 4l60e with the transgo hd2 shift kit, vette servo and trailblazer converter. Had a local shop street tune it and it runs good but still seems like it's holding back. I have 20" silverado ss wheels with 275/55/20 cooper zeon tires. It has the gt4 3.73 gears. My thoughts were find a wrecked truck with 4.10's and swap the axles but will that be enough? I could go 4.56 and would cost alot more but would it be worth it? I was thinking maybe I needed a higher stall converter since the tb stalls around 2200 but even at highway speeds and higher rpms it seems like it's holding back. Any suggestions?
 

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The swap from 3.73 to 4.10 wouldn't be worth the change you'll get. 4.56 would be your best bet


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I blew out my G80 with 3.73s. I talked myself into 4.56s and last second went 4.88. I turn 2350 rpm @ 65 mph with 285/70r17 tires. You'd be @ 2,400 rpm with your tire. Go 4.56 it comes out to 2,240 rpm with your tire @ 65. The launches are awesome and the lower ratio helps tighten up the drop between gears in the 4L60e transmission.
 

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noobie
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Discussion Starter #4
Thanks where's the best place to buy quality 4.56 gears and install parts? I don't really care if the gas mileage sucks I'm getting 13-14 now I just want it to be fun to drive. I've never rebuilt a GM truck rear end but it can't be too bad right? I thought I was in over my head with rebuilding that 4l60e but took my time and it turned out great.
 

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Summitracing.com is good. You gotta do some reading. You gotta get the ring and pinion shimmed perfectly or else they eat eachother. Now by perfect I mean the width of a human hair apart.
 

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Mmm Sandwich
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There is a great sticky here that you can use to help you out
 

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I have 35s and went from 373s to 456s and man what a difference. Still wishing I had went 488s. If you do 410s you'll leave yourself wanting more. If mileage isn't a big concern for you do the 456s. Put a good posi in it too that's what I did. Never know when the stock g80 will blow out.
 

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Swapping the rear end ratio will NOT change the amount of rpm drop between gears. This can only be accomplished by either changing the transmission gear itself OR installing a looser torque converter.

The rpm drop is fixed, independant of your rear end gear.

peace
Hog
 

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Swapping the rear end ratio will NOT change the amount of rpm drop between gears. This can only be accomplished by either changing the transmission gear itself OR installing a looser torque converter.

The rpm drop is fixed, independant of your rear end gear.

peace
Hog
He never asked about rpm drop he said he feels like its still holding back!! I believe at this point gears would be more beneficial than a bigger stall. I got more out ta my 456s than I got from my 2200 FTI stall.
 

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go 4.56s and also get a better stall.
it will be a different truck
 

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He never asked about rpm drop he said he feels like its still holding back!! I believe at this point gears would be more beneficial than a bigger stall. I got more out ta my 456s than I got from my 2200 FTI stall.
No but 11 mpg did. I can read.

peace
Hog
 

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No but 11 mpg did. I can read.

peace
Hog
Sorry for the wording. Meant it as the 4L60 is too stretched out compared to a 4L80. Getting it geared lower helps with it being too long in the tooth. 0-32 for 1st and 32-56 for 2nd vs having to wait for 80mph to hit 3rd under WOT.
 

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i know you all are gunna hate me for this... but the now build 4:30s for the frount for us 4x4 guys i almost did this before i decided to pull the plug on boost. did alot of talking to Ron at ron's machine services and he had me sold on a set if i kept the truck N/A for running my 33's
 

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He never asked about rpm drop he said he feels like its still holding back!! I believe at this point gears would be more beneficial than a bigger stall. I got more out ta my 456s than I got from my 2200 FTI stall.
well i would hope so..... stock is 1800 put a 3200 stall in it and i bet you will change your feelings towards the stalls haha. Gears are great no doubt but especally once your off the line stall puts and keeps you in your power band.
 

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Sorry for the wording. Meant it as the 4L60 is too stretched out compared to a 4L80. Getting it geared lower helps with it being too long in the tooth. 0-32 for 1st and 32-56 for 2nd vs having to wait for 80mph to hit 3rd under WOT.
iirc the 4l80e has a higher and longer 1st compared to the 4l60e. That's what I was always told. If I'm wrong. Please correct me.
 

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iirc the 4l80e has a higher and longer 1st compared to the 4l60e. That's what I was always told. If I'm wrong. Please correct me.
4L80
1st: 2.48
2nd: 1.48
3rd: 1.00
4th: 0.75

4L60
1st: 3.06
2nd: 1.63
3rd: 1.00
4th: 0.70

The 4L60e has a wider distance between each shift compared to the 4L80e. Lower gearing helps with the bad bog you get hitting each shift.
 

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noobie
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Discussion Starter #18
I think before I change gears I'm going to try a different converter. I have a reman daco trailblazer converter and it seems to stall low around 2200. I can feel the power come on closer to 3000 so I bet that would help out a bunch. But pulling that tranny is going to suck just to change the converter
 

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I think before I change gears I'm going to try a different converter. I have a reman daco trailblazer converter and it seems to stall low around 2200. I can feel the power come on closer to 3000 so I bet that would help out a bunch. But pulling that tranny is going to suck just to change the converter
I'll be a new truck. Just keep an eye on the temps after the swap and yeah the whole process sucks. In my case a blown trans was the motivation for a new convertor.
 

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4L80
1st: 2.48
2nd: 1.48
3rd: 1.00
4th: 0.75

4L60
1st: 3.06
2nd: 1.63
3rd: 1.00
4th: 0.70

The 4L60e has a wider distance between each shift compared to the 4L80e. Lower gearing helps with the bad bog you get hitting each shift.
Ahhh. Thanks for that. So first is lower( numerically higher) but has more distance between the shifts.
 
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