Firmer 2-3 shift
Firmer 2-3 shift So I've built several 4l60es in the last 2 months and it's becoming sort of my new thing to do.
I'm looking for a firmer 2-3 shift. What do you guys end up doing for that? Usually a single cab silverado with a circle d 3600 stall or bigger is the application, 350-500rwhp
At the moment i do basic mods,
fitzall afl valve
vette servo
transgo hd2 kit, .500 boost valve, no shims on 1-2 accumulator, block 3-2 valve with the purple spring they provide, use that spring on AFL, iso conv valve.
Block 4th accumulator, just jam a checkball in there. Leave piston out.
Raybestos band, clearance usually 60 thou
Stock pump slide spring, stock rings
3-4 clearance .030"
check for leaks on input, i fix if they do leak.
Sonnax o ring bore plugs
upgraded bw sprag
2-3 feed hole .125"
1-2 .092
4th gear .125
br .092
Don't touch afl hole,
This is all on trans go plate
what are you guys doing to firm up that 2-3 shift? It shifts fine, but I guess I'm used to 80es and th400s that I can really feel the 2-3 shift.
They shift plenty fast like I mentioned, but its a soft feel. No flaring either.
I tune for a living so rule that tuning part out.
I'm looking for a firmer 2-3 shift. What do you guys end up doing for that? Usually a single cab silverado with a circle d 3600 stall or bigger is the application, 350-500rwhp
At the moment i do basic mods,
fitzall afl valve
vette servo
transgo hd2 kit, .500 boost valve, no shims on 1-2 accumulator, block 3-2 valve with the purple spring they provide, use that spring on AFL, iso conv valve.
Block 4th accumulator, just jam a checkball in there. Leave piston out.
Raybestos band, clearance usually 60 thou
Stock pump slide spring, stock rings
3-4 clearance .030"
check for leaks on input, i fix if they do leak.
Sonnax o ring bore plugs
upgraded bw sprag
2-3 feed hole .125"
1-2 .092
4th gear .125
br .092
Don't touch afl hole,
This is all on trans go plate
what are you guys doing to firm up that 2-3 shift? It shifts fine, but I guess I'm used to 80es and th400s that I can really feel the 2-3 shift.
They shift plenty fast like I mentioned, but its a soft feel. No flaring either.
I tune for a living so rule that tuning part out.
Last edited by subeone; Apr 26, 2023 at 11:36 PM.
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What are you running the line pressure at?
I drill the 2-3 shift feed hole to .155" with a 3600 stall or bigger convertor.
I don't think you will ever get it to feel like a th400 or 4L80e.
I drill the 2-3 shift feed hole to .155" with a 3600 stall or bigger convertor.
I don't think you will ever get it to feel like a th400 or 4L80e.
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From: BERWICK PA
With hole size that large you should be getting about as much as you can get , But note that stalls gonna hide a lot of it. I do a Mod with the 2-3 valve that speeds things up I will try and find a photo later. And as was asked what is your line pressure at? Ideally IMO you want about 220 PSI at WOT. However, I do not think you will ever get old school 400 bark the tires on 2-3 with a 60e unless you are geared really low and got some thin tires , Nor IMO would you really want all that. The 60e living is a careful balance of shift firmness and hard parts strength. Really harsh equals beat the crap out of hard parts and break stuff.
Only other things I can think of is sonnax 2nd servo will give a little less 3rd accumulation or and not real fond the superior pancake style 2nd servo pretty much eliminates 3rd accumulation. I only use the .092 on the 2-3 and it plenty firm enough for me with a vette servo and a 2800 stall. Note if you use the superior second servo with sonnax 4th servo you will need to replace to gold washer with one of the stock washers from under the pin clip else you will have an interference issue as band wears. But reality the superior second servo with no accumulation is about the only big change I think you could do to get anywhere close to where you want, again not a fan of it very clunky feeling in normal driving on the 2-3 3-2
Only other things I can think of is sonnax 2nd servo will give a little less 3rd accumulation or and not real fond the superior pancake style 2nd servo pretty much eliminates 3rd accumulation. I only use the .092 on the 2-3 and it plenty firm enough for me with a vette servo and a 2800 stall. Note if you use the superior second servo with sonnax 4th servo you will need to replace to gold washer with one of the stock washers from under the pin clip else you will have an interference issue as band wears. But reality the superior second servo with no accumulation is about the only big change I think you could do to get anywhere close to where you want, again not a fan of it very clunky feeling in normal driving on the 2-3 3-2
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Last edited by FranksCustomTrans; Apr 27, 2023 at 11:14 AM.
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I knew of a full blown transmission shop that wouldn't use VB gaskets on 700R4's. The builder said that it fixed all the trouble they had with them. Externally I acted like I just learned a secret, Internally I thought "dumb-***" . 2 years later that same builder was doing drywall work...
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From: BERWICK PA
Whie I definitely do not subscribe to this idea , I have in fact torn units down that have been in service years with no VB gaskets. I was like OK and they were 700r4s
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From: BERWICK PA
If you leave the ball out you will just be at the feed hole size though the shaft and that .152 hole size mentioned is already about that so would really make little if any difference.
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Last edited by FranksCustomTrans; Apr 29, 2023 at 01:20 PM.
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Older Chrysler's like the 727, 904, A500 A518/618 never used a VB gasket and got away with it. How many thousand did they produce and didn't use a gasket. Wet stone the VB, Plate & Case and they are good to go...