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So can I use the 2nd type housing ending in 428 in place of a housing ending in 937 (last style) shown.I measured both bolt hole distances on these housings the look exactly same distance apart one seems to just be alittle deeper bore(937). I wonder if I can if it would firm up shifts it being a shorter bore
? Or is the 937 housing better? Any other tips going to install sonnax pinless piston have both 2 nd and 3rd style which one would be better? And I have OEM springs for both and a purple sonnax spring? Any help would be appreciated doing this tomarow along with my fwd accumulator.
Left (937) right(428) with OE springs next to their housing seems like they could be interchanged?
I Have a 2001 4l60e in a 5.3 l Silverado by the way if this helps anyone's suggestions thanks.
RobPH you should start your own thread instead of high jacking this one.
As moderator, I have created a new thread.
Yes, you can interchange the 937 and 428 1-2 accumulator housings. I don't think it will matter which one you use. The 937 housing will hold the base of the springs better, but the 428 will firm up the shifts with its shorter bore. I would use the Sonnax spring with the stock inner spring. If too firm, you can remove the inner spring. If not firm enough, you can add washers under the springs to get the shift to your liking. Be careful doing this, if you get the shift too hard you may start braking hard parts, like the forward sprag or wear the sun shell and reverse input drum.
Last edited by mrvedit; Jun 5, 2022 at 08:13 AM.
Reason: Moved to new thread, corrected spelling
RobPH you should start your own thread instead of high jacking this one.
As moderator, I have created a new thread.
Yes, you can interchange the 937 and 428 1-2 accumulator housings. I don't think it will matter which one you use. The 937 housing will hold the base of the springs better, but the 428 will firm up the shifts with its shorter bore. I would use the Sonnax spring with the stock inner spring. If too firm, you can remove the inner spring. If not firm enough, you can add washers under the springs to get the shift to your liking. Be careful doing this, if you get the shift too hard you may start braking hard parts, like the forward sprag or wear the sun shell and reverse input drum.
So which spring would be best to use the one that is original to the housing? I have a purple sonnax spring too 74926? The guy at sonnax also said to just use only the outer spring do not reuse the inner.
It is difficult to answer your question because it depends upon your personal preference and whether other changes were made, such as drilling the separator plate.
The Sonnax spring is advertised as " identical performance specifications to the purple OE accumulator spring". If you want something a bit firmer, I would add either the inner spring or place one washer under the Sonnax spring. And Mr Bond stated that the 428 housing would also firm up the shift with just the outer spring and/or one washer.
It is difficult to answer your question because it depends upon your personal preference and whether other changes were made, such as drilling the separator plate.
The Sonnax spring is advertised as " identical performance specifications to the purple OE accumulator spring". If you want something a bit firmer, I would add either the inner spring or place one washer under the Sonnax spring. And Mr Bond stated that the 428 housing would also firm up the shift with just the outer spring and/or one washer.
I thought a lighter tension spring under the piston into housing first firms shift and if facing separator plate would soften it's and firm in housing first would soften it?
Stiffer spring in housing and then piston will firm up 1-2 shift. With the Sonnax piston you can only install it with the spring in the case or it will bind up.
Stiffer spring in housing and then piston will firm up 1-2 shift. With the Sonnax piston you can only install it with the spring in the case or it will bind up.
Got em all done and solenoids all besides EPC my forward was aluminum stock thought it would be plastic like my 1-2 but it wasn't put in a new one with new spring anyway I used a transgo aluminum alloy. I ended up having a 428 style housing in my 01 I just used only the outer spring no inner I'll update tomarow after test drive thanks.
Seems to shift about the same with just the outer spring maybe alittle firmer I think if light spring is under housing it does shift more firm. Sonnax enchanched spring 77704S directions instruct you to put it facing separator plate or you will get a softer than OE shift and that spring is super firm heavy duty so I think light tension spring into housing first does firm shifts.
If you put a spring on both side of the sonnax pinless piston it will not work correctly. there will not enough travel toward the open end of the piston.
Instructions for the Sonnax pinless piston.
1-2 Piston: Install spring(s) into accumulator body, set piston pocket opening onto spring, dome toward plate
If you put a spring on both side of the sonnax pinless piston it will not work correctly. there will not enough travel toward the open end of the piston.
Instructions for the Sonnax pinless piston.
1-2 Piston: Install spring(s) into accumulator body, set piston pocket opening onto spring, dome toward plate
I didn't put a spring on both sides just used one spring the big outer one. I put spring into housing first then pinless piston.
Flip the Spring and Piston orientation from your last Post, and use a slightly firmer Spring.
Or keep the orientation the same, and use a much softer Spring.
Flip the Spring and Piston orientation from your last Post, and use a slightly firmer Spring.
Or keep the orientation the same, and use a much softer Spring.
Yes thanks that's what I thought would happen that's what I did used softer spring in same orientation and no inner it def shift more firm now.
Stiffer spring in housing and then piston will firm up 1-2 shift. With the Sonnax piston you can only install it with the spring in the case or it will bind up.
This makes the shift softer
Firm shift is:
housing-->piston-->spring-->separator plate
In this orientation, the stiffer the spring, the firmer the shift
Soft shift is:
Housing-->spring-->piston-->separator plate
in this orientation, the stiffer the spring, the softer the shift
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1-2 Accumulator questions 
