i bought the 77898e-k kit and after reading i measured the epc spool on the original, and found that the original was a .421, can i still install the .490 without damaging the tranny? or do i need to get the 77898E-4K?

 

What year is the transmission?

 

Is this a V6 transmission?

 

it's a 2002 k1500 with a 5.3l thanks

 

Since your 2002 trans is pre-ISS (pre Input Speed Sensor), it will take the longer Sonnax 4L60E-LB1 boost valve. Not sure which kit has that boost valve, perhaps clinebarger knows.

 

In the Performance Pack they provide a shim for the older 60Es to make up the difference.

 

I do understand that there is a length diff. between the pre iss and post iss why i am confused is this statement from sonnax

1.907" Long Sleeve.421"Valve:
Sonnax 77898E-4K may be used, but noticeably firmer shifts will occur.
No Sonnax ratio available.

the reference where is says from a .421 a Sonnax 77898E-4K may be used, but noticeably firmer shifts will occur. which is a .470 sized piston,

I purchased the 77898E-K which is a .490, by mistake, and I'm just wondering if it will cause problems down the road, Transgo sells a boost kit also, and they say it's a .500 piston with no exceptions but early and late models, personally i don't think it will hurt, but while the tranny is still tore down i just wanted to ask the question, doing a google search doesn't really answer my question,
Thanks for your input

 

.421" is a V6 boost valve size, Not recommended for V8 engines.

.470" is the stock V8 boost valve size.

.490" is a exclusive Sonnax performance boost valve.

The .490" is a nice upgrade behind all V8 engines, The only shift that will be noticeably affected is the 1-2....But with a small 553 2nd piston it probably won't be that bad.

 

The 4L60E-LB1 & 4L60E-LB2 are kits that include a PR spring, The OP is looking at Boost Valves that do not come with a PR spring.

 

Correct, But that only comes in their shift kit, They have different part numbers when purchasing the boost valves separately.

 

Huh go figure. I just checked the Sure Cure instructions and the only info provided is:

Dump the patent number into Google.

https://static.summitracing.com/glob...-4l60e-lb1.pdf
http://kaztranz.com/uploads/Sonnax_Binder.pdf

 

well that explains alot,, I want to thank everyone for their input, I'm really hoping the rebuild turns out good