TSI Racing Rebuilt 4L60E's Overrun Sprague Assembly Broke, what's better?
07-15-2014, 01:40 AM
#21
"Less than a year later after one visit to the strip and one weekend at Road America and plenty of spirited street driving, my "Beast" Sunshell broke and I lost drive and overdrive and only have gears 1 & 2,"
If this statement is correct, you did not lose the sunshell as when that happens you will lose reverse, second and fourth, and will have first and third only.
If you did lose the sunshell and he transmission shifts hard all the time, there is your problem and the solution is to work with the second accumulator (and not against it) to soften the part to medium throttle shifts and to have a quick but not overly firm WOT shift. I have the late GM heat treated sunshell in a few nine second vehicles without any problems, so the Beast should do just fine. So if your transmission is shifting quick but not firm at part to medium throttle now, then I would suspect the sunshell to have been bad from the beginning with a void or crack in it.
If this statement is correct, you did not lose the sunshell as when that happens you will lose reverse, second and fourth, and will have first and third only.
If you did lose the sunshell and he transmission shifts hard all the time, there is your problem and the solution is to work with the second accumulator (and not against it) to soften the part to medium throttle shifts and to have a quick but not overly firm WOT shift. I have the late GM heat treated sunshell in a few nine second vehicles without any problems, so the Beast should do just fine. So if your transmission is shifting quick but not firm at part to medium throttle now, then I would suspect the sunshell to have been bad from the beginning with a void or crack in it.
07-15-2014, 02:24 PM
#22
Edited my previous post above, it is the 5 gear planetary from GM I meant.
Also upon tear down it actually was not the sunshell that broke (that was the early assumption), it is the Input / overrun sprague assembly that broke & took out 3 & 4 clutches...
Also upon tear down it actually was not the sunshell that broke (that was the early assumption), it is the Input / overrun sprague assembly that broke & took out 3 & 4 clutches...
Last edited by libertyforall1776; 07-15-2014 at 02:59 PM.
07-15-2014, 05:16 PM
#23
Moderator
It is all making more sense now; thanks for the update.
The forward sprag is a(nother) weak point in the 4L60E with many failures reported here.
I recommend the BorgWarner dual-cage sprag and installing the Sonnax HD 2-3 shift valve which changes the hydraulics to keep the overrun clutch always engaged when the shifter is in the [D3] position. This reduces the load on the sprag when you race in [D3].
I heard a rumor about a stronger sprag and therefore bought a brand new sprag from the dealer for a late model 4L75E. $250 later it looks just like the sprag from e.g. a 2009, although both look stronger (dual cage) than what came in a '01. I don't know if e.g. FLT, RPM and Performabuilt have a "secret" sprag in the top-of-the-line 4L65E, but to handle the advertised 750-1000HP I think the sprag needs to be stronger.
The forward sprag is a(nother) weak point in the 4L60E with many failures reported here.
I recommend the BorgWarner dual-cage sprag and installing the Sonnax HD 2-3 shift valve which changes the hydraulics to keep the overrun clutch always engaged when the shifter is in the [D3] position. This reduces the load on the sprag when you race in [D3].
I heard a rumor about a stronger sprag and therefore bought a brand new sprag from the dealer for a late model 4L75E. $250 later it looks just like the sprag from e.g. a 2009, although both look stronger (dual cage) than what came in a '01. I don't know if e.g. FLT, RPM and Performabuilt have a "secret" sprag in the top-of-the-line 4L65E, but to handle the advertised 750-1000HP I think the sprag needs to be stronger.
07-15-2014, 06:38 PM
#24
So I am going with the 5-gear planetaries -- replacing both which have 4-gears today, even though only one has loose gears -- I think it's good insurance to help keep everything centered.
Yes, going with a BorgWarner sprag assembly, as for racing in D3 -- do many do so and if so what is the benefit? I have not, so if I were not going to do so, there is no reason for this shift valve I assume?
Anything else I should be considering? I am now also buying a full-length torque-arm to get that sucker off the trans tailshaft -- wonder if that stock arm assisted this failure?
Yes, going with a BorgWarner sprag assembly, as for racing in D3 -- do many do so and if so what is the benefit? I have not, so if I were not going to do so, there is no reason for this shift valve I assume?
Anything else I should be considering? I am now also buying a full-length torque-arm to get that sucker off the trans tailshaft -- wonder if that stock arm assisted this failure?
The forward sprag is a(nother) weak point in the 4L60E with many failures reported here.
I recommend the BorgWarner dual-cage sprag and installing the Sonnax HD 2-3 shift valve which changes the hydraulics to keep the overrun clutch always engaged when the shifter is in the [D3] position. This reduces the load on the sprag when you race in [D3].
I heard a rumor about a stronger sprag and therefore bought a brand new sprag from the dealer for a late model 4L75E. $250 later it looks just like the sprag from e.g. a 2009, although both look stronger (dual cage) than what came in a '01. I don't know if e.g. FLT, RPM and Performabuilt have a "secret" sprag in the top-of-the-line 4L65E, but to handle the advertised 750-1000HP I think the sprag needs to be stronger.
I recommend the BorgWarner dual-cage sprag and installing the Sonnax HD 2-3 shift valve which changes the hydraulics to keep the overrun clutch always engaged when the shifter is in the [D3] position. This reduces the load on the sprag when you race in [D3].
I heard a rumor about a stronger sprag and therefore bought a brand new sprag from the dealer for a late model 4L75E. $250 later it looks just like the sprag from e.g. a 2009, although both look stronger (dual cage) than what came in a '01. I don't know if e.g. FLT, RPM and Performabuilt have a "secret" sprag in the top-of-the-line 4L65E, but to handle the advertised 750-1000HP I think the sprag needs to be stronger.
Last edited by libertyforall1776; 07-15-2014 at 06:47 PM.
07-15-2014, 06:48 PM
#25
Moderator
Here is more info about the Sonnax HD 2-3 shift valve:
https://ls1tech.com/forums/automatic...ure-flare.html
We have had other discussions about it, and performance builders like Jake called it "essential".
The only benefit to racing in [D3] is if you have that valve, otherwise race in [OD]. The valve's benefit is that the engine load is split between the sprag and the overrun clutches, instead of all being applied to the sprag.
If your builder is switching to 5-pinion planets, note that GM's more recent 5-pinion planets require the new (2007?) style reaction carrier shaft and matching bearing. Otherwise it will not center properly and quickly fail. I discuss this in detail starting around post #11 in this thread:
https://ls1tech.com/forums/automatic...n-planets.html
https://ls1tech.com/forums/automatic...ure-flare.html
We have had other discussions about it, and performance builders like Jake called it "essential".
The only benefit to racing in [D3] is if you have that valve, otherwise race in [OD]. The valve's benefit is that the engine load is split between the sprag and the overrun clutches, instead of all being applied to the sprag.
If your builder is switching to 5-pinion planets, note that GM's more recent 5-pinion planets require the new (2007?) style reaction carrier shaft and matching bearing. Otherwise it will not center properly and quickly fail. I discuss this in detail starting around post #11 in this thread:
https://ls1tech.com/forums/automatic...n-planets.html
07-16-2014, 12:26 PM
#26
^ thanks, yes it's the kit for the 5 gear planetary.
To correct my earlier post, it was actually the Input/overrun sprague hub that failed, the sprague itself was ok.
I will have to look into the Sonnax valve more, as if you do not correctly bore out that hole you could gain a whole host of new problems...
To correct my earlier post, it was actually the Input/overrun sprague hub that failed, the sprague itself was ok.
I will have to look into the Sonnax valve more, as if you do not correctly bore out that hole you could gain a whole host of new problems...
07-17-2014, 09:58 PM
#27
So with the 5 planetary gear kit, my 4l60e is now essentially a 4l65e internals now -- is that right? Looks like it:
http://www.carcraft.com/techarticles...on_conversion/
http://www.carcraft.com/techarticles...on_conversion/
07-20-2014, 07:39 PM
#28
Moderator
[QUOTE=libertyforall1776;18326990]So with the 5 planetary gear kit, my 4l60e is now essentially a 4l65e internals now -- is that right?
Yes, or at least mostly. As far as I know, the GM 4L65E also has a hardened input shaft; considering that input shaft breaks are not common, that is a minor detail. (More common than an input shaft break is the input shaft stripping out the input drum.)
Hopefully you new build will hold up now.
Yes, or at least mostly. As far as I know, the GM 4L65E also has a hardened input shaft; considering that input shaft breaks are not common, that is a minor detail. (More common than an input shaft break is the input shaft stripping out the input drum.)
Hopefully you new build will hold up now.
