2bfast Posted July 13, 2011 Report Share Posted July 13, 2011 (edited) Alright been doing a little research on the recent failure that occured to my 60E. For all that have been under a rock, bout a month ago when using the nitrous for the first time the trans failed to engage 2nd gear, bounced off the rev limiter (7200rpm) and sheered the forward sprag. See picture ....... I am told that if left in 3rd instead of O/D, the overruns are applied during the 2-3 shift, and actually starves the 2-3 clutch for oil in doing so, hence it's bad to race in the non overdrive position with a 60E and stock valvebody. So, even in 3rd position you still don't have the overruns supporting the sprag until 3rd gear, in which it really doesn't need the extra support like it does on a standstill launch and a slamming 2nd shift. But when you look at this chart, is shows the overruns are applied 1st, 2nd, and 3rd? I had found a mod from Sonnax called the 2-3 shift valve mod. Essentially the new valve goes on the end of the 2-3 shift solenoid. It blocks off the hydraulic passage that is opened up on the 2-3 shift going to the overrun's, and you then drill a hole through the casting to feed the overrun's in all forward ranges, not just after the 2-3 shift. This way it's supporting the sprag all the time. Just kinda confused, I do see the point of the mod and would be very easy to complete especially since I have the valve body off already but according to the chart they are applied anyhow. Tell me im missing something....... Edited July 13, 2011 by 2BFAST (see edit history) Quote Link to comment Share on other sites More sharing options...
sprayed99 Posted July 13, 2011 Report Share Posted July 13, 2011 Alright been doing a little research on the recent failure that occured to my 60E. For all that have been under a rock, bout a month ago when using the nitrous for the first time the trans failed to engage 2nd gear, bounced off the rev limiter (7200rpm) and sheered the forward sprag. See picture ....... I am told that if left in 3rd instead of O/D, the overruns are applied during the 2-3 shift, and actually starves the 2-3 clutch for oil in doing so, hence it's bad to race in the non overdrive position with a 60E and stock valvebody. So, even in 3rd position you still don't have the overruns supporting the sprag until 3rd gear, in which it really doesn't need the extra support like it does on a standstill launch and a slamming 2nd shift. But when you look at this chart, is shows the overruns are applied 1st, 2nd, and 3rd? I had found a mod from Sonnax called the 2-3 shift valve mod. Essentially the new valve goes on the end of the 2-3 shift solenoid. It blocks off the hydraulic passage that is opened up on the 2-3 shift going to the overrun's, and you then drill a hole through the casting to feed the overrun's in all forward ranges, not just after the 2-3 shift. This way it's supporting the sprag all the time. Just kinda confused, I do see the point of the mod and would be very easy to complete especially since I have the valve body off already but according to the chart they are applied anyhow. Tell me im missing something....... Did you call my pops and run this by him? Quote Link to comment Share on other sites More sharing options...
2bfast Posted July 13, 2011 Author Report Share Posted July 13, 2011 (edited) Did you call my pops and run this by him? Called monday and got his voicemail, havnt tried back yet Edited July 13, 2011 by 2BFAST (see edit history) Quote Link to comment Share on other sites More sharing options...
SSplaytoy Posted July 13, 2011 Report Share Posted July 13, 2011 You're missing something Good info to know, especially since my truck likes getting stuck in 3rd. Hopefully this thread will give me better insight into the 4l60. I would think that the hole would cause a decrease in pressure and I'm not sure what that would cause. Quote Link to comment Share on other sites More sharing options...
2bfast Posted July 13, 2011 Author Report Share Posted July 13, 2011 I would think that the hole would cause a decrease in pressure and I'm not sure what that would cause. I can see where you would think that, but all you are doing is modifying the hydraulics and that is what the valve is for not just the hole to feed the clutches Quote Link to comment Share on other sites More sharing options...
SSplaytoy Posted July 13, 2011 Report Share Posted July 13, 2011 So if that's what the valve is for, there really isn't a need for the hole Quote Link to comment Share on other sites More sharing options...
2bfast Posted July 13, 2011 Author Report Share Posted July 13, 2011 (edited) So if that's what the valve is for, there really isn't a need for the hole The valve blocks off the hydraulic passage that is opened up on the 2-3 shift going to the overrun's, and you then drill a hole through the casting to feed the overrun's in all forward ranges, not just after the 2-3 shift is what im seeing from this. But my question is from the chart, the overruns are applied in 1st - 3rd but im told they are only really applied 2-3 Edited July 13, 2011 by 2BFAST (see edit history) Quote Link to comment Share on other sites More sharing options...
sprayed99 Posted July 13, 2011 Report Share Posted July 13, 2011 Called monday and got his voicemail, havnt tried back yet call after 6:30 and try him today. Oh and try leaving a message Quote Link to comment Share on other sites More sharing options...
zippy Posted July 14, 2011 Report Share Posted July 14, 2011 I can see the idea of basicly running the overrun set any time you're in forward gear. Something to keep in mind is that in the case of what happened to you I feel it would have just slipped the overrun set (they are tiny and not made to handle much strain) and still broke the sprag. The only advantage I would see from this would be increased forward clutch life under heavy stress. Another problem I see would be harsh downshifts while just driving around and any jerking on the hard parts of the trans is bad. For all out racing, constant overrun apply would be fine. I have heard of this done, not much to report from it though on either side. I've never done this for the same simple reason that you haven't had to yet. If we can get your shifts to work properly between tuning and trans work you won't need this. Just need to shoot for a second 10 second SSS with a 65E. What is cool is that 7200rpm with 10+psi of boost and nitrous and your engine is fine. You don't need a new engine, but heads would be nice. Have you ever thought of re-gearing your 65E? I'm waiting for someone to do this. Taking away that huge 1-2 shift split and I bet alot more power could be put to these transmissions. Quote Link to comment Share on other sites More sharing options...
misterp Posted July 14, 2011 Report Share Posted July 14, 2011 (edited) ...I am told that...the overruns are applied during the 2-3 shift, and actually starves the 2-3 clutch for oil in doing so... To me, this is a flawed argument - the instant you put the shifter into "3rd range" the overruns are 'activated' i.e. pressurized with feed oil and they are left pressurized the whole time while still in "3rd range" regardless of gear. My point is, the overruns clutch pack servo is already filled with pressurized oil as the trans is pulling in 2nd gear, then when the 2-3 gear change happens yes there is an interruption of feed pressure for a split second but I do not believe the oil in the overrun circuit has time to completely exhaust before that circuit is 'restored' as Solenoid-B is turned off. When Solenoid-B turns off, it re-opens that feed passageway to the overruns, but that passage is already (mostly?) full of oil so there will be very little volume of feed oil required to reapply the overruns servo for the next gear. In logging my 4L60 transmission pressure during the 2-3 shift there is very little pressure drop in the system, not enough to call it 'starvation' (it falls from 280-psi to 265-psi for about 1-2 tenths of a second). ...when you look at this chart, is shows the overruns are applied 1st, 2nd, and 3rd?... Yeah I would call that an authoritative answer! Mr. P. p.s. - we should have your gauge back to you next week! Edited July 14, 2011 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
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