4l60e flare up
My 4l60e lost 3rd so over the holiday I decided to go through it myself. I found the cause of the problem was the input shaft and mating stator were badly worn. I visited a local trany shop that helped me out with parts. I got a used input housing and they pressed a used stator into the pump cover. They did not have a refurbished pump cover but did have a body ready so I picked it up as well.
I have it back in the van but as you could probably guess something isn't right. On light acceleration it seems to shift ok but any more and you get a slight flare up on 1-2 shift. 2-3 flare up is much worse and you have to let off the gas for it to catch on heavy acceleration. It only acts normal once it locks up. I hooked up a pressure gauge and get 70 in D and 90 in reverse. I drove it with the gauge hooked up and the highest pressure was 110 when I floored it from a stop. I noticed a few times the gauge would start jumping up and down about 10psi. This was just around the block. Didn't want to drive it to much.
I'm thinking the shift flare might be caused by low pressure. With my pump being the start of the 13 vane pump would a older body mixed with my cover cause low pressure? I would hope the guy at the shop new what he was giving me. I have read that the sonnax boost valve might help my issue.
I would greatly appreciate any help to get me going.
Thank you
http://www.ebay.com/itm/4L60E-4L65E-...5d4148&vxp=mtr
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Carsonauto is way more experienced then me, and his comments all sound correct. I think it it just bad luck, either the pump was more worn then expected, installing the stator shaft bent the case a bit, or in a rush it was not assembled right. I would check for the O-ring under the pump slide if it is ever opened up again. Also that that the boost valve and pressure regulator valve are assembled correctly.
A Sonnax boost valve might still be a good idea as it includes O-rings to account for any bore wear. I have no idea if excessive bore wear could cause this problem. At least it can be installed without dropping the trans.
Last edited by mrvedit; Feb 15, 2013 at 08:37 AM. Reason: Correction - originally wrote "rotor", meant "slide"
I ordered all the parts from Oregon Performance Transmission. That box was packed really tight. I can understand the filter getting broke if the box was thrown around.
Last edited by nxk2000; Jan 8, 2013 at 12:47 AM.
Only the PCM via the Shift solenoids determine when the trans shifts, but the line pressure, separator hole size and accumulator springs determine how long the shift actually takes and how it feels.
For the 1-2 shift the hydraulic fluid has to fill the 1-2 accumulator and move the 2nd-apply piston in the servo and band before the shift is complete. Any type of problem or leak in the accumulator or servo, or a too-loose or too-tight band could dramatically slow the shift and/or make it slam.
I don't have the experience to suggest whether your problem is more likely the accumulator, servo or band. Fortunately these can all be checked and likely corrected without removing the trans.
You probably already know that the 1-2 accumulator can easily be checked - you only have to drop the pan and remove its three bolts. There are numerous reports of broken springs and cracked plastic pistons causing problems. An aluminum piston is a suggested $2 upgrade.
Perhaps someone more experienced can give you more specific guidance.
Easiest thing that I would do first is pry in on the servo cover and see how much travel it has before it bottoms out. That will tell you a lot about how far the servo has to move to before it applies the band. If it moves more than 1/8" its too much If it moves a lot more than 1/8" its most likely the issue.
Wether it burnt up the band or not is another question all together. If it only moves 1/8" or a little less then its good as far as band clearance but there very well could still be an issue with the servo and its easy enough to take out in the vehicle. Especially in an astro van, There is almost enough room to throw a party under one of those compared to most vehicles... I have put servos together before and had the scarf cut sealing ring on the O/D of the 2nd piston pop off and I never knew it until second gear didnt work so good.
The band seemed to have a bit more then 1/8 of movement. In the left over parts that I still had from that trans go kit was a gold ring that I believe is used to take up some of the play. Should I use that ring or try a longer pin?
https://ls1tech.com/forums/automatic...questions.html
If you are not sure what springs you have in the 1-2 accumulator, I would start with the two stock ones. I could send you a pair if you cannot locate them. Was the Transgo Boost valve installed? Was the separator plate drilled to the Transgo instructions? All these things work together to give proper shift feel; i.e. installing half the kit might give you strange feeling shifts.
Yes, you can install the Transgo gold rings to tighten up the servo. See the Transgo instructions in the link above.
http://www.tonkinonlineparts.com/sho...ssembly=839050
The springs I have are like this picture 54A and 54B but I have 2 of the 54A but one fits inside of the other and 1 of the 54B. I figured I would try pulling out one of them just didn't know which or if it even matters which.
As 08GXPLS4 suggests, the accumulator valve (actually regulates both 1-2 and 3-4 accumulators) can stick in its bushing (sleeve) after many miles and affect the shift feel. The valve body needs to be removed to check it. (I'll admit that I once installed the bushing up-side-down and it still shifted just fine.)
It does also seems likely that your band has worn down, making the servo pin loose. Perhaps tightening that up with one or two Transgo rings will give your trans more life.






