dantj

I have a 4l65e in my wrangler with an lq4 in front of it. having shift problems from 1-2, shift times are anywhere from .8sec to 1.7sec depending on throttle. also, getting a yo-yo bouncy shift when going WOT from 4th down to 2nd. zero codes in the computer, of course i think it has to do with the tune. the damn thing wont throw codes for anything engine related unless a sensor is unplugged. tuner says shift times are set at 0 with hptuners.

engine is fully sealed up with no vac leaks i can find. TPS checks out good, maf checks out good, and have swapped it with a known good sensor. trans temps are around stay around 150-165. haven't had a chance to drop the pan, however i did suck about a gallon of fluid out tonight and replaced it with some fresh fluid to see if it helped, of course it didnt.

i have a few 4l60e trans's laying around from 99-06 tahoes, yukons, and trucks, all with different problems so i have trans's i can steal parts from to test.

anywhere i should start?

EDIT: Its a 4l65e, confirmed the top bolt hole.

mrvedit

You might want to read and follow this current thread:

https://ls1tech.com/forums/automatic...nead-help.html

Any chance you have a trans pressure gauge? It would be good to know the line pressure during the shift. This would help confirm that the tune and pump pressure are OK.
Assuming line pressure is OK, this sounds like either a worn band or servo problem. As I state in post #4 of the other thread, it would also help us to know how much end play your servo has.
If the servo is easy to remove, you could just remove it and check the 2nd apply piston for cracks or bad seals. A new servo seal kit is less than $10.

dantj

Yeah i think i have one somewhere. I'll hook it up tomorrow after work. Would picking up the vette servo kit be a good idea if i'm gonna be doing seals anyways?

Dynamic396

What year is the transmission in there now?

Yes, a Vette servo is much better than the original one, but don't look for it to solve your problem. You have a pressure control issue...

dantj

Top of the transmission says 98-02 silverado. it was supposed to have been rebuilt, i pulled the whole package out of an 01 yukon denali. looked like a jy trans to me.

Also, have a tech 2 if theres anything i can check on that to help.

Dynamic396

OK. You should still have the Holley EPC solenoid in that year of transmission. If it was an '03 or newer, you would have the Delphi EPC and I would say to replace it immediately. They are notorious for sticking, which can cause the symptoms you describe.

I would still pull the pan and look at the EPC solenoid. If it has the electrical connector on the side of it (as opposed to it being on the end), you have the Delphi. If you do, put a new one in...

The Holleys CAN stick, but I don't find this to be the case very often.

dantj

Okay couldn't find a line pressure gauge today. Gonna try to buy one tomorrow. Dropped the pan, found a bit of clutch material, nothing too crazy. Decided to say screw replacing individual components, so i grabbed a spare 4l65e core that i had. (clutches smoked because someone forgot to put a filter in it after rebuild) Swapped the entire valve body, gaskets, and plate. My trans had a transgo 46-96 plate in it, and the accumulator? had some sort of HD spring in it. I left the accumulator alone, it was in good shape but swapped in a stock plate and valve body along with the wiring harness. 1-2 shift has improved from what i can tell, but i haven't done any WOT runs. reset the TAP data with the tech 2 and drove it a bit to relearn it. I'll beat on it tomorrow and report back.

mrvedit

That is incorrect and due to mis-information (from Maddog - haha) and other places.
The top bolt hole indicates it is a '98 or later 300mm input shaft trans designed for LS engines.
4L65E started to come in in 2003; there is NO external identifier of a 4L60E versus a 4L65E.

If you put the Corvette servo in, I would drill the 2nd feed hole to .082 (.073 is stock) -and- the 3rd feed hole to .093 (.078 is stock).

Its great that you had another valve body to swap in; that eliminates a lot of potential problems. Still think you have either low pressure and/or a worn band. Are you able to measure the servo end play?

Dynamic396

I guess I'll mention it one more time... What type of EPC did it have? The Holley or the Delphi?

mrvedit

Since the OP is willing to get and hook up a pressure gauge, don't you think we should wait for those results before worrying about the EPC? If the pressure varies from e.g. 60 to 200psi depending upon throttle position, the EPC is fine. If it seems stuck at one value, replacing the EPC is the easiest first thing to try.

Dynamic396

You may see it on a gauge, but probably not. It happens quickly enough that you probably won't catch it.

No matter. I'll leave it be. Just trying to help and thought I'd share a bit of "I-do-this-crap-every-single-day" experience...

dantj

The VB i pulled out had a connector that slid on the back, the new one comes off the side. I swapped the entire harness to eliminate any source of issues. Should i switch them back?

mrvedit

I assume you are referring to the connector on the EPC.
Dynamic396 prefers the EPC which has the two flat-blade connectors on the back; newer EPC (delphi) have a connector on the side (connector is more like the shift solenoids). If you swapped EPCs and have the same problem, then it isn't the EPC.
Sounds like you swapped the VB too.
Did that answer your question?

Dynamic396

It's not necessarily that I prefer one over the other, it's just that I have not seen the older Holley solenoids (connector on the end) fail nearly as often as the Delphi solenoids (connector on the side). I just wanted to eliminate a sticking Delphi EPC as the culprit, which it appears that you have by swapping an entire valve body and harness and having the problem still there.

mrvedit

Jon, you really don't think that a slipping band is the likely cause?
(I always defer to your experience.)

Dynamic396

I have no doubt that the band is slipping during the shift. But the question is why..? Is it worn out, or is it being applied with reduced hydraulic pressure, resulting in an excessive amount of time for the servo to stroke? Usually a band that is so worn that it slips will slip any time a load is applied to it, not just during the shift. Slow and lazy shifts with extended shift times, but that do finally engage are, more often than not, a pressure issue. Lazy shifts that never really fully engage are generally more likely to be a failed clutch or band.

If it's worn out, then it's worn out, but I was just trying to save him from an unnecessary tear down by sharing something that I deal with on a fairly regular basis with the Delphi solenoids as they age. Many shops are all too happy to sell you a build and in the process of that build (that you didn't need...) replace the solenoid that was ultimately the cause of the shift problem. I don't do things that way in my shop.

mrvedit

Dynamic396 - thank you for the detailed description, very informative to me and the OP.