Tranny going again---less than a year after rebuild:Assistance Please

[Grocery Getter]

Man, the hoe is really putting it to me this month..looks like I'll need a new fuel composition sensor and to boot my tranny is going to shit. I just had it rebuilt with everything in a 4L65E but the 5 pinion rear planetary.....

I am losing 1st in OD, it will sometimes rev high then engage and sometimes not engage at all. It will also shudder/shake when in first at low speeds and sometimes while going into 2nd. If I put it in 1st the problem seems to go away and I can shift manually from 1st-OD and while it isn't perfect it works. Also, if I tune the TC off everything seems to work better and the rev/engaging goes away but still slight shudder through the low end of first and a tiny bit into 2nd....

any input I can get before I start shopping around is appreciated. If I can just fix a specific part in liu of an entire rebuild that would save me some loot.....also, if anyone knows a good tranny shop in Phoenix let me know....

 

[denalianyone]

Damn, going again!! Hopefullly it is something minor.

 

[Grocery Getter]

Damn, going again!! Hopefullly it is something minor.

You and me both.....

 

[Jay]

Rebuilding 4L60Es are a very hit or miss ordeal... most shops approach them like any other trans but, honestly, it's NOT like any other trans. If you can spare the cash, get a remanufactured unit from GM and either install it yourself or get a trusted shop to do it. GM dealerships will butt-**** you to install it.

Hard to tell what is specifically wrong by description, but it sounds like the sprag is slipping. It'll either be clutch related or hydraulics related (leak in separator plate gasket, check ball, etc). In many cases a shudder will be torque converter clutch related. Here, though, it sounds like it might not be the case.

When you shift manually with the column shifter the only difference is that the overrun clutch engages (giving you engine braking). The overrun clutch can and will make up slack for a slipping sprag. Not sure why turning off traction control makes a difference though, unless the PCM senses slippage and cuts back on power enough to make it feel better.

Have the shop check the sprag. Make sure you have the latest Borg Warner 29 element unit (do not use the cheap 30+ element versions). i personally would get a brand new sprag housing while you're in there, they're cheap and having a good sprag in a bad/worn sprag housing will fail in no time.

Side note:
It's a good practice at the drag strip to launch with the column shifter in "1", shift to "2" when needed, then just before it's time for 3rd gear, shift to "Overdrive" (not drive). The reason is, the sprag takes a beating on the 1-2 shift and having the overrun clutch engaged greatly helps reinforce it during the shift. The reason you want to shift straight from "2" to overdrive right before 3rd gear is due is to kick off the overrun clutch for two reasons: 1) it does not help the 2-3 shift in any way, and 2) it takes away critical line pressure needed to get a solid 2-3 shift (the most vulnerable shift in a 4L60). The overrun clutch will need ~15psi or so of line pressure at max to keep the overrun engaged, and that's too much lost pressure for the 3-4 clutch to live.

 

[Grocery Getter]

Thank you for the info! The sprag is what went last time and I had it upgraded. The rebuild was out of warranty by about 7K so the shop compromised and I am only paying for parts. I was supposed to drop it off Monday and was driving it very gingerly just to/from work but it didn't make it.....on Thursday I lost everything and I could only go about 10mph@5K rpm in 1st but when I got it going enough to catch 3rd I was able to limp to work and get it towed to the shop. I had no 1st, 2nd, and 3rd slipped in and out. They won't get started on it until Monday so we will see...........

 

[blueflamed03]

rebuilding locally again, or buying one already beefed up?

 

[04SS99Denali]

im actually having the same exact issue with my yukon its just not as bad as what you have stated. it will just jerk a little and its off. it does it about once every 5 times i take off. if i floor it from a stop it seems to engage perfectly. every other gear shifts like glass. i plan to get it rebuilt in a little once money permits

 

[Grocery Getter]

rebuilding locally again, or buying one already beefed up?

Since the same garage is covering the labor since it's just out of warranty I am giving them another shot, I just have to pay for parts/fluid. It's going to end up costing me about $300 and $130 of that is the RP ATF fluid..... as of now I think I am just looking at a new ZPak and paper/gasket kit or at least I hope that the clutches just burned up for some reason..... The sprag was upgraded last time so that "should" be good....... my lat tranny went out with a HUGE BANG....this time it just started losing gears gradually.....so I am hoping no major parts are needed.......

 

[Joe1129uscg]

I replaced mine with a unit from Monster Transmission. $1500 shipped to my door, 2 hour install.

 

[blueflamed03]

GL bro...hope it all works out good for ya!