Parts advice for rebuilding my 4L60E trans in the Denali

[Bow_Tied]

Hi Folks,

Looks like I am in for a trans rebuild and will be having a local specialty trans shop do the work. Looking for any advice you might have on the parts that should be replaced, even if not broken, for maximum future reliability. Besides what is believed to be a failure of the forward sprag, the shop has indicated that all parts not in spec would be replaced, the rest reused with the exception of the torque converter which would be replaced. I hoping to get a heavy duty sun shell if such a thing is available. This shop is not a shop that will do modifications but I could talk them into replacing certain parts probably.

Also, what about a shift kit? If it matters I tow a reasonably heavy travel trailer with my 5.3L SWB Denali.

Thanks for any advice.
Ron

 

[Denali n DOO]

there was a thread a short while ago, wish I could remember who's post it was. he basically said he wish people would do preventive maintenance on a transmission instead of waiting for it to die. I think the parts he talked about were a new separator plate, vette servo and other thing was... honestly I can't remember but it had a long acronym.

 

[mrrsm]

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[Bow_Tied]

there was a thread a short while ago, wish I could remember who's post it was. he basically said he wish people would do preventive maintenance on a transmission instead of waiting for it to die. I think the parts he talked about were a new separator plate, vette servo and other thing was... honestly I can't remember but it had a long acronym.

@Denali n DOO - If you think of it please let me know. I have scanned all 31 pages in this subform looking at any threads that seemed relevant by the title. Maybe I missed it.

As to maintenance, other than refitting it before it broke I don't know what I else I could have done to prevent this. :/

 

[mrrsm]

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[Denali n DOO]

@Denali n DOO - If you think of it please let me know. I have scanned all 31 pages in this subform looking at any threads that seemed relevant by the title. Maybe I missed it.

As to maintenance, other than refitting it before it broke I don't know what I else I could have done to prevent this. :/

I think the other preferred item was a shift kit that contained a TCC PWM eliminator valve. some info in this thread and a few thread links in that thread. Might have been @gmcman or @BlazingTrails that recommended to use certain items to beef up a 4L60e.

http://gmtnation.com/forums/threads/engine-speed-blips-around-at-45-60mph.13731/

 

[Mooseman]

Shift kit which has all the goodies mentioned:
http://www.ebay.com/itm/270874884435?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

I do believe that sun shells were improved on later years so it should be replaced regardless of condition.

 

[Bow_Tied]

Thanks all.

I don't think this item attached can be found here on the GMT Nation Forums... but it will let you leaf through the booklet on the subject of pre-failure diagnostics and then on to how they are re-built:

http://www.4l60eguide.com/4l60e-transmission-rebuild/

Awesome! That will come in handy.


So far beside the assumed broken sprag and any other worn parts not in the master rebuild kit I should get:
new sunshell
new separator plate
corvette servo

I am not sure about the shift kit. When I initially asked about that at the shop they seemed hesitant, he more or less said "I get complaints when peoples' wives don't like how hard it shifts..." The Envoy is my wife's daily driver, so I need to be considerate about that. Is there a really mild shift kit that is worthwhile? The point may be moot - I will have to see what they will warranty first.

How does one specify the vette servo? Or would any competent shop just know of this?

 

[Denali n DOO]

Here's some details on the vette servo from another site. I'd think the shop would know what it is.
http://www.gmfullsize.com/threads/the-corvette-servo-thread-to-end-all-threads.121944/

 

[Bow_Tied]

Dropped it off this morning, waiting for the call on the assessment. They tried to talk me out of the vette servo idea as they have had a number of customer's wives complain about the shift firmness. :/

 

[AtlWrk]

FWIW, the corvette servo is (mostly) accessible from the outside so if you/your wife hates it, it can always be taken out without dropping or opening the transmission. Not saying it's an easy or fun job but it can be done in the driveway. Just make sure they give you your old one back.

 

[Mooseman]

Copy that for the shift kit but I would recommend the TCC PWM eliminator kit.

 

[BlazingTrails]

The parts I recommend to upgrade is the 1-2 and 3-4 accumulators, and the forward piston. They have a pinless upgrade kit with billet parts for about $40 for that entire kit.

The corvette servo is a must, if the wife don't like it at first she will get used to it later. If you are on the stock tune these parts will likely not be very noticeable but maintains the proper pressure on the clutch packs. These parts will also give your transmission a longer life. And if you disable torque management completely you will be better off.

Don't forget an auxillary cooler whether you tow or not, the cooler your transmission.......the longer it lives.

 

[Bow_Tied]

Thanks folks. My options were limited in that I needed the rig back up and running as soon as possible for family duty. They had my rig all day Thursday and Friday and I picked it up at the end of the day Friday, they had just finished.

I do already have a good plate style external cooler and I monitor my trans temp with my ScangaugeII.

I got the vette servo, hardened separator plate, pinless accumulators and hardened shun shell at least. This shop has a great reputation but doesn't get too involved in modifications, I had to persuade to get this much. They used dex VI.

My shifter cable had a lot of deterioration to the outer sheath (photo 2a), it was split open and quite brittle (heat damage or just age?). They talked me into replacing it, expensive little cable set.

The sprag was definetly fragged (photos 3a & 4a). I still don't really know what caused this. I don't tow in the winter, just camping once a month june to sept, where I always used 3rd, monitored my temps, already had a cooler etc.) and if it were damaged from towing I'd have expected the 3-4 clutches to fail instead.

The shop reported that my trans fluid was quite burnt which surprised me as I checked the fluid at the time of the incident and it was perfect (dealer serviced last summer). Apparently driving the short distance I did on the, I think they are called the over-run clutches, was quite hard on it as those clutches are not designed for that. And I was wearing through them fast, heavy wear. (photo 1)

 

[moneypit]

Holy chit! I bet ours is like that or worse havent done anything yet but park it out back......Mines an 02 ext-4.2 4wd.

 

[seanpooh]

I should of seen this earlier, I would have recommended the Sonnax Performance HP-4L60E, Super 2nd and 4th servos.

I already had the beast sunshell installed before, the kit included rubber check balls that replaces the steel and something else that fixes the overdrive flutter. And the servos really put a firm shift on upshifting.

 

[DocBrown]

Probably too late now, but there are several separator plates available as well as templates for drilling holes to vary the shift hardness. When I did mine in my old TB the kit and plate I used was a more mild one and it shifted firm but not hard unless I really jumped on the gas. It was a great upgrade.

 

[gmcman]

and other thing was... honestly I can't remember but it had a long acronym.

Was it the Sonnax Super Hold Servo?

It goes in the same time as the vette servo.

Sorry but I saw this thread late.