Blew up my 2nd Tranny :<

[Z66Modder]

Went to pass a slow box truck after we both made a right turn on 56th street, well I did pass him and quite fast; It was an uphill grade as well. Slowed down to 45 (speed limit is 35) and noticed some smoke in the rearview. Am I starting to burn oil I thought? No it was tranny fluid on the LT header collector. Made it home but the shop says it's toast. This time I'm not modding a standard rebuilt, I'm buying a performance 4L60E from Jegs. Also 3 Year warranty. not 1 year like local shops.

Features:

• Handles Up To 450 HP
• Heavy Duty Sunshell
• Heavy Duty 3-4 Clutch Pack
• New Electronics
• Reman Pump with New Rotor Vane Slide and Stator Support
• Shift Kit
• Corvette Servo
• 0.500 Boost Valve
• Made in the USA

See Here: https://www.jegs.com/i/JEGS+Perform...MIy--6pLyH8gIVlQ6tBh2pUASuEAQYASABEgKhjfD_BwE

 

[ygmn]

Did you look at other performance trannys?

 

[Z66Modder]

Well not really as the truck is my daily. Also the shop wanted $3000 to do the job when they charged $2300 last time. I looked at a lot of standard ones and when I saw this had everything I was needing and at at good price, I just pulled the trigger.

 

[Z66Modder]

So now with a new tranny in there, the small leak that was present on the old one from the driveshaft spline going to the tranny housing is still there. I replaced 2 seals on the old housing after getting a brand new driveshaft assembly. I gave up and just parked facing downhill in my drive so it would not leak out. Fast forward I thought this would stop with a new transmission but it's the same. Could someone with a Z66 please measure that diameter of that spline shaft? diameter of that spline shaft? I'm posting a pic of mine. 1.5" seems about right but not really sure. If it's smaller it would explain a lot. Thanks!

I

 

[Z66Modder]

So now with a new tranny in there, the small leak that was present on the old one from the driveshaft spline going to the tranny housing is still there. I replaced 2 seals on the old housing after getting a brand new driveshaft assembly. I gave up and just parked facing downhill in my drive so it would not leak out. Fast forward I thought this would stop with a new transmission but it's the same. Could someone with a Z66 please measure that diameter of that spline shaft? diameter of that spline shaft? I'm posting a pic of mine. 1.5" seems about right but not really sure. If it's smaller it would explain a lot. Thanks!

Looking at

ACDelco 88963576 Drive Shaft Slip Yoke ​

If this is correct by what a parts site recommends, that shaft is 1.89", this would be why it cannot seal properly.

View attachment 233011 I

Web site list was for 4WD, ACDelco lists this for 2WD and it's 1.59". I really don't know if that is enough to make a difference

ACDelco 19151749 Drive Shaft Slip Yoke​

 

[ygmn]

Check seal PN and specs for what shaft size it seals.
You might be able to find one more suited for your shaft OD.
You know the OD based on housing ID.
Depth aka thickness would be the same.

Also you need to ensure surface is smooth, groove free and nothing to ruin seal.

 

[Raekal]

Looking at

ACDelco 88963576 Drive Shaft Slip Yoke ​

If this is correct by what a parts site recommends, that shaft is 1.89", this would be why it cannot seal properly.

Web site list was for 4WD, ACDelco lists this for 2WD and it's 1.59". I really don't know if that is enough to make a difference View attachment 233012

ACDelco 19151749 Drive Shaft Slip Yoke​

The only difference between a 4wd and 2wd transmission is the output shaft sizing and tail housing. The front end should be identical.

(If anyone reading this has a 2500, the 4l80e rear tail is pressurized with an oil feed tube on the 2wd model, so extra care needs to be taken to seal/ unseal that port if you ever convert one. it's a rare-ish design choice. You'll either leak all over or starve the bearing of oil if it's missed)

 

[MS03 2500]

I think you mean a 4l85e

 

[Raekal]

I think you mean a 4l85e

To be fair, much like a 4l65e, the 4l85e is a beefed up 4l80e. Better components to handle more power. But as far as I can tell there were no tail housing changes, it was just changes to the gear and clutch packs and input shaft size iirc. Though I haven't taken the time to look into greater detail.

Here's a link to an aftermarket part for pictures of the 2wd tail. https://www.reidracing.biz/s80-tailhousing You can see the small tube running to the back to lube the bearing.

It is referred to as the "lube orifice tube". You can find plenty of posts if you search using that term. It's an uncommon design feature that you don't see in many transmissions. I guess GM figured the 2wd tail needed the extra lube for the loads they wanted them to carry. Yet the t-cases as far as I know are the same regardless of load capacity.

Precision transmission (youtube) has a ton of breakdowns on gm transmissions and he does a great job showing how they function. The 4l80e videos will either show where the tubes are meant to go and where the plugs are on a 4wd. 2wd ones will show the full assembly.

 

[Z66Modder]

Thanks guys, some good info here. The more I researched last night the more I realized a $16 seal is much cheaper than a $200 slip yoke. I found one at discount Auto Parts that lists the ID at 1.33". Not sure if that will be too tight. I've seen some as small as 1.03" WTH?. The problem is most sites are not directly listing the seal ID spec.

 

[ygmn]

you need to find the spec page for the seal as it will give a shaft diameter size range and might have various diameters depending on RPM of shaft.

Too tight and it will wear a groove and then leak or may tear or stretch too much.

simple sample of what you can find:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[Raekal]

1996-2013 GM Automatic Transmission Case Extension Output Shaft Seal 24232324 | GMPartsDirect.com

1996-2013 GM part # 24232324 - Automatic Transmission Case Extension Output Shaft Seal

www.gmpartsdirect.com

2002-2006 GM Drive Shaft Slip Yoke 19151749 | GMPartsDirect.com

2002-2006 GM part # 19151749 - Drive Shaft Slip Yoke

www.gmpartsdirect.com

If im not mistaken, i believe these are the parts for your z66. Which like you found out is the 1.59" shaft. Which, yeah, 0.09" is actually a lot of material to be missing when active seals are involved.


Which is kinda contrary to what I had said earlier. I kinda had a derp moment there. Didnt help that most of the ones I was finding showed 4wd compatibility. But I noticed they also omitted 2wd. I wound up finding the same parts at the end. Curious. I should have had my coffee this morning. The 1.89 looks to be the 4wd sizing

 

[Z66Modder]

I took couple pics at lunch of the old seal and yes it does make a big difference. Barely touching in the 1st. I found a direct ACDelco strore 2 mins from work. Checked on 24232324 but no stock in Washington state. Might have to order online. Another thought, if this is for the 1.89" then it won't help me. I will have to find an oversized seal or buy a new yoke.

 

[Z66Modder]

Bingo, found one at Orileys for less than $10.

 

[Z66Modder]

Happy to report the $9.57 Made In America seal fit perfect!! I'll sleep better at night now.

Looking at my 1st pic, it sure doesn't look like a 19 1/2 year old truck.

 

[ygmn]

Did you check how it rides when your tail shaft moves in and out for suspension travel?

DO not want lip to roll but man yes that is CLEAN under there Do you even drive in the rain?

 

[Z66Modder]

Ride was smooth today. It's never garaged and I live in Washington State; so yes it sees a ton of rain every year.