Differentials aren't supposed to look like this

"Jake - Has Bad Luck So You Don't Have To" (murdersofa)
04/13/2016 at 09:29 • Filed to: None

Hanging out with Zeph last night and the Park Avenue Ultra we were driving around in had some issues. Namely: Park would only engage some of the time, there was an odd noise coming from the trans, and it would occasionally shift REALLY hard without setting a P1411. After driving it for a while it also started not shifting out of first until 4000rpm. After putting the V12 S600 back together and freeing up the lift we got the PAU on it and lifted it up, popped the ball joint, and pulled out the diff. This is what we saw. The diff somehow had walked outboard towards the outside of the car, letting the parking pawl slip between the gear it engages on and the diff leading to it not always locking up. The pawl chipped away most of the corners of the teeth it engages on, and that slurry had found its way between the pawl gear and the transmission case (I really don’t know the technical terms for this shit) and became a lathe removing an enormous chunk of material from that gear. We then dropped the pan and found a pile of metal about two inches in diameter and an inch high which contained the remains of the diff gears and pawl gear, then pulled the filter which was so clogged with metal bits that it was actually fairly heavy.

This car was drivable before we put it on the lift.

How the hell.

It got even more fun when we noticed that the starter motor mount was totally broken, and after engaging and starting the engine the starter would swing down (!!) and slam into the trans coolant lines, one of which was completely pinched off, both of which needed to be replaced along with the starter.

We’re going to clean it out, toss in a new filter and fluid and a new diff, ghetto the parking pawl, and call it a day cuz we’re fairly certain this car is haunted.

DISCUSSION (14)

Daily Drives a Dragon - One Last Lap > Jake - Has Bad Luck So You Don't Have To
04/13/2016 at 09:39

I’m impressed that it still moved under its own power.

DrJohannVegas > Jake - Has Bad Luck So You Don't Have To
04/13/2016 at 09:40

How the hell.

Somewhere in Metro Detroit, an old GM transmission engineer is chuckling softly to him/herself.

MontegoMan562 is a Capri RS Owner > DrJohannVegas
04/13/2016 at 09:42

Absolutely THIS

Jake - Has Bad Luck So You Don't Have To > DrJohannVegas
04/13/2016 at 09:43

4T65e-HDs are fucking garbage transaxle. Source: My Riviera has a 4T65E-HD and it’s a goddamn basket case and I’m shoving 40 less horsepower through it.

Group B Enthusiast - Captain of the supercharged barge > Jake - Has Bad Luck So You Don't Have To
04/13/2016 at 09:44

I also have a Park Ave Ultra that I’m now convinced is haunted... It’s had trans issues for a while, and it never runs right, but last week after I rotated all the tires (one has a slow-ish leak), ALL the tires now have slow leaks... And to top it off, the day after I finished putting the OE stereo system back in it, it decided that the engine should no longer receive fuel. Not sure if it’s the pump, filter, or electrics, but after sitting beached in front of my house for a week, it started right up and now refuses to play CD’s, and won’t give me back the White Stripes album I loaded in it....

Gonna put it on a flatbed and take it to the shop tomorrow. If they can revive it, I’m naming it Christine. XD

DrJohannVegas > Jake - Has Bad Luck So You Don't Have To
04/13/2016 at 09:54

Eppur si muove.

crowmolly > Group B Enthusiast - Captain of the supercharged barge
04/13/2016 at 09:57

Supercharged? Does is have the fuel pump resistor the GTPs had?

Group B Enthusiast - Captain of the supercharged barge > crowmolly
04/13/2016 at 10:10

Yeah, it’s the supercharged Series II (L67). Idk about the GTP resistors. lol

themanwithsauce - has as many vehicles as job titles > Jake - Has Bad Luck So You Don't Have To
04/13/2016 at 10:11

Nah, the 4T65-HD is a pretty damn good transaxle, it sounds like your starter motor pinching the coolant lines did the real damage. Also if the fluid was old and is now old + hot you have more friction. Then parts go ping pong and THEN things finally break.. Punks with GTPs run 400+hp through a standard 4t65 and wonder why they explode but if you aren’t a moron, these things can normally do 200-250k no problem. Even on a supercharged application.

crowmolly > Group B Enthusiast - Captain of the supercharged barge
04/13/2016 at 10:22

GTPs had a fuel pump resistor for handling the high-low circuits and they are/were notorious for failing and leaving you stuck. If they cool down sometimes they work again.

Just a heads up I guess?

Group B Enthusiast - Captain of the supercharged barge > crowmolly
04/13/2016 at 10:25

Interesting! That’s actually really helpful because it’s been running fine through the rev range when it’s cold, but as soon as it gets to temp, it misfires above 35% throttle... And now it’s only working intermittently.

Thanks!

Jake - Has Bad Luck So You Don't Have To > themanwithsauce - has as many vehicles as job titles
04/13/2016 at 12:01

“Oh hello there, I’m the EPC solenoid and I’m gonna fuck up every 140k miles! If you don’t notice that I’ve failed I will trash your torque converter clutch and input shaft!”

So. Damn. Annoying. This is what’s happened on my 4T65e-HD. EPC solenoid went bad, owners didn’t notice, car’s been driving with the trans at max line pressure for god knows how many years which, from what I’ve read, shoves the torque converter outwards a bit which trashes the TCC solenoid and causes abnormal friction in the input shaft. The result? My TCC gets stuck, throwing a code, my trans goes into limp mode, throwing a code, and there’s a noise from my input shaft slowly turning into metal slurry, which doesn’t throw a code.

So now I need a new trans, and I’m considering just tossing in a 4T80e from a Northstar car. Some slight massaging of the engine block and it bolts right up, then I just have to invert the signals going to the shift solenoids since the positions are reversed relative to the 4T65e. With a 4T80e I’ll also be able to do 0-60 entirely in first gear.

themanwithsauce - has as many vehicles as job titles > Jake - Has Bad Luck So You Don't Have To
04/13/2016 at 12:46

Oooooooooor you could just get another 4T65-HD and be fine. The 4T80, while capable of handling the power, isn’t really any better, IMO. The 4T80 is actually older than a 4t65-HD in terms of design. Okay, you need to make sure you don’t lose a solenoid again if you et a new one. Sounds a hell of a lot safer and easier than “massaging the block” and having to splice up the wiring a bit. My old Riv was on the 4t65-HD with well over 250k and even beating on it on woodward it worked really damn well. You have a car that wasn’t maintained properly and the part failed. Don’t mistake that for poor design. Granted, GM transmissions aren’t the best in the world, but it isn’t the part’s fault the PO didn’t care.

Also, side note, I thought in those cars the transmission warning was the gear indicators on the dash would flash to warn you there was a fault in the transmission. Could be wrong, but my riviera did that when I got it and so we changed the fluid and filter and the dust had become a small clump because it sat for so long it restricted fluid flow or something. Or maybe we replaced a part? This was quite a few years ago and most of my issues revolved around the fuel pump but I want to say the 4T65 DOES warn you when things go wrong.

Jake - Has Bad Luck So You Don't Have To > themanwithsauce - has as many vehicles as job titles
04/13/2016 at 14:10

...have you met me? Path of most resistance, bro