Tranny help - stripped/broken drain plug

[JamesInSJ]

Just tackling this job this morning, and the plastic drain plug is cracked. Whoever designed this thing is stupid, because there is little support actually connecting the sides of the socket piece to the sides of the larger plug. I've already tried wrapping a little tape to enlarge my Allen key socket, pushing a thin blade up next to it to fill the space, and nothing is working. At this point, do I just drill it? I'm doing the drain and pan replacement anyway, so not like I need to salvage anything.

[Sophisticated Redneck]

Just drill it since you are putting in a new pan anyway. Wear gloves and get a cheap drill from harbor freight. Tranny fluid smells like fresh cat urine and doesn't come off for days and will never come off the drill.

[Mr.47]

Take off all but 4 pan bolts leaving one on each corner, place a large catch pan behind it and slowly work the the 2 front most pan bolts, the pan will tilt and pour out the fluids, continue working back and front bolts until pan drops, it will be messy, don’t drill it you’ll risk contaminating your trans with plastic bits. Did you attempt to drain the oil while the transmission is warm/hot?

[turboawd]

How's drilling plastic pan going to contaminate anything? He's throwing the pan away.

[JamesInSJ]

Agreed with drilling not contaminating. Fluid/pan was probably lukewarm at best. Only ran engine about 5 minutes in moving car, getting it up on ramps, and slight warm up since it was 40 degrees outside and car had been sitting all night. By the time I got the dirt covers off it was probably 45+ min later so like I said...lukewarm at best. One of the 6 sides was already cracked before I got there, so apparently somebody tried something with the drain plug before my ownership.

In other news, I only got about 2.5 liters in on the initial fill, and it only took 1 more liter on the warm fill (was 33 degrees C). I even left it running, went through the gear shift and 2000rpm procedure a second time, and checked at fill plug again and got a slow trickle immediately, so seems like current fill was correct. Was expecting closer to 4.5. before closing it up I measured the drain, and indeed it was only about 3.5. Any thoughts?

When I get on a computer, I'll upload pictures of the fill plug from before I drilled it, and also the dirty transmission filter (pic into the hole).

[Mr.47]

Initial fill should be ~3 quarts and total fill with engine running is at 4.5 to 5 quarts.

Did you fill/top off the transmission with the engine running at idle?
Is the trans oil pan leveled?

[JamesInSJ]

Mr 47 - yes to all. Followed all the points from these forums, plus FCPEuro guide. Front end on ramps, rear end raised to level oil pan. XDrive35d, though that shouldn't matter for tranny.

[turboawd]

You should have gotten more fluid in there.

[JamesInSJ]

I agree. I'd be more worried if I got 4.5-5 out and only 3.5 in, but in this case drain & fill are both about 3.5. A good example of why it's always good to keep track of measuring drain on any fluid. Any thoughts on why drain would be so low? I went through fill cycle with warm fluid at idle twice to validate, so seems like the expected amount didn't come out in drain/pan replacement to begin with.

[Mr.47]

Originally Posted by JamesInSJ

I agree. I'd be more worried if I got 4.5-5 out and only 3.5 in, but in this case drain & fill are both about 3.5. A good example of why it's always good to keep track of measuring drain on any fluid. Any thoughts on why drain would be so low? I went through fill cycle with warm fluid at idle twice to validate, so seems like the expected amount didn't come out in drain/pan replacement to begin with.

Did you check the transmission temperature with fill, the 8hp70’s transmission temp initial fill is at 30*C and the maximum allowed fill is 40*C.

https://www.newtis.info/tisv2/a/en/f...ssion/BA0uV3hl

Are you using oil pan from ZF and not from aftermarket?

If you need to all the extra 1.5 quarts in a hurry you could lift the car on the passenger side open the fill plug and add it that way so your not short.

[JamesInSJ]

33 degrees C at fill, ZF pan from FCPEuro. Everything looked identical to stock removed one too.

[turboawd]

And the engine was running as you were filling the fluid??

[JamesInSJ]

Full steps I took...
1) Engine running for ~5 minutes, drove around block just to get a little warmth in fluid (35-40 degree F night/morning)
2) Front end on ramps, brought up rear end on jack/stands to level car
3) Dropped covers (at this point, probably 1 hour after #1 above)
4) Removed drain plug (drilled it). Let drain till just a slow drip. Started removing pan.
5) Replaced pan with new ZF. Visibly identical. O-ring on old pan filter came out with it properly. Lubricated new one and pan/filter/o-ring went onto/into tranny with little effort.
6) Initial cold fill - only 2.5 liters. Gave it a few minutes to ensure I had truly maxed that out.
7) Started car, went through whole tranny shift procedure (D->R->D multiple times, 1->3 3-sec, 1->4 3-sec, 1-each gear hold 10-sec each, 2000rpm rev to fill torque converter and get fluid to temperature. Left engine running at idle.
8) Measured 33 degrees C, ISTA-D
9) Popped fill plug, filled 1 liter. Noted that 3.5 liters is far short of 4.5-5 I was expecting. Waited a few minutes, tried to add more but no go...immediately trickling out.
10) Engine *still* running at idle. Went through entire procedure in #7 above again. Measured fluid at 37 degrees C.
11) Opened fill plug, immediately got slow but continuous trickle of fluid. Closed it up and shut off engine.
12) Measured drained fluid, which I did a pretty good job of capturing all of in my pan. ~3.5 liters, maybe closer to 3.3 - 3.4.
13) Edit: Posted experienced here... ;-)

[Sophisticated Redneck]

Originally Posted by JamesInSJ

Full steps I took...
1) Engine running for ~5 minutes, drove around block just to get a little warmth in fluid (35-40 degree F night/morning)
2) Front end on ramps, brought up rear end on jack/stands to level car
3) Dropped covers (at this point, probably 1 hour after #1 above)
4) Removed drain plug (drilled it). Let drain till just a slow drip. Started removing pan.
5) Replaced pan with new ZF. Visibly identical. O-ring on old pan filter came out with it properly. Lubricated new one and pan/filter/o-ring went onto/into tranny with little effort.
6) Initial cold fill - only 2.5 liters. Gave it a few minutes to ensure I had truly maxed that out.
7) Started car, went through whole tranny shift procedure (D->R->D multiple times, 1->3 3-sec, 1->4 3-sec, 1-each gear hold 10-sec each, 2000rpm rev to fill torque converter and get fluid to temperature. Left engine running at idle.
8) Measured 33 degrees C, ISTA-D
9) Popped fill plug, filled 1 liter. Noted that 3.5 liters is far short of 4.5-5 I was expecting. Waited a few minutes, tried to add more but no go...immediately trickling out.
10) Engine *still* running at idle. Went through entire procedure in #7 above again. Measured fluid at 37 degrees C.
11) Opened fill plug, immediately got slow but continuous trickle of fluid. Closed it up and shut off engine.
12) Measured drained fluid, which I did a pretty good job of capturing all of in my pan. ~3.5 liters, maybe closer to 3.3 - 3.4.
13) Edit: Posted experienced here... ;-)

looks like you did everything right, I am at a loss why you only got 3.5 in. I would email ZF with your exact Transmission code stamped on the side and see what they have to say.

[JamesInSJ]

Thanks for all the input. I'm just as concerned with the opposing question...why did only 3.5 liters drain. I'll contact ZF and see what they say on the matter. I'm sure they'll want the code on it too...just what I want to do is raise the rig again and open that cover to get it.

[JamesInSJ]

VF responses...

"May only have drained 3.5L because the converter, clutches and VB (?) were holding a lot of fluid. Might have a leak as well <I don't> which resulted in the lower than anticipated quantity. In other cases, it is normal to drain that amount. I wouldn't worry too much about it unless you find a leak."

For the fill...

"Check the fluid one more time. If the cooling system has a thermal bypass valve, it won't fully open until about 175 F. Once the valve opens, the transmission could be up to a liter low. Ideally, you fill the transmission between 30-40C, then drive the vehicle until the thermal bypass opens. Let the transmission cool back down to 30C, and fill until fluid trickles out of the fill plug. The fill procedure is then completed."

So I read this as... to ensure I'm not driving around 1+ liters short, I'll need to get back in there ASAP since it's had enough drive-time to get the engine and transmission hot. Maybe getting the tranny fluid up PAST 40C (or engine up to normal operating temp >80 C) is actually a necessary step that coincides with ensuring fluid gets into all the right places before the final fill. There's also the possibility based on the first part that 3.5L drain/fill is all that was going to happen in my specific case.

I'll let you know what I find on the next check which might be a couple days.

[Sophisticated Redneck]

Originally Posted by JamesInSJ

VF responses...

"May only have drained 3.5L because the converter, clutches and VB (?) were holding a lot of fluid. Might have a leak as well <I don't> which resulted in the lower than anticipated quantity. In other cases, it is normal to drain that amount. I wouldn't worry too much about it unless you find a leak."

For the fill...

"Check the fluid one more time. If the cooling system has a thermal bypass valve, it won't fully open until about 175 F. Once the valve opens, the transmission could be up to a liter low. Ideally, you fill the transmission between 30-40C, then drive the vehicle until the thermal bypass opens. Let the transmission cool back down to 30C, and fill until fluid trickles out of the fill plug. The fill procedure is then completed."

So I read this as... to ensure I'm not driving around 1+ liters short, I'll need to get back in there ASAP since it's had enough drive-time to get the engine and transmission hot. Maybe getting the tranny fluid up PAST 40C (or engine up to normal operating temp >80 C) is actually a necessary step that coincides with ensuring fluid gets into all the right places before the final fill. There's also the possibility based on the first part that 3.5L drain/fill is all that was going to happen in my specific case.

I'll let you know what I find on the next check which might be a couple days.

VB= Valvebody, You can loosen it (dont have to remove) and about another 2 liters will come spilling out, if three come out on yours, that would explain the missing liter. You can get a more complete change that way but its more involved of course. I bet it is the thermostat on the heat exchanger though like they mentioned, it would be interesting to bring it up to operating temp, then let it go back down to the fill temp and see if it is a liter low. Just avoid any steep declines while driving if possible just in case it is a liter low so the pickup at the back of the pan doesn't suck air.

[JamesInSJ]

Well, took it out while monitoring coolant, oil and tranny fluid temps with ISTA, getting it nice and hot. Took tranny fluid to about 55 C. Let it cool with a fan blowing underneath, checked at 40. Started it up and went through gear selection, 2000rpm torque converter, then went underneath at idle and slowly added fluid until it got a good trickle out...took another 700ml. So not too bad, but seems like taking engine (coolant temp) up to normal operating temp (past 80 C) is probably a good step in the process. Still not sure why the measured amount coming out was on the light side, and the extra 700ml back in isn't too bad, but now I'm confident in this fill being correct. Not sure what the best procedure on the drain portion is to get closer to 4.5 - 5 L out on the outset. Maybe do it with at least warm fluid?