4HP22 torque converter seating question

[Dash01]

When seating the 4HP22 torque converter to an M30 535ia engine, I turned the TC by hand until it slipped into what seemed to be proper place. With the tranny in neutral, it would spin on its shaft. No leakage.

I placed the TC so one of its 3 nut fittings would be opposite the access hole (right side, lower) on the engine block.

Then, bolted the engine to the tranny. Engine snugged up against the tranny bell housing flange in symmetric fashion (flange surfaces parallel), with only a slight gap. So far, so good, apparently, and flange bolts went in smoothly.

Then, as engine was set at TDC, I noticed that although the engine access hole and one of the 3 the torque converter nuts may have been aligned, none of the flywheel holes were in the same alignment due to TDC engine placement. (gotta have TC nut, flywheel hole, and access hole all lined up to insert the bolt)

Turned the engine, thinking the flywheel triangle plate should be slightly and sufficiently clear of the TC nut fittings to allow non-binding rotation. It wasn't, but instead was binding. So, I had to slacken the bell housing flange bolts to create a small (~2-3mm) gap between bellhousing and engine block, thus allowing the flywheel triangle plate to clear the TC nut fittings for alignment. Then installed 3 flywheel/TC bolts, then tightened the bellhousing/engine flange bolts.

Having read horror stories of improperly seated TCs that destroy transmissions on startup, I'm worried. Various sources say there should be some (~2mm) end float between the properly seated TC and the flywheel triangle plate, lest aft pressure from the triangle plate damage the transmission pump or seals. The TC seemed properly seated, but before I start this sucker up, it seems prudent to ask for insight and advice.

Your thoughts on how to proceed?

Is there any way to check for proper TC seating without removing the engine from the car?

[shogun]

this is for a Landrover 4HP22-24
http://www.bimmerboard.com/forums/posts/697900

[Dash01]

Thanks very much, Shogun.

Looking at the rear side of the TC, it has a shiny shaft with notches in the end, like notches in an arrow shaft to fit the bow string. These female notches are square and about ~10mm deep and fit corresponding male tabs on the internal transmission pump. So, when seating the TC, either the notches match the pump and the TC slides all the way back, or it doesn't. Is this correct?

But, other information says that when the bell housing and engine block flanges are fitted together, there should be ~2mm between the TC nut fittings and the triangular flywheel drive plate. If I understand correctly, the TC should be able to slide back and forth ~2mm before the bolts are installed and tightened. Is this correct?

Bentley says the triangular drive plate has indentations to fit the TC nut fittings, but my drive plate is flat with no indentations.

If my TC was not fully seated, then I assume its shaft notches would not have fit into the pump tabs, making the TC stand out ~10mm (notch depth), and making a ~10mm gap between engine block and bell housing flanges. My flanges came together OK, with no such gap. From this, is it safe to assume my TC was properly seated?

Transmission fluid: None drained out of mine, which was kept with the shaft in level (horizontal) position. Since none drained out, I didn't put any more in. Was that correct? And, if the fluid is low in the TC, is that replenished from the hollow central shaft from the transmission?

[ryan roopnarine]

i really doubt that 2mm is sufficient on any transmission, especially since you are complaining about binding. disclaimer: i've never done a 4hp22. try to turn the engine from the crank bolt. if you notice ANY unusual tension compared to when you took it apart, back the housing out as much as you can and disconnect flywheel/tc. on my 4l30e i had this problem. i only spun the tc until it made the first engagement or "drop" towards the tranny case. i found afterward that the tc engages the shaft in two stages. the first set of spins gets it down, but not enough. i had to spin it some more after the initial engagement to get it to finally seat. i don't think you should have to engage in any bellhousing antics to be able to rotate the tc to get it to align to the flexplate, simply turning the tc with your finger through the access slit and rotating the engine with a wrench should get the job done.

[Dash01]

Ryan, setting aside your caveat about not having worked on this particular tranny, and assuming it to be essentially the same as yours:

You mention a two stage seating sequence, where the TC goes mostly into place with the first spin, then seats a bit further in with more spinning. I've read from other sources about getting that second click. How much further into the tranny housing comes with a second click? How much more spinning of the TC is needed to get this?

And, if turning the engine by hand (in clockwise direction as seen looking rearward) by the big nut at the front, with the drive plate bolted to the TC, why wouldn't this action serve to do the final spinning of the TC into its second-click seated position? In other words, would turning the coupled engine/TC by hand be sufficient, without needing to pull the engine/tranny apart for further hand-turning of the TC for final seating?

[ryan roopnarine]

Ryan, setting aside your caveat about not having worked on this particular tranny, and assuming it to be essentially the same as yours:

You mention a two stage seating sequence, where the TC goes mostly into place with the first spin, then seats a bit further in with more spinning. I've read from other sources about getting that second click. How much further into the tranny housing comes with a second click? How much more spinning of the TC is needed to get this?

And, if turning the engine by hand (in clockwise direction as seen looking rearward) by the big nut at the front, with the drive plate bolted to the TC, why wouldn't this action serve to do the final spinning of the TC into its second-click seated position? In other words, would turning the coupled engine/TC by hand be sufficient, without needing to pull the engine/tranny apart for further hand-turning of the TC for final seating?

1) further in the second click...--It goes in a rather significant amount from engagement 1 to engagement 2. i'd approximate that it goes in the same distance from "free" to 1 as it does from 1 to 2.

2) turning the engine by hand...I don't have an official technical reason for what i'm about to say, but, from my observations, i'd say that engagement 2 is the only depth in which there is significant enough depth for the torque converter to "press in" and ride on the flywheel rather than ram itself against the flywheel. remember, the tq converter bolts are only required to be torqued to about 17lbft (on my transmission, i don't know what yours is). it is kind of paradoxical--the torque converter only needs to "ride" on the flywheel somewhat to transmit power, rather than be extraordinarly snug.

as for spinning the engine now--no, because (in my limited experience) if the torque converter is ramming the engine and preventing it from turning easily, it has likely gone in at an angle (however minute

engine->| \ <-torque converter
| \
| \

because of the nature of how you put the transmission in to position.

if you are really lucky, and you know for a fact that there is a second engagement on your particular transmission, i'd back the transmission out as far as the bolts will let it, until you can spin the tq converter with your fingers, and spin that sob for a solid minute or so (while pressing down on the converter with your other hand). you should get a good deal of excess space after you do this. if nobody else with hp22 experience chimes in, please fell free to pm me.

[ryan roopnarine]

glad to be of help, if i was. i am happy to be able to save someone else the PITA of trying to mount their tranny wrong and possibly save a pump (unlike someone i know that had to take it all apart again and only figured out what was wrong when they reseated it separate from the car.....)


oh, and PS
good luck with the rest of the work that you have ahead of you getting your 3800lb paperweight moving again.

[Dash01]

Thanks Ryan. BTW, the most useful single piece of information that helped me was your observation that seating the TC is is two stage process. At a glance, one can see that the TC has those notches in its aft shaft, and that such would fit corresponding tabs on the tranny. What is not described in any literature that I found, however, is the two-stage process of fitment, leaving me working with the misconception that I'd properly seated the TC after only the first stage. Without your comments, I'd still be under the damn car in the driveway, teaching the neighborhood kids some new vocabulary my wife calls "Car Talk."


Glitches to note: 1.) Various printed sources describe the triangular drive plate as having indentations where the 3 bolts go through. My drive plate has no such indentations, but instead is completely flat. 2.) Shogun's excellent factory literature has a long list showing the dimensional inset of the TC on various ZF transmissions, which range from 22mm upward. In other words, the TC inset list refers to the depth of the geometric plane intersecting the TC nuts from the geometric plane of the bellhousing flange. So, depending on the number cast onto the upper left side of the tranny case, a given TC may be inset from the plane of the bellhousing flange by quite a bit. My tranny number does not appear on the printed list. Bentley E34 book makes no mention of this, other than to say the TC nuts should be inset from said flange plane. Best to keep in mind, however, that every tranny shown on that list has some TC inset. 3.) If separating tranny from engine, BMW has a special tool to keep the TC from sliding out from its seating and causing re-seating problems. Duct tape would probably work great for this.

[whiskychaser]

Thats some damn good information! I'd just add that you need the flat of the triangle on the flex plate at the top and stick something in one of the TC holes to line it up with the hole in the bellhousing - the stub of a pencil will do! When installing the tranny, I use a bit of threaded bar with a couple of nuts on to clamp to the edges of the bellhousing. That holds the TC in place until the gap between the bellhousing and engine is about 1/2" when it is removed.

[Dash01]

Thats some damn good information! I'd just add that you need the flat of the triangle on the flex plate at the top and stick something in one of the TC holes to line it up with the hole in the bellhousing - the stub of a pencil will do! When installing the tranny, I use a bit of threaded bar with a couple of nuts on to clamp to the edges of the bellhousing. That holds the TC in place until the gap between the bellhousing and engine is about 1/2" when it is removed.

Good point, Whiskey. Here's another little tip: Magnetize your 17mm socket so the three 17mm bolts that attach the drive plate to the TC will not fall down to the bottom of the bell housing. When it does, it'll be on the wrong (forward) side of the flywheel, without enough space to get it out of the 2"X3" inspection hole at the bottom. In such event, plan on using a magnet on a stick or string, aided by some good vocabulary.

Otherwise, I used an old Bic pen as an alignment dowel.

Another idea to keep the 17mm bolt from falling down would be to use a thin-wall sleeve or channel made of perhaps an old plastic bottle, to place under the bolt/socket wrench and catch the little bugger before it falls. Or, maybe tie a thread to the 17mm bolt shaft and tie the other end someplace secure, until the little bastard is properly engaged on the TC nut. These wonderful thoughts somehow came to me just after I just crawled out from under the goddamned car in the rain, fishing that little sucker out. You knew that.