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.

[shogun]

check here under transmission
http://www.bmwtechinfo.com/repair/main/481en/index.htm

[Blitzkrieg Bob]

Did you clean the center dowel on the TC that mates into the crank shaft.

If it is all rusty, it will bind as you try to rotate the TC and replace the 3 bolts.

[whiskychaser]

I dont have the same tranny either but like yours my triangular flex plate doesnt have any indentations to take the TC. From what I can gather you only backed off the trany just enough so the captive nuts on the TC cleared the lip on the outside of the flex plate and lined up inside it. My only concern is you dont say if you levered the TC back to make sure it backed out with the tranny. But TBH I dont think 2mm is far enough for the TC to drop off. Provided you just pushed the tranny to close the gap and didnt use bolts to 'help' I doubt any damage is done. IMHO the auto box may be much heavier than a manual but you dont need all the huffing and puffing to fit it

[Dash01]

Thanks Shogun, Ryan, Blitz, and Whiskey! Your comments were right on the money, particularly the parts about two-stage seating of the TC and the proper gap between TC and triangular drive plate. Today I set a gap of ~6mm between tranny and engine flanges, to make plenty of space to rotate the TC back and forth. After some jiggling, it seated another ~6mm, such that when the flanges were re-bolted, it left a float gap of ~2-3mm between drive plate and TC nut tabs, just like Bentley et al say it should be.

Another thought: Per prior suggestions of folks smarter than me, it's vastly easier to remove the engine and tranny as a unit, then separate & rejoin and on the bench. Beats hell out of trying to reconnect those bolts from under the car.