mayday1

After about 18 months of ownership, it is time to separate the tranny from the engine to see what kind of IMSB I have. It is a 1999 with a
factory remanufactured motor installed by the dealer in 2005, so I may have the small single bearing, or a non-replacable big single bearing,
there is only one way to find out. The first engine lasted 45k miles, this engine now also has 45k miles, so I´m getting a bit nervious.

I started this afternoon by first disconnecting the half-shafts so I can get to the bolts in the bell housing. Pelicanś says I should have all 16mm bolts + one 13mm and one triple-square.
Looks like I have 16mm bolts, one 19mm bolt, one 13mm bolt, and one triple-square. I didn´t manage to break any of the bolts free, I´ll need a longer breaker bar I think.

What should be the torque to these bell-housing bolts? Just trying to see if they should be this tight to loosen, or they´ve been red loctited.

Thanks

Noz1974

You can get the porsche technicians manual on disk from eBay for about 30 dollars, it's not like a diy manual it's made to be read by trained techs but I used it along with advice to rebuild my engine.
If the bolts seem tight try some sort of spray release oil , give it a goof spray and leave it to soak for a couple of hours then go steady maybe with a longer bar, be careful not to strip or snap and bolts , it's the worst thing ever!
Not sure of the exact torque but they with be quite tight mating the engine and box is a crucial area!

cds72911

I'm not sure what you'll gain by a visual inspection of the IMS bearing, other than seeing what you'll need to do to replace it. There isn't a whole lot to see once you remove the flange, and very little to no guidance on how to know if the bearing is good or not, unless it is badly physically damaged or worn out to the point of major failure.

What you are doing is a lot of work, and if it is a 2005 engine code reman engine, isn't the general consensus that you should have the newer one that you need to split the cases to replace the bearing?

That being said:

I highly doubt anyone in a professional shop (or even a knowledgeable shadetree) would use red loctite in those bolt positions.

I use a regular 1/2" ratchet, but if you can't break them loose, you could use a breaker bar.

in my experience, getting at the top bolt(s) is easier if you drop the front transmission mount a bit to make some room to work, and approach them with lots of extensions from the front of the transmission.

Bolts aren't measured by the size of the head, pretty sure all of the bolts except that triple square are the same diameter, but have different lengths. The position they are installed in matters a lot. To help with this, I keep a piece of cardboard nearby, mark it for "up" and poke holes in it for the relative position of the proper bolts to make reassembly easier.

You may want to consider some spare bolts in the same metric size to use as guide pins and for reinstallation. Aligning the transmission input shaft and the clutch disk is tricky if you don't do this because of the angles involved and weight of the assembly. It's challenging with the engine/transaxle on the bench, and twice as tricky when it is in the car since you can't see everything. I have used bolts to progressively pull the engine and transmission together once I had things aligned.

Once you remove the IMS flange, make sure you have the correct sealing products to reinstall it. They were mail order for me. Not sure what your local supply house situation is like, but there are sealants that aren't garden variety loctite products. Once you remove those bolts, you need to replace or reseal them, since they are open to the inside of the case. If you're removing the flange, you should consider replacing the flange seal.

If its a manual transmission:
You're taking off a flywheel and clutch, so don't forget new hardware for reinstallation. It is stretch to yield and not meant for reuse.
Inspect the RMS, dual mass flywheel, clutch, clutch input seal, throwout bearing, check for updated clutch arm pivot, IMS flange seal - think about replacing other stuff while you are in there since the labor is about the same, it's just a few more parts.
Consider reinstalling the slave cylinder before reinstalling the transmission. It can be a bear to get right installing it in place with the transmission installed.
Have a clutch disk alignment tool handy.
Insect all of your mounts, the front transmission mount is a lot easier to replace out of the car (unless you have the special aftermarket tool to do it in place).

Last of all, I personally wouldn't do this job without a lift and a transmission jack. I also used an engine holding bar that I fabricated. Could you do it without this stuff? Sure, but I wouldn't want to.

extanker

i think i will follow this one

Slakker

63lbs on all bolts except the one with a nut is 33lbs.

The 996 Torque guide is the best $60 you'll spend if you are going to be wrenching on these much.

https://lnengineering.com/education/...utomobile.html

charlieaf92

I can't believe I haven't heard of this until now. It would have been on my Christmas list.

Slakker

How much can you tell by removing the flange cover? Original vs. retrofit? Single vs Dual vs larger single? Do you need to set to TDC and timing locks just to inspect if you don't remove?

Charlie, lol! Mine is absolutely tattered, black with grease, and the pages have all come loose from the binding. It's so dang handy!

cds72911

I'm no expert, but if I were taking off the IMS flange to inspect the bearing, I'd take the tension off the chains by removing the tensioners, so I'd lock the crank pulley at TDC and lock the cam with a locking bar.

I've got that book too. It's money well spent so you don't have to go digging all over hell to find the specs.

I did this inspection with a used engine I bought, and I can tell you first hand, there isn't a ton to see.

Slakker

This is the boat I'm in.

mayday1

I was under the impression that you can tell whether you have single row, double row, or the larger non-replaceable single row by looking at
the IMSB flange without removing it, no?

The previous owner put in a singlemass lightweight flywheel that I´ve read can be harmful to the engine crank, so I want to replace it with the stock dual-mass
so I don´t get the diesel clatter when idling. Too bad the flywheel and clutch are only 10K miles old, I wonder if I can simply put in a LUK DMFW and keep the
old clutch.

So removing the tranny serves two purposes for me.

Slakker

I don't know of any reason why you couldn't reuse the clutch. I know Jake hates the LWFW but almost all of the SP996 racers use them and don't have any issues with them. That being said, on the street, it's something you either like or you don't.

Montychristo128

If you are replacing the flywheel check out parts geek, they seem to be most cost effective, I used Jason at Warehouse 33 for mine as Parts Geek don't ship to Canada or "PO Boxes", Jason (the nice gent who runs Warehouse 33) reckoned they were below his cost price.

I looked round as I was considering a lightweight flywheel, but went with the DMF as I want the most reliable engine I can build (for the money).

cds72911

I picked up a Sachs clutch kit and a LUK dual mass flywheel - original equipment manufacturers. I ordered them separately from different vendors and saved a couple of hundred $$ over the big name parts houses for the same part.

mayday1

I'll definitely need a DMF flywheel, so will check out the various lower price LUKs. Seems like ebay also sells them a few hundreds cheaper.

I managed to loosen all but the triple-square bolt (dont have a triple square) and the bolts at 12noon and 1oçlock (I cant even see the bolt at 12noon, but I know it is there).
I think these two bolts will be a bear to loosen, any helpful hints would be appreciated. After all bolts are loosen, then it is time to shop for a transmission jack, tools to lock the
flywheel, ...etc. As long as I can get the car back together by Feb I´m happy.

Thanks for all the help you guys have given so far!

cds72911

Get a transmission jack first. You'll use it to remove the bolts. I have a cheap harbor freight version, with the typical coupon it was well under $100 shipped.

Put your transmission jack under the transmission, remove the bolts on the front mount and lower the transmission end down, then go at the top mounting bolts with a 1/2" ratchet and lots (several feet) of extensions, you'll be doing yourself a big favor.

Flywheel bolts aren't hard to remove. You don't need to buy a special flywheel locking tool - you can make one with a short length of steel strap, drill a hole in each end, use an old fastener you removed from the pressure plate to attach one end, and one of the transmission mounting bolts to attach the other end. That'll prevent the assembly from turning.

Reinstalling the flywheel requires a torque wrench and an angle gauge (or a sharpie and good approximation if you are trying to save a buck).

You probably want to pick up (buy/rent/borrow) a tool kit to replace the IMSB - or at least some of the tools: so you can lock the crankshaft and the cams. If you buy the tools separately, make sure you have the right version of the cam locking tool - the 3 chain and 5 chain versions use different locking tools. The LN kit (and copies) have both. If you don't lock the cam and take out the tensioners you could be making trouble for yourself when you remove the flange.

My 2 cents is to buy the right triple square tool, so you don't mess up the fastener. You can get a Lisle kit ( ) at Sears or your local FLAPS or Amazon that has a full set of triple square bits. Or find a good tool truck/Amazon and buy only the one you need.

Oh, and personally, I like to replace bits while I'm in there, so don't forget the aluminum sealing rings & o-rings for the cam chain tensioners; plus a few green cam caps.