checkmate1996

----Updated on 1/26/10--------
Folks,

I am rebuilding my g28-05, and before I drop BIG $$ on parts, I thought I would run it by the 'listers...

A couple of questions, how often does the input bearing need to be replaced, or in other words do it go bad often? Are there tell tale signs, cuz this guy is over 1/3rd of the rebuild alone.

Same question for the engagement teeth. Some say absolutely replace no matter what, others say just replace synchros. Are there tell tale signs to know what to replace on the teeth or how much wear?

Are there any other part recommendations?

Thanks for any and all thoughts!!

Here's my final parts list with a recent price quote if you think your are rebuilding yours...I also rebuilt my TT as a WYAIT item...which is included...YMMV

https://rennlist.com/forums/members/...5partslist.jpg

SharkSkin

I have a NIB input shaft bearing that I bought when I thought I was going to rebuild my trans. I ended up getting a rebuilt so I don't need the bearing. I'll let it go for $375 plus shipping.

I could tell mine needed replacing because I was able to get a dial indicator up through the rear inspection cover and establish that it had significant play, after I tracked a bearing noise to that location with a stethoscope.

Sorry I can't help much with your other questions.

Ben Allison

You'll know pretty readily if the dog teeth are chewed up.

Hardest part of the whole ordeal for me was getting the shift rods out. I'd be curious if there's a better way to do it. Heating up the selector forks only helped a bit.

You'll also need new freeze plugs from where you take the shift rods out of. From PET it looks like it's part number 900.040.013.02 (quantity 3), but it's been so long I can't remember.

900.123.043.30 (quantity 2) - seals for the shift rod detent lock thingies.

900.302.009.00 - you may end up pulling this dowel pin out to help press out of one of the shift rods.
900.309.013.00 (quantity 1) and N.013.017.1 (quantity 7) - new dowel pins for the selector forks, although I ended up just using some from my hardware bin.

900.041.019.01 (quantity 2) - internal circlips on the ends of the layshaft. I have a vague recollection of needing these, but I might have broken one accidentally.

James Bailey

They always need dogs and often a slider or two if you really want it to shift like new ! Anything less is going to be less in more ways than one. The bearing takes a lot of abuse and they do wear out. Good to remember that the grinding you hear with "bad syncros" is not coming from the syncro !

checkmate1996

great tips guys...i appreciate it.

Dave, can you talk about how you got yours rebuilt? I searched rennlist and nobody has talked about that...

If I can't rebuild mine, your offer sounds good...

brad

SharkSkin

Brad, I got mine through 928 International. 3 guesses who actually wrenches on 'em.

928worldwide

Brad,
I have the internals from an '82 ( I sold the lsd). The reverse gear has some chipped teeth that were making noise- so the PO took apart to repair... and then sold to me. The rest of the functionality was perfect according to the PO. Unlike the last gearbox, i DID NOT drive this one.

The Parts you need would be my pleasure to provide;
All of the synchros , gears, and whatever else you need...You can have for 50% off the going rate- It's just taking up space in my shop. I'll make you a package price you can't refuse for all of the stuff you don't need to buy new.
Here you have a straightforward fantastic deal that you can do nothing but smile about. I'll take photos of all before shipment so you can see if any look undesirable. It's clean as a whistle and the frags from the R gear didn't appear to cause any damages at all.

checkmate1996

Mason, thanks so much for the offer. However, I want this operation to be a one time deal, so I do want to replace all the dog teeth, etc new. I'd hate to get it all back in to find out something else needed to be replaced. That would be a PITA! The only thing that I *might* be interested in would be the main input bearing and it's condition...

Dave, I misunderstood, I thought you meant you had your main input bearing 'rebuilt' somehow...

I will be having the entire transmission rebuilt...

SharkSkin

No, I have a new input shaft bearing that I bought back when I was thinking that I would have my original transmission rebuilt. It was not needed when I went the route of doing a core-exchange rebuild through 928 international, so now it's collecting dust. If you want to save a few bucks let's talk. If you're doing a core exchange type of deal you won't need it.

checkmate1996

Dave, I got you on standby...

Thanks for the offer...

checkmate1996

A quick update -

I also needed a new countershaft and the 4 needle bearings that go on the countershaft. The four needle bearings were extremely pitted causing it to actually make grooves in the countershaft. My mechanic thinks this may have been a contributing factor to the 'whining sound' I would hear as I would progress through the gears.

checkmate1996

I got everything back but my mechanic said the dog teeth were a bear to replace and he also found a out whomever was in the box before didn't replace a key snapring on the countershaft...uggh!!!

Well..atleast it's back in my posession and ready to be installed...here's to making SITM 2010!!!!

I also updated the first post to reflect what I actually replaced and current pricing..

SharkSkin

Wow... plus labor... it better work fantastic!

checkmate1996

AMEN Brother!

Imo000

I've heard form a local 928 owner that the worn dog teeth can be turned slightly modified and turned around for re sue. He did this on his '83 years go and even with regular track use, it still performs flawlessly. Also if you decide to rebuilt the TT bearings, the OEM bearings are less than $20 each as opposed to the ones you listed. If the originals laster +20 years, the replacements should too. These two items alone should save you a chuck of change.

If you are interested, I can find out more details on this. He's a lister but rarely posts here.