Any way to validate a tranny without driving it?, Seems tight...but? Options

[Cheapsnake]

Yeah, I know, rebuild it and be sure. That would make sense if I had the patience to do it, but I'm looking at hooking my 901 up to a Rover 3.5 V8 tomorrow and I'd like to do at least a cursory evaluation on it before I commit it to the engine. It came off my project car and I've never driven it so I'm shooting in the dark. I've turned the mainshaft and run it through the gears and everything seems fine, no unusual noises or catches. That makes me feel good but I know that's not a reliable indicator of a good tranny.

Anybody got any static tests or spec's I can check to verify this thing?

Tom

[ChrisFoley]

There's no way to properly check the synchros without either disassembling or driving it. Some obvious defects can be felt just by engaging each gear from the shift selector on the console, but worn synchro teeth probably won't be felt unless they completely refuse to engage.
One item that often needs replacement is also one of the most expensive - the 1st/reverse slider.
You can pretty much count on that, the 1st gear synchro hub and the 1st & 2nd gear synchro bands all being worn out in any well used box that has never been apart. Those 4 items will cost about $700.

[Cheapsnake]

There's no way to properly check the synchros without either disassembling or driving it. Some obvious defects can be felt just by engaging each gear from the shift selector on the console, but worn synchro teeth probably won't be felt unless they completely refuse to engage.
One item that often needs replacement is also one of the most expensive - the 1st/reverse slider.
You can pretty much count on that, the 1st gear synchro hub and the 1st & 2nd gear synchro bands all being worn out in any well used box that has never been apart. Those 4 items will cost about $700.

Thanks Chris, I was dreading those words, but probably quite realistic. Lacking a Dr. Evil in the house, is there any good publication on rebuilding these things?


Tom

[Mark Henry]

Look in the classic threads section and a manual helps, not as hard as you think, you just have to get your brain around it.

Chris's parts prices are correct for new, but you can often find good used.
If you have 2 trans you might be able to make one good one. It's worth investing in a 2nd core trans for when you do the build.

Evil's tranny clinic I had 4 cores, I got 2 rebuilt trans and enough parts to build a 3rd, which will be the 911 tranny for my bug.

[ChrisFoley]

is there any good publication on rebuilding these things?

I think the Haynes 914 Manual has enough info to tacke the basics.
I used a Factory Repair Manual for my training, and tore a bunch of boxes apart to get the hang of it.
Replacing synchro hubs takes some special tools, but you can send the gear out to have it done.
Any operation on 2nd to 5th requires a plate that supports the roller bearings while the stack is unbolted.
Changing the first/reverse parts can be done with the gearstack installed in the case.

There are a couple of easy inspections that don't require any special tools or training:
The first thing I suggest doing is drain the gear oil and check the drain plug to see now much metal shavings are on the magnet. If its fairly clean, just re-fill the box with fresh Swepco and run it.
Another thing you could do while the box is drained is remove the rear cover, unbolt the 1st/reverse shift fork, remove the slider to inspect the teeth for wear and have a good look at the first gear synchro.
Before loosening the fork bolt, carefully mark the position (both linear and rotational) with a Sharpie so you can put it back exactly where it was.
Also you have to be careful with the idler gear assembly which is loosely supported on a short shaft on the rear cover.

[r_towle]

DNHunt did a great pictoral of how to tear it down and replace the parts...then put it all back.

Its really not that hard. It is easier than a motor.
The hard part, like Chris said, is getting the hubs off the gears...
You can just decide what needs to be done and send them out....
It can also be done with simple tools if your handy.

Rich

[ChrisFoley]

It can also be done with simple tools if your handy.

especially if you don't plan on re-using the hub, lol. (IMG:style_emoticons/default/biggrin.gif)

[jmill]

I wanted to do a clinic up here. I have 2 boxes myself that could use a once over. I asked if there was interest and got no response. With winter on the way my garage space is out. I'm waiting on Dr. Evils's video now unless a guy in WI with a heated garage wants to step up. I've got a spare room for the Doc in Racine. My free airfare connection got laid off.

[burton73]

This ad is on classified now. For $300 it is a good deal if it is true. It is in LA. That is your only problem. The member is -bottomend

Bob

I have a nicely shifting transmission for sale that I have driven myself. It's right at the 100,000 miles mark. I've cleaned it up good (more than when the pics were taken) and it's boxed and ready to ship. I recently had a buyer on the east coat back out and it was going to be $100 to move this from where I am on the west cost via UPS. I'd like not to eat the paypal charge so please factor that in as well. $300 plus shipping.
Thanks ya'll !

[Dr Evil]

Chris and Mark are on the money. If you need links to build threads start with my rebuild link below. I have many links, like DNHunts link, in that thread to help those brave enough to give it a go on their own. I can often get that $700 in parts down to about $300 or so with good used. If I were you here is what I would do:

Remove the rear cone, 1/R slider and inspect

Remove the gear stack, inspect or take pics for us to inspect

You can get a new gasket for between the tail cone and the intermediate plate for $5 from Mikey914 here. I can send you the gaskets for between the intermediate plate and the case if you can get me a sample to measure the thickness. I can talk you through that and the seals from me would be free (I have plenty of spares).

The one thing that may allude you and has been a problem in about 55% of the boxes I have been in this year is a cracked cage on the output shaft bearing in the intermediate plate. This can cause a whine and cause your output shaft to loosen and lose its index. This leads to a quick demise of your box.

For WI, if you book it I will go (IMG:style_emoticons/default/smile.gif)

[McMark]

The one thing that may allude you and has been a problem in about 55% of the boxes I have been in this year is a cracked cage on the output shaft bearing in the intermediate plate.

That's what happened to Fiid's box on the way to RRC 2007. We nursed that thing all the way to Eric's for a quick 'refresh'. (IMG:style_emoticons/default/biggrin.gif) Good times.

[Mark Henry]

The one thing that may allude you and has been a problem in about 55% of the boxes I have been in this year is a cracked cage on the output shaft bearing in the intermediate plate.

That's what happened to Fiid's box on the way to RRC 2007. We nursed that thing all the way to Eric's for a quick 'refresh'. (IMG:style_emoticons/default/biggrin.gif) Good times.

All I was missing from having a 3rd box built.
I'm hoping my 911 box (for my bug) has a good bearing then I'm golden.

That bearing is another pricey Porsche part if you have to buy new.

[Cheapsnake]

Well, it looks like I'll have time to do a thorough inspection after all. Kennedy sent me the wrong flywheel so my plans of mating the tranny are out the window for a couple weeks until I get this thing replaced. (IMG:style_emoticons/default/hissyfit.gif)

However, as I'm fussing and fuming over the screw-up, I noticed that the case has sealant at the joints. The engine was rebuilt by the PO so maybe he did the tranny also? (IMG:style_emoticons/default/piratenanner.gif) Either that or the sealant is from the factory and this thing has never been touched and is a POS. (IMG:style_emoticons/default/hissyfit.gif) It does have fresh lube and the plug is clean. (IMG:style_emoticons/default/piratenanner.gif)

Excuse me while I flip this coin.

Tom

[computers4kids]

I noticed that the case has sealant at the joints.
Tom

Then again, the case has sealant at the joints (IMG:style_emoticons/default/hissyfit.gif) The good Dr. says...NO SEALANT." Then again, if that's all it may be good... (IMG:style_emoticons/default/piratenanner.gif)

[Dr Evil]

If there is sealant then the DAPO left their mark. NO SEALANT, EVER. There is no need for it and it screws up indexes and such. Pull the stack.

Here is a list of things that people do when they do not know what they are doing or dont read the book:

- Sealant
- Install lock washer at end of input shaft upside down thus fouling the threads of the retaining nut
- Over tighten the retaining nut
- Air chisel the bolt on and off of the end of the output shaft, air chisel the retaining nut
- Under tighten the same bolt allowing it to eat through the rear cover
- "Rebuild" the transmission with out indexing the sliders correctly thus causing an early demise of some expensive parts

These are the common issues. There are more exotic ones that I have seen. (IMG:style_emoticons/default/dry.gif)

[tat2dphreak]

one thing I've noticed with mine... it shifts great when cold, never miss a beat... when it gets warm, it gets sloppy. to me this is why you can't validate it without driving a good while.

[Dr Evil]

Wayne, use thicker oil and see if that helps. The tranny does produce heat and the oil becomes pretty thin when warm. Your box sounds tired, though.

[r_towle]

The one thing that may allude you and has been a problem in about 55% of the boxes I have been in this year is a cracked cage on the output shaft bearing in the intermediate plate.

That's what happened to Fiid's box on the way to RRC 2007. We nursed that thing all the way to Eric's for a quick 'refresh'. (IMG:style_emoticons/default/biggrin.gif) Good times.

I found it more like 75% of the time.
Seems to be one of the major weak links.

Rich

[tat2dphreak]

Wayne, use thicker oil and see if that helps. The tranny does produce heat and the oil becomes pretty thin when warm. Your box sounds tired, though.

I'm using valvoline 85w-90 currently. it probably is tired tho. shifts great cold, but when the engine gets warmed up, 2nd gear gets elusive..