Stiff Shifting

murbanowski · 09:15 PM

Got a real curious problem that I'm hoping one of you folks can help me sort out.
When my 2.2l is cold, the shift is decent (as far as the side shifter will let you be). When it heats up (after ~ 20 min normal street driving) then the shifting becomes very stiff. Considerable effort is required to push/pull into gears.
He's what I've done so far...

1. replaced all bushings
2. replace fluid w/ Swepco tranny oil
3. replace all synchro's (1st was grinding)
4. replace the main bearing (was broken when synchro's changed
5. adjusted clutch (Kennedy Engineering Stage 1) so that I releases early (high in the pedal travel
6. replace short shift kit with stock.

Aside from the shift kit change, none of the changes produced measurable results. I'm now stumped. Anybody got any ideas??

signed,
someone with a sore right arm!!

(aka Martin) pls contact me @ murbanowski@shaw.ca

Joe Ricard · Joe Ricard's Garage

Well as you know the short shift kit will decrease your mechanical advantage of the shift linkage.
However shouldn't be that hard, what is intersting is that it shifts ok when cold. so I would thing it is not something linkage related. Seems more like internal to the transmission.
Never took one on these aprt so I don't really have a clue. But at least you are at the top of the list again.

red-beard · red-beard's Garage

If you replaced all of the synchro's, shifting is going to be stiffer than it used to be. but...

I'd also check your motor and tranny mounts.

When you say the main bearing was broken, was it the smaller one, on top?

James

murbanowski · 07-02-2002, 08:07 AM

I've check both the engine and tranny mounts. The engine ones are OK, the tranny ones look a little tired but otherwise undamaged.

As far which bearings I replaced, they are the ones for the main shaft and are located in the intermediate plate. When we replaced the synchro's on 2-5 gears, this bearing "exploded". The raceways were shattered in four places. The only thing keeping it together was the fact that it was installed and the main shaft was supply enough pressure against the plate to keep it from falling apart.
Kind of make you wonder how many more of these 901's are out there in that condition??? (Hmmmmmmm!)

Anything else I should be checking?

red-beard · red-beard's Garage

That's the pinion bearing at the intermediate plate. It's the smaller one with brass cages for the balls. I have found several shattered cages on the engine side of the differential.

I believe that the cause behind the problem is lack of lubrication. It's the "high" bearing in the case and will loose lubrication first.

One final thing to try is to remove the side shift console (The shift finger assemble). Completely dissaemble it, clean, lubricate and put in a new shaft seal. I have found that every "hidden" area in the tranny has sludge. I found rust in several places on this shaft and used naval jelly to remove it and then polished it with a sand paper cloth.

James

JWest · 07-02-2002, 10:39 AM

Hey James, isn't the higher one in the case the mainshaft? I don't have a pic in front of me but I'm almost positive that the mainshaft is on top and the pinion shaft is below it.

red-beard · red-beard's Garage

Take a look at this diagram:

No. Description

1 Socket head screw (12 point)
2 Washer
3 Clamping plate
4 Supporting plate
5 Drive shaft ball bearing
6 Pinion shaft ball bearing
7 Bushing
8 Bushing
9 Bushing
10 Shaft
11 Washer
12 Intermediate plate

The pinion shaft (coming from the engine) drives the drive shaft (Heading towards the differential).

James

JWest · 07-02-2002, 01:31 PM

Ahh, I see the disconnect - the shaft coming from the engine is called the mainshaft (driveshaft) and the one going to the differential is called the pinion shaft (ring and pinion). You are mixing up the names of the shafts.

The mainshaft is the longer one with second gear machined in.

That diagram has the bearings mis-numbered.

red-beard · red-beard's Garage

Nope. The driveshaft is the one which drives the wheels.

From the Shop Manual tranny book:

red-beard · red-beard's Garage

Side shift tranny:

52 is the Pinion and 53 is the drive shaft.

Shaft Pictures:

Pinion Shaft:

Drive Shaft

James

JWest · 02:10 PM

Sorry, but you are still wrong. Bad translation from German - maybe.

The clutch on a car always connects to the mainshaft (driveshaft is really the wrong word here, anyway), and the pinion gear on the pinion shaft is the one that engages the ring gear.

see this link:
http://www.pelicanparts.com/914/Parts/Transmission/driveshaft_small.htm

and this one:
http://www.pelicanparts.com/914/Parts/Transmission/pinion_shaft_big.htm

Another clue is that there is a mainshaft seal - there is no such thing as a pinion shaft seal. The mainshaft (upper, to the engine) is the only one with a seal. The pinion shaft (to the differential) does not have a seal because it does not exit the case.

red-beard · red-beard's Garage

I'm just copying what the Porsche Manuals and diagrams have in them...

They call the 2 shafts the driveshaft and the Pinion Shaft. No mention of a "mainshaft". According to the diagrams, the top one is referred to as the Pinion and the bottom one the main. If Porsche is wrong, they are consistent through the manuals...

James

murbanowski · 07-02-2002, 05:27 PM

Ok, now that I'm thoroughly impressed, to settle the argument, it was the lower, bigger of the two.

Now about the stiff shifting problem.... any other ideas???

Ron Meier · 07-02-2002, 06:45 PM

Ok, I'm not gonna challage James1 & James2 & Porsche.....,

Other ideas (bad dreams)\

1. gummed up thru body bushing from junk in center well (not likely).
2. Any bearing you may have not replaced? The older bearings could just be worn out and are beginng to "heat up". We burned up a very expensive tranny when one bearing decided to not run smooth anymore. The key was when the driver told me it was beginning to shift hard.
3. Misaligned shifter forks?
4. Misaligned linkage?
5. Clutch not disengaging fully?
6. Lack of lubrication?

If it's getting sluggish when the temp comes up, it's for damn sure something is getting hot and closing up clearances.

I'll crawl back into my cave now

red-beard · red-beard's Garage

Ok, lets end this war! We don't want Wayne banning either of us for just having a discussion. I'm big enough man to admit the Porsch manuals are inconsistent and wrong!

Anyway, they have 3 different names for the drive shaft (Drive, main and input). They call the pinion shaft the drive shaft in a couple of spots. They also have the bearings mis-labled as does Pelican. Boy I'd hate to be Pelican when someone orders the wrong bearing...

James

Peace?

(through superior horsepower....)

red-beard · red-beard's Garage

Ron's Possibilities:

1. gummed up thru body bushing from junk in center well (not likely). Maybe this plus misalingment.

Well, if they are lubed well, maybe, but why when it warms up?

2. Any bearing you may have not replaced? The older bearings could just be worn out and are beginng to "heat up". We burned up a very expensive tranny when one bearing decided to not run smooth anymore. The key was when the driver told me it was beginning to shift hard.

I would think that would affect the upper gears and only 1 pair.

3. Misaligned shifter forks?

Ron, you may have something here...

4. Misaligned linkage?

Possible, and my prime candidate.

5. Clutch not disengaging fully?

With heat. Hmmm. I would think that heat would make the cable tighter.

6. Lack of lubrication

I hope not.....

Wait! Sliders! What do the sliders look like? I cleaned up all of mine with a file in between each slot. If you didn't do this, the clearences could close up. I would think this would affect 1st and 2nd, maybe 3rd, the most. 4th and 5th would be least (that slider is usually in the best shape).

James

murbanowski · 07-02-2002, 09:50 PM

James, you may be on to something there.

There no junk in the firewall for sure. The car is a "ground up" resto with only 1500 km on the speedo.

Last summer the synchro's were changed, along with the now infamous bearing and the short shift kit removed. Same problem.

My wrench who did most of the internal work looked at the sliders and didn't see anything wrong with them. Is there a way to visually inspect them to determine fault? Come to think 4th and 5th seem a little easier than 1-3. I'll have to pay more attention to this on the weekend. ( 4hour round trip to Whistler with the local PCA club)

As far as the shift forks go, he said they all lined up Ok (don't know what form of measurement he used to determine OK).

Lots of swepco so its not dry.

Misaligned linkage?? all seems to be ok when aligning.

Anything else I should pay particular attention to this weekend that would help?

Martin

red-beard · red-beard's Garage

1st is "relatively" easy to inspect, if you remove the back cover.

Hmmm. Maybe you can inspect 2nd/3rd slider through the shift console port. I've never tried. 3rd would be easier than 2nd. You'd shift the slider into the opposite gear and inspect the "backside". 2nd would have to be done with a dental mirror.

If you have access to a boroscope, you definitely could inspect it this way. In fact, you could inspect everything in the tranny.

Hmmm. Maybe I need to invest in one....

James

red-beard · red-beard's Garage

I ask and the Internet delivers...

Borescope for under $300!

http://www.tooldesk.com/shop/borescope1.wml

James

JWest · 07-03-2002, 05:20 AM

Well, I DO want to continue this discussion which I did not consider a war (I am sorry that you did). This is a tech board, and if there is a mistake in the factory manual (which there must be because there is an change in names) I think this is the place to wring it out and document it.

What a great thing to add to your trans tech article! A clarification of a confusion in the manual.

My outlook on this discussion was that we would bring the facts to light (which you have done well with your diagrams you posted) and maybe DD could agree on where the mistake and confusion comes from and then have Wayne correct the Pelican catalog.

The problem with the internet is that we can't see the other person, and don't know their tone when they write something. I intended no ill will toward anyone, especially you as I think you have done an excellent job with your tranny info. I just thought it best to fix something I saw that was wrong.

BTW, I rebuilt my first 901 box 16 years ago and I have done a huge number since then. That is why I feel comfortable with all the parts and confident as to what is what.

--------------------------------------------------------------------------------

It looks like there are some good ideas as to what is causing the warm shifting problem. Unfortunately, unless it is something like the clutch housing being heated by the heat exchanger which could cause the cable to stick to the housing and do funny things to the disengagement (been there), I think this may require a teardown of the trans to find something like James suggested - gummed or burred slider or a misalignment. Do you have a spare trans? Even if it is in bad shape, it would not take too long to throw it in to see if it does the same thing. This could narrow the problem down to outside or inside the transmission.

James (Adams)

P.S. Superior Horsepower? What does that mean? I have a combined 1151 at my house...