Question about super-diffs

Swingaxle or irs?

ALB O: Both are irs.

I have a Rancho Pro Street 3:88 with a Super Diff IRS transaxle.

I have not noticed any vibration or noise that goes away when depressing the clutch above 60mph.

I had a 3’rd gear whine due to a deteriorating countershaft bearing, but that went away when the bearing was replaced.

Have you determined if it is speed (mph) related or Engine RPM related?  

Is the noise there at 60+ mph in third?  

What happens if you’re doing 70+ and then slip it in to neutral, let the clutch out and coast down through 60? (With your foot off of the clutch pedal)

Give us a little more to work with!

The "superdiff" is just an extra pair of spider gears to spread the load on the ring gear. Maybe Danny will chime in with some knowledge about whether the additional spider gears add noise.

I don't think they did in Bridget.

Thanks for the speedy replies. 

I don't know how to distinguish between speed and engine rpm related.  When you have a chance, please elaborate.

Will try the 60+ mph in third and 70+ mph coast in neutral and report back.

Thanks again

Extra spider gears don't add any noise. They aren't turning among themselves when you're going straight.

Noise that goes away when you push the clutch in and noise that is loud on deceleration IS the mainshaft bearing, which is pressed into the gear carrier.

It is possible (I think) to replace without a total teardown, but not easy or likely. I'd like to check the entire thing if it was mine.

At the very least the trans needs to be removed from the car, in a Speedster.

Depending on what year and shafts are in your trans, it could be either a nut or a heavy snap ring holding the shaft to the bearing. The bearing is the big one in this picture WITHOUT the wrench on it. That bearing is supposed to press in the housing and more often than not is the source of noise and steel hair on your drainplug magnet.

Mainshaft on left, pinion shaft on the right. When you push the clutch in, the mainshaft stops spinning.

I’d bet a cup of coffee and donut that what you were hearing is straight-cut cam gears.

Most VW boy-racer types love the sound. It gets kind of tiresome, so I put helical cut gears in my engine last go-around. I will put them back in next time. 

But the straight-cut cam gears might make a different (quieter) noise than a tranny gear and act differently when the load is removed.  Kind of hard to explain/diagnose on here, for sure.

I’m with Danny on this one, and agree that it is probably the front bearings inside of the nosecone.  I’ve replaced them years ago (a simple bearing puller pops them right out) but now I would also want to check everything else inside to make sure all is right before putting the tranny back.  The bearings available for this application range from junk to fabulous, depending on source and $$$.  Who knows what was installed last?  

You go to all that effort to get it out, you might as well make sure it’s all right before putting it back.

MPH versus engine RPM:   Just do the same test, but keep it in third, run it up over 60mph, depress the clutch and let off the gas to see how it effects the noise as you drift down past 60 again.  It should be the same as doing the test in 4’th, but might be different.  The difference might tell you which bearing is bad.

That could very well be, Gordon, but until we know whether the noise is speed related or RPM related, we are ALL just guessing. 

Ewatub posted:

I don't know how to distinguish between speed and engine rpm related.

ALB, Gordon, EDSNOVA, Danny & Stan:

First of all thanks for you help.

If I understood correctly, super-diffs are generally NOT noisier.  I know "noisy" is relative, but my car does not sound "normal".  Also, it is likely the mainshaft bearing is the source of the noise on deceleration.

I am in Hawaii and don't have much confidence in local transaxle builders.  I would prefer to deal with a Rancho or similar.  I'm thinking I may be better off just replacing the transaxle all together.  Locally, parts & labor gets close to cost of a replacement and shipping.

As was mentioned, quality of parts varies.  Can you suggest a transaxle builder who is competent and uses quality parts?  As you probably noticed, transaxles are out of my wheelhouse, my knowledge is limited to removing and replacing.

I'm a cruiser, I don't rabbit on greenlights.  It sounds like a transaxle like Gordon's would probably work for me.

Let me know your thoughts.  Ewatub

When I replaced my forward transaxle mount with a Rhino mount I noticed that I could hear the tranny noice a bit more, including a but of a bearing sound when coasting.  I doubt that anything changed in the transaxle, just that he firmer mount transmitted more vibration to the chassis.  Could it be something similar?

To some degree, sure, but there’s more than just that going on here.  It’s not supposed to be dramatically changing the noise level between acceleration/cruising and deceleration.   Always tough to diagnose a “noise” with back-and-forth posts, of course, and Stan could well be right, in the end.

The rebuilt Muncie M-20 I put in my old Nova made all kinds of humming and grumbling noises when we fired her up that first time. My then-boss Sam stole the first drive with me in the passenger seat, and I was immediately alarmed by all these ominous new sounds.

"Grumpy transmission," he said, pressing down on the gas pedal. And that was that. No remedies were forthcoming.

That was in about 1986. The trans was making the exact same noises in 2003, when I sold the car, having covered several 10s of thousands of miles in the meantime (it had been my daily driver in college, and I drove it out to Columbus Ohio when I moved there, etc.)

The rebuilt IRS box in Bridget is also not perfectly silent. I took a look at the oil in it when I changed it last year. Nothing in there.

Which is a long way of saying that, pace Mr. Pipperato, more likely than not, you don't have a problem.

I'm sorry Ed, but it ain't a Muncie. If the noise is on deceleration only, and goes away when pushing the clutch in in neutral, it's the mainshaft bearing. Period.

If the noise continually gets louder with time, there can be no mistaking it. Check the trans drainplug for steel "hair". If it's a little bit, fine, if it's full of hair, then it's one bearing or more. Also, the fulcrum plates and paddles on the axles wear and produce "hair".

Either way, after 300 miles, any transmission that is new or rebuilt should have the oil changed as per Bentley manual. It's cheap to change 5.3 pints of gear oil to get an indication of what's going on.

If the trans was rebuilt by a middle of the road rebuilder, chances are they put used or Chinese bearings in it. Cheap Chinese bearings: number one culprit.

ALB, Gordon, EDSNOVA, Danny, Stan & Lane:

Okay let's see if I did my homework correctly: (1)  Did the 60mph in 3rd, let the clutch out and got the same noise as in 4th.  (2) Did the 70mph, put in neutral, let the clutch out, no noise.

Let me know your thoughts.  Thanks Ewatub

Sickly mainshaft and countershaft bearings.

Gordon,  I'm leaning to ordering a transaxle like yours from Rancho.  Let me know if your have a contact there.  If yes, a name would be appreciated.  

Thanks for all your help, Ewatub 

Ewatub, do power on and then power off, in gear, clutch engaged(your foot not on it).

If the noise is there all the time, it's a pinion bearing or diff bearing, or one of the smaller bearings under the gears. If the noise is there ONLY on deceleration and in neutral, foot off clutch(you can clearly hear the difference parked when you press your foot on the clutch), then it's the mainshaft bearing.

Rancho contacts:

Sam Shackleford  1-800-304-8726    email:  samshack3804@aol.com

Also, Dave, there, is really good, too.  Very competent and friendly shop. 

Depending on what your engine is, they can quote you pretty much anything you want.  Stock is fine up to a 1915.  Larger displacement than that should have a Pro-Street.  You also want a 3:88 ring and pinion.  Lots of discussions on here about "optimal Gearing" so just do a search on transaxle gearing.  My tranny is a Pro-Street with stock VW gear ratios with a 3:88.  Nice and quiet and I like it a lot.

If you're planning on shipping out your old core, plan on $80 to get it there.  I might suggest you wait til you get the new transaxle and then use their box to ship the old one back for the core charge.

Ewa, are you a Hawaii VW Club member? Lots of very knowledgeable VW guys on Oahu and I would not hesitate to reach out on they're Facebook page.

Gordon Nichols posted:

Rancho contacts:

Sam Shackleford  1-800-304-8726    email:  samshack3804@aol.com

Also, Dave, there, is really good, too.  Very competent and friendly shop. 

Depending on what your engine is, they can quote you pretty much anything you want.  Stock is fine up to a 1915.  Larger displacement than that should have a Pro-Street.  You also want a 3:88 ring and pinion.  Lots of discussions on here about "optimal Gearing" so just do a search on transaxle gearing.  My tranny is a Pro-Street with stock VW gear ratios with a 3:88.  Nice and quiet and I like it a lot.

If you're planning on shipping out your old core, plan on $80 to get it there.  I might suggest you wait til you get the new transaxle and then use their box to ship the old one back for the core charge.

I'm told that Mike Herbert is also very good to talk to at Rancho. As for the level of build, I have a different take on it than Gordon. Even with a stock or relatively mild engine, you'll eventually break a stock transaxle with any kind of "performance" driving. If you can guarantee yourself that you'll NEVER drop the clutch and ALWAYS roll on the power then maybe you'll be ok, but otherwise go for the Pro Street upgrade and you won't have to worry about it.

The 3.88 r&p is great for the highway, but if you value the car's off the line quickness at all then the 4.125 maybe something to consider.

So many details... Al

PS- Just so you know- these transaxles, engineered for 60 hp, will always make some noise on deceleration in the higher gears. They're simply not made to handle the thrust loads (on deceleration) put upon them by higher powered engines.

ALB, Gordon, EDSNOVA, Danny, & Bill:  I'll contact Rancho and contact Sam, Dave or Mike.  

My car has a 2180 so the Rancho Pro-Street, super-diff & 3.88 is what I will discuss with Rancho.'

Bill: I did reach out to the Hawaii VW Club and used the local transaxle builder they recommended and I don't think it was good work for the $1,000 plus I paid.  What I know about transaxles and $5 bucks will buy you a bad cup of coffee, but I do know when one is making way too much noise.

I can remove and replace transaxles which is the extent of my knowledge.  The local Hawaii builder I used was a shade tree part timer.   I messed up thinking I would save on the shipping, false economy.  It's time to use a professional builder.

I have some things coming up so I will get with Ranch a little later this month.

Thanks guys, I'll let you all know how it goes.  Ewatub

Good luck, man, and sorry for your trouble. 

Tell you what: if I paid a guy a grand for a trans build and got a bad main shaft bearing I'd track the dude down and let him know. 

I've had two worked on by the same guy now and I sorely hope this second one is as good as the first. . . .

EDSNOVA, unfortunately, this transaxle has less than 1,500 mi so I'm pretty sure the faulty bearing was faulty during the rebuild and should have been replaced.  I may have it wrong, but I always thought competent transaxle builders would have to be focused and meticulous about component wear and fit tolerances.

I know a little about being focused and component tolerances.  I reload rifle rounds, the smallest deviation can turn a rifle into a grenade.

Thanks again for taking the time to help me out. 

Yeah, Ed is on target. If I paid a guy $1000 and he didn't put in brand new best you can get (German or Brazilian) bearings I'd be pissed off to say the least.

I rebuilt my own, and including buying a press and making some tools, I'm out of pocket $600. $400 or so went to Weddle for synchros, bearings, fulcrum plates, side gears, and gaskets and seals. Less than $150 on the HF shop press, and miscellaneous: gear oil, a couple 8mm studs , 8mm nylock nuts, and sockets(32mm for main shaft nut) made up the rest.

I started with a Trans West(now defunct) with welded 3-4, super diff, 3.44:1 Ring/Pinion, and stock 1-4 gears. That was built in 2002, and after I beat it for 35K, it was time. 35K is a lot different than 1.5K. 

As a small aside, I had an Austin Healey overdrive gearbox rebuilt by Quantum Mechanics in southern Connecticut.  When I got it back ($800 lighter) it was, according to another Healey friend who really knew his stuff, “Way tighter and responsive than a new one”.  That is kind-of what you want and expect when you dump a lot of cash on someone to do their job.

Gordon, I had a '56 100-4, that was more rust than car.  Unfortunately, I was young & couldn't see past the swoopy body lines and folding windshield.  Thing ran great.

Like most people, I want good value for my after tax dollars.

You definitely need to find another shop if you don't have the inclination to do it yourself. I added up the shipping each way and the rebuild cost.The numbers didn't add up for me. And I know I did a good job, not necessarily better than a trans shop.

They all told me I couldn't do it myself on here.

@Ewatub

I'm sorry to hear that...Please keep us posted. 

DANNYP O & Bill

Dannyp O:  If you have the skill, knowledge & time, your way is bulletproof and likely the most economical.  Can't beat complete control over your trans repair shop.  Sucks to be us regular folks who have to go retail.

Bill: Using the local builder is on me.  My gut told me to go with a professional shop.  This was just me trying to be penny wise and ending up being dollar foolish.  I'm not mellow about this, I've already done the can kicking and harsh language.

As you all know, if you can't deal with the disappointment from time to time, better go do something else.  I know, time to shut up and move on.

Thanks again for helping me out.  Ewatub 

There is no "O" after my screen name, that's a little gizmo that is dark if you're online, an empty circle if you're not LOL.

Really??   I always thought that indicated the contents of my wallet...   

DANNYP:  Time for me to shup up and move on.  After just a couple of posts, you already know I ain't that handy with forums.

Gordon:  Good point.  Wallets can be a flotation device or an anchor.

Do keep us posted...Aloha!

Howdy all:  Ordered up the Gordon Nichols spec transaxle from Rancho via Sam.  gods willing and the creek don't rise, should be here mid November.  Now comes the hard part, waiting.  I don't do waiting well.

IKSUAMO 

Followup to superdiff question:  Ordered transaxle from Sam @ Rancho, installed it about 2 weeks ago. Take away is - go with pros.  After about 150mi, car is a lot more fun to drive, and making good noises.

I sorta went nuts, aside from the set up Gordon has, added Rhino case, little taller gears & second sideplate. (I'm OCD about symmetry).  It's too bad it's under the car.

Thanks again guys, be safe and well in the coming year.  

Ewatub posted:

...added Rhino case, little taller gears & second sideplate....

What gears did you change? And did you ever ask the guy who built the trans for you about it?

ALB:  I don't know if Sam over at Rancho is a builder,  but I discussed with him how I wanted the car to drive.  Due to my inexperience as relates to gear ratios,  Sam took the lead and the car drives the way I wanted.  Further, transaxle noises on deceleration north of 60mph, quieter than my other car.

When I received the Rancho transaxle, an attached tag showed 3.80, 2.06, 1.26 and .89.

I did have a general discussion with Sam about Rancho's build process, but not technical.  

ALB, have yourself a great 2019.  I'm moving from vw transaxle swapper to house painter.

Those are good stock-sized gears to have.