Paul 75 L82

I'm getting all of my parts together for a clutch/transmission change out and I'm planning on changing the torque tube rubber couplings. Can you reuse the bolts from the coupling or do I need to buy new? Other than GM where's the best place to buy the rubber couplings?

cgm12mgc

you can buy the couplings at the BMW dealership or ebay for pretty cheap, exact same couplings.... the bolts can be reused, aslong as there is no damage to them, mine snapped a few days ago when my coupling destroyed itself so ive got to replace it all.... good move replacing those couplings!

Paul 75 L82

The only part number I have for the couplings is 12456212. I think that's the 12mm part number. Do you have another part number?

bumble-z

Paul, you could give ECS, MTI, etc a call. They would give you the answers that you need. They could probably ship out the parts to you too. You don't want to mess up this part of the job. Good luck.

Eric D

Here is a list of the part numbers. I would also suggest caution on where you purchase the couplings. They are not all the same quality.


BOLTS
Bolts for mounting the flex couplings use the following bolts.

Part # 12456213 = Torx M10 x 47 mm 12 each
Part # 88894027 = Torx M12 x 52 mm 12 each

bumble-z

Great info, as usual Eric!

Paul 75 L82

Eric, I Googled 88894026 and I found a nice chart. Thanks for the number.

http://www.gmpartsgiant.com/componen...tmm61yy67.html

~Josh

I've heard that the BMW peices aren't the same.... and deteriorate. I'm not calling you a liar, it's just that there seems to be conflicting reports both for and against in different threads.

lionelhutz

Some real junky couplers out there. I'd be tempted to do a solid coupler in the rear and shim the bolts so it runs true. Then, do the new Prothane poly coupler in the front. Best part is that you never worry about it again.

In fact, I expect I'll be pulling my car apart again soon and doing just that.

Peter

Eric D

Peter,

Your plan is OK as long as you understand that you are also the R&D department. I however would not suggest this to anyone as the parts have not been proven to be any better than the stock couplings that every C5 & C6 including the ZR1 use. GM guarantees them for 100K miles in the current Corvettes. Ask any of the aftermarket suppliers if they will give you that kind of warranty on their product.

If I have to replace mine I would go with nothing but the OEM coupler. There are good reasons why GM still uses them. Just my humble opinion.

Paul 75 L82

I'm going to buy the stock OEM couplings, it's not worth the hassle to save a few bucks. But my mechanic said that I should buy new bolts.

Eric D

It sounds like you and your mechanic have this well under control. I agree with both of you!

lionelhutz

I'm quite fine with that.

It seems you know why the GM engineers picked the couplers so why don't you share?

If you have real proof that the Prothane coupler or a solid rear coupler are downgrades then post it up.

Despite the GM warranty, there are cars here that have had shredded couplers in a lot less than 100k miles.

On a similar subject, why would GM put in a skinny little prop shaft with a composite disk on it to keep it from becoming a skipping rope at high speeds when they could have put in a larger diameter shaft?

A manufacturer would never compromise....

Peter

Eric D

As far as sharing, I think if you look through the thousands of posting I’ve made on this forum that I do a lot of that. However, there are some things that I cannot share due to obligation that I respect. In all my postings I do the best I can to caution and flag things that could cause someone real issues and I will on occasions PM a person and talk one on one.

I’m not quite sure why you feel I should prove out every new product that someone else comes up with. Should not that be the responsibility of the company introducing their new and improved widget? It is common that some suppliers do little to no R&D and use their customer base to test things. It is only my opinion, but I believe that the burden of proof of goodness or badness should be on the company supplying the product.

As far as your reference of shredding couplers with less than 100K miles, without investigating the vehicle’s history in detail there is no way to know what the cause of the failure is. What I can tell you, changes made that someone thinks are minor can have a big impact on the durability of other components.

Compromise, well, isn’t that why we have engineering? Engineering is taking as many factors as possible and developing a component with the best balance of all those factors.

This forum is filled with some very interesting people with backgrounds in a variety of disciplines. It’s a fun place to learn and read about new and in my opinion interesting things. This is the driving force that keeps me coming back. How about you?

SteveDoten

90% of c5 stay below 400hp

these cars are fine oem

Paul 75 L82

I bought OEM couplings and bolts from Gene Culley today.

lionelhutz

Doesn't give you the right to dismiss them either as not likely being as good as the stock couplers.

Using the ZR1 100k mile warranty as proof is questionable. In my opinion, if a ZR1 gets flogged much while being driven the couplers will not last 100k miles. Also, none of them have enough real world miles to make any claims that the couplers do work for 100k miles in that car.

Peter

Eric D

Hmmm, I guess I didn't see the bill of rights Peter. Does this mean I'm not intitled to my opinion? I get the impression no matter what is presented to you as reasonable, your opinion is fixed.

Really, so, are you familiar with the durability testing at GM? Care to explain what factors in this testing are flawed?

I really need you to explain the "rights" you talked about above, it sounds like I'm not intitled to my opinions, yet you can have yours?

Really, are you monitoring all the miles on every ZR1 out there? Where are you getting this information?

LoneStarFRC

I'll be the guinea pig. I'm getting 2 new Prothane six-shooters installed next week.

I agree with the others here on re-using the coupler bolts. Only if undamaged of course. If any are in doubt however, replace.

Eric D

It is nice that you agree to be their guinea pig! Are they at least giving you a break on the cost seeing you willl be doing their R&D? Note that in their warranty they will only cover for the price of their part if it fails and if it's not abuse.

On a more Sserious note, if this really is your plan, how about getting photos and starting your own thread with the topic of these couplers. How much hp are you at, what diff gearing and other details on your car. I'm interested and I'm sure others would be as well. I hope they work out for you.