MGW GT350 shifter - second run

[J_Maher_AMG]

[MENTION=19066]Epiphany[/MENTION] loved the write-up man, very intriguing read for sure. As you mentioned, it is too bad that Ford doesn't divulge more in the way of details concerning the efforts put in to mitigating some of the vibration issues.

Very interesting tidbits there at the end as well concerning the carbon driveshaft testing. Do you think then that even an aftermarket unit like the DSS shaft would be a detrimental addition to the drivetrain or have any ill effects, even if they have utilized a different connection than what is used by the factory?

Sponsored

 

[Epiphany]

I am one of the few who called George about nvh issues.

Essentially at about 4-6k ish there would be heavy vibration with the shifter which would go away as I revved higher.

This wasn't present with the oem shifter. I did remove the shifter and made sure that there was no binding.

I'm very excited about this.

Looks to me that the only difference after upgrading the first gen shifter is that the shifter box won't have that lighting cut in it for weight savings?

Otherwise I do love this shifter!

Very odd that it wasn't present with the OEM, was pronounced with the MGW, and then (I assume) went away when you reinstalled the OEM shifter. You have the OEM shifter in place now, correct?

If you went from OEM to the MGW and have this vibration (and didn't revert back) I'd be looking elsewhere to begin. The service manual shows the closest issue related to your description as a "driveline vibration." You may disagree with the "cruising" portion but the idea is rpm within a range and at speed. Was your driveshaft removed at the front? If so was it indexed back the way it originally was?

Try to eliminate the following...

Verfiy the torque at the front U-joint...

Verify that your driveshaft center joint bolts are in place and torqued to spec...

Verify that your rear mount is installed in the correct orientation and the nuts are appropriately tightened...

And lastly, that your transmission isn't preloaded such that the mount underneath the transmission isn't in a neutral position. You can do this by placing a jack under the transmission and putting a slight amount of upward pressure on the case, loosening the four crossmember bolts as well as the two mount nuts such that the trans could be pushed laterally if need be. You don't need to allow it to lower very far. If it is preloaded, it will relax itself when you loosen the bolts. Go back and tighten the crossmember bolts and then the mount nuts. Be sure that you aren't applying a lateral force when raising or lowering. The following photo is used for reference but doesn't follow the procedure I just outlined. In other words, you wouldn't be placing the jack under the crossmember as shown but rather the transmission.

ON EDIT...one more thing. In addition to the crossmember bolts, etc, verify that the three damper bolts are torqued to 76 lb-ft. While Ford preapplies quite a bit of thread locker on the bolt threads used here, this could be a problem area if the weights were never torqued properly in the first place. Or if an installer inadvertently removed and reinstalled them.

And the answer is more or less yes regarding the weight removal to the box.

Epiphany, I have the cabin vibration that is also felt through the seats. Is it possible, and likely to help, to adjust the position of the tail of the transmission via the slots in the cross member to reduce this vibration? When I have my upgraded kit installed I can have my shop give this a try.

Hey Bob. Verse yourself on the above and if you can have them check and verify what I showed above. Have them show you the finished install while the car is up on a lift if they will allow you. Trust but verify.

@Epiphany loved the write-up man, very intriguing read for sure. As you mentioned, it is too bad that Ford doesn't divulge more in the way of details concerning the efforts put in to mitigating some of the vibration issues.

Very interesting tidbits there at the end as well concerning the carbon driveshaft testing. Do you think then that even an aftermarket unit like the DSS shaft would be a detrimental addition to the drivetrain or have any ill effects, even if they have utilized a different connection than what is used by the factory?

I hate to speculate on DSS offering as I don't know the details on the shaft they use in this case. If they can do what the factory wouldn't - more power to them. It'd be great if they provided some of their own test data with respect to instrumented testing and vibration both before and after one of their CF shafts were installed. I'm sure the community would love to see it if it were positive and it would no doubt help with sales.

 

[xXANCHORMONXx]

I actually put the MGW backin. I removed it to inspect it and followed George's recommendation to loosen the bolts and kind of bounce it all around.

After reinstalling the oem shifter that nvh was gone but I wanted the solid shifter more than the nvh bothered me.

Thanks for the recommendations, when I pull it again for the revised retrofit kit I'll post up any changes

 

[xXANCHORMONXx]

Also I did have his race spec on my EB PP with a CF DSS driveshaft and white line trans insert. I know it's a totally different motor but it was fantastic. Nvh increase was minimal at best

 

[Epiphany]

Can you be more specific about the vibration you are seeing? You mentioned the rpm range but is that in every gear when at that rpm? Is it the same under acceleration in that range, cruise, and deceleration? If you place the transmission in neutral and rev to that range is it still present?

 

[SlowArrow]

Great write-up Epiphany! Vibration management/control is very challenging. I work for a company that builds some extremely vibration sensitive equipment. Tolerance control, mass damping, creating impedance mismatches......it is a pretty complex engineering game. I could see that any misalignment in the drivetrain that totally compresses the rubber isolators would result in a "short" and rendering the isolator ineffective - increasing vibration. Seems like if someone had a serious vibration problem, they should verify that there isn't an alignment problem in the drivetrain.

I also wonder what the Ford engineers found out about a CF driveshaft, what caused them to decide to install a two piece steel driveshaft. A two piece has got to be more expensive than a one piece - just wondering about the claim that the choice was all about cost. If they isolate drivetrain vibration from the body using that complex, heavy cross member, I'm guessing there remains some significant motions at the tail shaft of the tranny. I wonder if that is why they chose to install short really stiff drive shaft sections. I'd love to see the engineering analysis that went with that decision.

 

[xXANCHORMONXx]

Can you be more specific about the vibration you are seeing? You mentioned the rpm range but is that in every gear when at that rpm? Is it the same under acceleration in that range, cruise, and deceleration? If you place the transmission in neutral and rev to that range is it still present?

It's more pronounced after 3rd gear. Decel and accel yes. Cruise as well.

When I rev in neutral it does too.

But again with the oem setup it doesn't do that.

 

[CSL]

Sorry if this has been posted, but what is a good price to have this installed? Should I find a specialty shop to do it?

Thanks!

*Im in the Seattle area or I'd try to sweet talk George into helping.

Go to Brad's Custom Auto in Lake City area. Very honest shop with top notch techs.

 

[CSL]

Note that Ford revised their own TR3160 design in an attempt to mitigate NVH complaints. I hate to use the polishing a turd analogy but in essence the factory shifter stills suffers NVH issues in certain cars.

This is a great conversation and I enjoy the exchange of ideas along with hearing different points of view. Excessive NVH can ruin an otherwise great driving experience. How a given car can deviate in terms of vibration from another that went through the same manufacturing/assembly process can be a bit of a mystery. George has suggested exploring driveline alignment in the past and I believe his thought process definitely has merit.

It would be great if we could assume that all of the driveline components are within factory specification (and that the design that drove those specs is proper) on each and every car. I'm not convinced that they always are or that extreme care is given in terms of dirveline alignment on the assembly line.

I do have a bit of experience with respect to certain SVT transmission variants in a number of ways. Most recently the GT350's TR3160 and the TR6060 from the GT500. In the case of the TR3160, starting with the transmission crossmember in the GT350. I dimensioned one so that I could better study it in CAD (and along with it, the mount).

It is a very lightweight piece. For an aluminum casting is is very rigid. Note that the holes at the outer ends of the crossmember are slotted.

Those slots allow for a fair amount of lateral "adjustment" such that the tail of the transmission can be moved one way or the other. The engine at the front mounts fits over studs and the mounts themselves sit in/on the factory K-member (which has room to move when fastening as well). There are a couple of potential issues here. First, the engine/transmission can be positioned such that there is undue lateral pressure on the rear shifter mount that attaches to the floorpan. The issue is that the two guidepins can preload the rubber mount. This compresses one side of the mount and unloads the other. This can or could cause additional vibration to pass through and into the cabin.

The other issue is that the transmission needs to be in a neutral position (not gear but rather the case itself) when tightened to the floorpan. If there is excess lateral pressure you are once again preloading the mount. This can happen when you use a floorjack (which usually swings in a radius) to raise the transmission/crossmember up such that you can install the bolts and tighten them up. Much of the driveline weight is carried by a very small area. The molded rubber just above the studs in the following photo carries everything that isn't also shared with the front engine mount.

You then have weight Ford found necessary to help quell the raging harmonics generated by the Voodoo engine.

You'll never see (I know I never have) Ford comment publicly on the specifics regarding how they addressed vibration on the GT350. It has been mention in passing (and quite passively at that) but never directly and with detail. That said, the GT350 has almost 13lbs of weight added to the rear of the transmission that isn't used on any other Mustang engine/transmission combination. This is significant in and of itself in the context of all the weight reduction that Ford did with this car (CF, aluminum, etc) and shows how critical and necessary it is for this application.

If your car was outside the range in terms of driveline vibration/frequency then the above added-on weights won't be able to minimize or eliminate in-cabin NVH. The weights are designed to work in a certain range and in most cases do a pretty good job.


Something else. I think most everyone had hoped to see a CF shaft in this car, myself included. It seemed a natural. Especially given what we were told about how necessary it was for the '13/'14 GT500 in order for it to be able to break the 200mph threshold. Ultimately, we were told that Ford couldn't get the stiffness necessary from a CF shaft in the case of the GT350. I've struggled with that but defer to the engineers that made those comments publicly. Ford did test CF shafts in the GT350, evidenced by pre-production prototype undercar photos. One thing is for certain, there were issues at the tail end of the transmission beyond just the weights needing to be added.

Length.

Steve Turner paid a visit to Tremec's headquarters in Michigan on behalf of SVT performance (dotcom). The visit had to do with a writeup on the upcoming TR3160 transmission. On the table before him lay a couple of well tested test units that were disassembled. I studied the photos in Steve's writeup very carefully and something stuck out immediately. I noticed one photo of Nate Tovey of Tremec holding a fixed flange next to a cup-style flange that was installed on one of the transmissions. Note the depth of the nut in each case...

In talking with Steve I learned that Ford was seeing a "wag the dog" type of effect and that the solution was shorten the flange as much as possible. That meant no cup. Without a cup, no CV joint, hence the U-joint used on the front of the GT350.

Enter the TR6060. I worked on a solution that allowed physically bolting on a '13/'14 CF shaft to the prior year GT500's ('07-'12). This is why I noticed what was going on with the TR3160, immediately. I believe Ford engineers had originally used the cup flange from the '13/'14 on the TR3160 during development. In the following photo the CF shaft-ready flange is on the right and the earlier, U-joint only flange, on the left.

Some CAD design was done followed by machine work.

I sold a good number to GT500 owners. What I learned was how sensitive a given driveline can be. The CF shaft proved to really quiet things up. But most importantly and relevant here was how the TR6060/5.4 or 5.8 was nowhere as near as sensitive in terms of transmission length as the the TR3160. While cost may have indeed been a factor, the fact that Ford had to forego a CF shaft due to the vibrational characteristics in the GT350 is remarkable.

That said, don't ever remove the weights. They absolutely serve a purpose. And be very wary of any bracket, shifter, etc, that attaches to the area of the weights (think shifter, shifter support bracket, etc). There is a reason why MGW uses the stock rear shifter mount or bushing - because it works. The durometer and shape/design work very well and an aftermarket mount would just be an unnecessary expense that most likely wouldn't outperform what the factory came up with.

Sorry if that was a bit long winded but this has been my experience.




Given you've witnessed what sounds like excessive NVH characteristics with two GT350's now I am really looking forward to your experience with the MGW unit.

OK.....now everyone knows why I call him Professor, nuf said!

 

[Money2536]

What a great read! Thanks for all the content Epiphany! I'll make the call to order MGW this week.

 

[Draughn]

Go to Brad's Custom Auto in Lake City area. Very honest shop with top notch techs.

I'll do that. Thanks buddy

 

[cking]

So anybody installed version 2? How is it?

 

[altjx]

I haven't even gotten mine yet. Anyone have theirs? Wonder if I need to call back or something. Think I talked to someone mid last week and was told they'd ship it right after they got one more part or something along those lines.

Good to see [MENTION=26878]Money2536[/MENTION] Matt up in hurr!! About to go catch up on the vids right now

 

[Spacebird]

I haven't even gotten mine yet. Anyone have theirs? Wonder if I need to call back or something. Think I talked to someone mid last week and was told they'd ship it right after they got one more part or something along those lines.

Same boat.

Any idea if the second run makes anything worse? I like everything about the shifter but the NVH, but as I drive my car once a week at most, I kinda don't mind the visceral experience. If I have to give up something I like I'm not sure I want to switch it out.

 

[altjx]

Same boat.

Any idea if the second run makes anything worse? I like everything about the shifter but the NVH, but as I drive my car once a week at most, I kinda don't mind the visceral experience. If I have to give up something I like I'm not sure I want to switch it out.

Yeah I'm personally not sure but that's a really good question. I drive my car probably more than 99% of the GT350 owners out there and would also rather not sacrifice anything

Sponsored