Lightweight Driveshaft Recommendations?

FenixBirdWing

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Oct 28, 2009
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Hey guys - I've been researching different options for the first mod to my new '09 GT. :D Contrary to what most people seem to do, I've settled on not getting a CAI/tune until later down the road (probably 2nd or 3rd mod). I've decided to go for a set of rear gears and driveshaft swap first. Figure the gear swap will require re-calibration of speedometer - this way I don't have to get a custom tune twice (once before gears and once after).

I think I'm set on the FRPP 3.73 gears (4.10s seemed like they might be a bit steep for a daily driver that sees a lot of highway mileage) and have seen a lot of recommendations to just have a Ford dealership put them in right the first time and hopefully reduce the chances of having to bring it back in for gear whine.

Figured since I'd be having the gears changed out, this would be a good opportunity to also swap in an aluminum (or other reliable light-weight) driveshaft. So far I've only checked out the Dynotech driveshaft - I was wondering if anyone else has had good/bad experiences with different driveshafts and/or any other thoughts/recommendations for a complete newbie like me?? :scratch:

Also, do you guys think swapping the stock S197 GT driveshaft with an aluminum driveshaft is something I could do in a driveway with 4 jack stands? I'm looking to do as much work on my own as I can with the tools I've got access to if only for the experience. I've heard changing the driveshaft isn't all that bad. On the other hand, I've read about nightmare experiences trying to change out the rear gears.
 
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I only have personal knowledge of some budies running the Spydershaft and none of them have ever had any problems. The driveshaft swap isn't too difficult. I haven't done one on mine yet. About the gear swap...unless you have the proper tools and knowledge using them, I'd pay the $500 (parts & labor) and have it done professinally. FRPP has been proven to be the gear of choice for minimal issues. What gears do you have now? If you have the 3.55s, I'd advise against the 3.73s unless you're going with a power adder. I've had the 4.10s in my car for about 74K miles now and I do all kinds of highway driving and I've never had an issue or been annoyed with the RPM range. There are even some that have 4.56s in their daily driver! When I don't have to drive my car about 25K-30K miles a year, I'm going to step up to the 4.56s!
 
I have had a Spydershaft for over two years with no issues and no vibration at 120+ mph. There are several brands out there to choose from but I would personally avoid any with "adapters" instead of an exact fit.
 
Ron Leonard who owned and built the Spydershaft just sold it to JPC, not that it's a bad thing.

Irregardless, the Axle Exchange driveshaft who builds the driveshafts for Steeda seems to be the least problematic and I've never heard of vibration issues with it. Otherwise my second choice would be Dynotech. Both great products. I wouldn't waste my time with any other driveshafts.
 
The Axle Exchange is the only one I haven't read complaints on. It seems to be hit and miss with others if they vibrate or not. Alot of people have no problems but there are enough complaints to steer me away from other brands.
 
I only have personal knowledge of some budies running the Spydershaft and none of them have ever had any problems. The driveshaft swap isn't too difficult. I haven't done one on mine yet. About the gear swap...unless you have the proper tools and knowledge using them, I'd pay the $500 (parts & labor) and have it done professinally. FRPP has been proven to be the gear of choice for minimal issues. What gears do you have now? If you have the 3.55s, I'd advise against the 3.73s unless you're going with a power adder. I've had the 4.10s in my car for about 74K miles now and I do all kinds of highway driving and I've never had an issue or been annoyed with the RPM range. There are even some that have 4.56s in their daily driver! When I don't have to drive my car about 25K-30K miles a year, I'm going to step up to the 4.56s!

I'm pretty sure the stock '09 GT's come with 3.31s. That + slow throttle response (not tuned yet) = me getting tired of getting beat at the light (during daily driving) . :mad: Who knows tho - it could just be my driving :shrug:

I was thinking 3:73s because I was afraid the jump to 4:10s would put me at a constantly high RPM range for highway traffic but now that I'm doing the math it might not be that bad - maybe like 3800 RPM @ 90 mph. You make me reconsider the 4.10s :scratch:
 
I'm pretty sure the stock '09 GT's come with 3.31s. That + slow throttle response (not tuned yet) = me getting tired of getting beat at the light (during daily driving) . :mad: Who knows tho - it could just be my driving :shrug:

2005-2006 came with 3.55s standard in the manual cars.

2007+ came with 3.31s standard with the option for 3.55s in the manual cars.

I'm not quite sure about the automatics. I believe they have all came with 3.31s standard but 3.55s were an option.

Hope this helps. :nice:
 
I have been researching this also. I am leaning towards the Axle Exchange or DynoTech pieces. I think like the fact that the DynoTech is 3 1/2" (the Axle Exchange and some others are 4"), I have read this gives the extra clearance that is sometimes needed, and something about the rotational mass as far as vibration??
 
I have been researching this also. I am leaning towards the Axle Exchange or DynoTech pieces. I think like the fact that the DynoTech is 3 1/2" (the Axle Exchange and some others are 4"), I have read this gives the extra clearance that is sometimes needed, and something about the rotational mass as far as vibration??

The Axle Exchange is actually a tapered design so there is no issue with clearances. :nice:
 
Last weekend I put in a Shaftmasters with the pinion adapter plate thingy. I also put in an adjustable UCA and mount to make sure I got the pinion angle right. It was all pretty easy, just time consuming if you don't have power tools. Overall I am really happy with it. It definitely makes a difference. I have some up close comparison pictures of the shaft, UCA, and mount if anyone is interested.
 
Here are some pictures of my Shaftmasters driveshaft, BMR UCA mount and BMR UCA.

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Who doesn't like pictures right?
 
I went from 3.31s to 3.73s. The 3.73s are a little over board for what I use the car for but just barely. They represent a 12% RPM increase over stock. 4.10s are a 22% increase over stock and would be excessive in my opinion.

I went with the Coast ultralite 4" shaft which has a critical speed of nearly 8,000 RPM which with 27" wheel diameter and 3.73s would be good for over 190 MPH. Ought to be enough.

You will take a 10% cut in Highway MPG if that matters to you. Around town is up to you. The higher RPMs will allow you to get into the higher horsepower range sooner. But horsepower comes from gasoline. So with the lower gears you have the ability to burn more. If I granny drive in town I got a little increase in MPG.

The part you can feel. All the gears pull harder. 5th will now pull 6% grades at 55Mph where I would have down shifted into 4th below 60. It also picks up faster when lane jockeying. I can stay in 5th now where as before I would be taking 4th or even 3rd. Third is an awesome passing gear even up a grade. 2nd used to take me all the way up the on ramp and into lane position. Now I need to get into 3rd before lane position because 2nd is tapped out. Off the line hard be ready for the 1st 2nd shift to come up fast. I am seeing some black on the rear wheel well skirts although I am not hearing any squealing. When going slow, like in traffic jams or parking lots, 1st at idle seems to pull along better with less clutch feathering. I tend to agree with Mark at Coast drive line, The 3.73s are the best for the S197 GT for drive-ability and performance. 4.10 could be if the transmission were geared different. Especially a higher 1st.
Speaking of transmission gears, with a 3.73 rear, it would be interesting to change the 5th in the 3650 from its .68 to the optional .63. That would restore 5th back to its highway flier configuration and get back most of that MPG lost with the lower rear gears. I wonder how expensive that would be.

I vote for what I did. 3.73s for your daily driver.
 
thanks for the pics, zero. the new shaft looks so much sturdier than the old one.
cusp, did you see enough gain from the 3.73's to make the whole procedure worth it? i've got 3.31s now and would like to go with something bigger, but i don't want every gear to seem like a granny gear and be winding out on the highway. OTOH, i don't want to spend a lot of time installing 3.73s and then not be happy with them.
 
No sweat. It is a LOT sturdier but what you can't see is how much it DOESN'T weigh. The weight difference is staggering. As for your gear choice issue, I just bought my 08 GT a little over a month ago. The guy selling it was so not wanting to tell me it 4.10s since he thought he might scare me off. I must admit I was concerned when he told me. Every other Mustang I have ever had had 3.73s. I drove the car and was amazed with the 4.10s. I drive the highway to work everyday and never get tired of it or think the engine is winding too high. The 3650's 5th gear is a lot better than the T-5s. That's just my 2¢.