Difference between drive shaft flange to IRS vs SRA spacer

[04Mach1Blurr]

Hey guys was wondering if any of you have used the JEGs or STEEDA drive shaft spacer with your Cobras? I am looking to install a cobra aluminum drive shaft while using my TR3650. I've been doing some research and found that my mustang's OEM drive shaft is 2 inches longer than the cobra aluminum drive shaft. I've located STEEDAs drive shaft spacer Steeda Hardcore Driveshaft Spacer for 1979-2004 Ford Mustang 555-7707. But it says for SRA only.

I'm trying to figure out what the difference is and why I can't use it on my IRS equipped Mach. Is it a different bolt pattern? Figured some of you guys may have a better understanding as I am not having much luck in my Mach 1 sections.

thanks,

Forgot to mention, I only swapped the flange in the differential when i did my IRS swap. So what I'm thinking, is that it is possible to just swap both flanges off my stock drive shaft and put it on the aluminum drive shaft. Think this will work?

 

[TRBO VNM]

The differentials have different flanges from the IRS and solid axle, as you know. So basically, to use your same driveshaft you took the SRA flange and put it on the IRS pumpkin, so then you did nothing with your driveshaft. And so I bet your driveshaft was tight since it is longer. lol

putting a terminator DS in is fine, but you would need a different u-joint and put the flange from your DS onto the terminator DS. You just need the new u-joint. The terminator is a 1350 and I think the mach 1/gt is a 1330. So you can get a "hybrid" u-joint that is a 1330/1350.

That said, you could just change the pinion flange back to a terminator setup and maintain the larger terminator u-joint.

 

[fastback brian]

the t-56 drive shaft is too short to use with a 3650... you dont want a spacer, better to spend the money getting a custom shaft built.. what drive shaft are you using? a stock mach1 drive shaft is on the long side for a irs swap. if it is a stock shaft and is working fine then you should be looking for a frpp aluminum drive shaft not a terminator drive shaft..

 

[04Mach1Blurr]

The differentials have different flanges from the IRS and solid axle, as you know. So basically, to use your same driveshaft you took the SRA flange and put it on the IRS pumpkin, so then you did nothing with your driveshaft. And so I bet your driveshaft was tight since it is longer. lol

putting a terminator DS in is fine, but you would need a different u-joint and put the flange from your DS onto the terminator DS. You just need the new u-joint. The terminator is a 1350 and I think the mach 1/gt is a 1330. So you can get a "hybrid" u-joint that is a 1330/1350.

That said, you could just change the pinion flange back to a terminator setup and maintain the larger terminator u-joint.

Thanks man! Yea I have the TR3650 with the stock Mach/GT drive shaft going into an 03 IRS (that you built up for me!) Thats what I was trying to figure out if the cobra drive shaft would be too short if I swapped over both my yokes (cobra drive shaft did not come with yokes, got it pretty cheap) added the hybrid u joint and added the steeda spacer to make it actually work.
The cobra shaft is what roughly 2 inches shorter than my stock Mach drive shaft.

the t-56 drive shaft is too short to use with a 3650... you dont want a spacer, better to spend the money getting a custom shaft built.. what drive shaft are you using? a stock mach1 drive shaft is on the long side for a irs swap. if it is a stock shaft and is working fine then you should be looking for a frpp aluminum drive shaft not a terminator drive shaft..

Thanks for the opinion, thats why i'm trying to do some homework on this first and if I can't use it, then i'll sell it and get the frpp aluminum drive shaft. The spacer goes right in between the differential and flange with upgraded longer bolts. If its tight like it should be against the differential, there shouldn't be excessive abuse correct? The major concern is if the drive shaft is still not long enough and has wobble or vibration due to the front yoke not far enough in.


Thanks guys for the help, keep it coming!:beer:

 

[fastback brian]

the spacer is not enough, they are maybe 1/2 inch thick.. and the terminator shaft will need a hybrid joint to fit the 3650 yoke and the mustang gt flange, or you can go back to the terminator flange but then the spacer wont fit....:shrug:

 

[shurur]

T45/T3650 to SRA is 45.5" (1996-98 cobra, 1996-04 GT "J"..and 79-93+ foxbody "G"
T45/T3650 to IRS is 44.5" (1999-01 cobra)
T56 to IRS is 43.5" (2003-04 terminator)

Ford makes 43.5" AL DS and 45.5" AL DS.

What you essentially have is a 1999-2001 cobra now.

What I just did was to buy a P-71 police interceptor AL DS on Ebay (55.5") and get it cut to 44.5", Flange, yoke and joints swapped over/replaced, balanced...works great.

Some 1999-2001 cobra owners have bought the Ford "J" AL DS (45.5") and wedged it in...it "works" because the the IRS is fixed in position...but there is no 3/4"-1" slop..I can't imagine that is a good thing.

*****************
Also...I believe they make a 31 spline yoke that is 8.5" vice the standard 7.5" yoke...(Summit racing??..Lethal??..late model resto..) that could make up that 1" you need if you go with the 43.5" terminator AL DS...as stated above you will need a 1330/1350 Hybrid U-joint to go from that DS to that yoke...but you should change the u-joint out for new anyway...

The advantage to this approach would be that you could have the original teminator yoke reinstalled when you get that T56 down the road ;-)

Others who actually know about this possible approach please chime in...TRBO VNM??

 

[04Mach1Blurr]

the spacer is not enough, they are maybe 1/2 inch thick.. and the terminator shaft will need a hybrid joint to fit the 3650 yoke and the mustang gt flange, or you can go back to the terminator flange but then the spacer wont fit....:shrug:

I agree upon both yokes needing the new hybrid joint to be able to work on the cobra aluminum shaft, (forgot about the front haha, but thats what these forums are for, R&D) The other thing is I bought the cobra drive shaft with out the yoke and flange since the owner needed them. Thats why I was looking to use my parts and swap it in somewhat directly with the spacer. Thanks for your thoughts as well!

T45/T3650 to SRA is 45.5" (1996-98 cobra, 1996-04 GT "J"..and 79-93+ foxbody "G"
T45/T3650 to IRS is 44.5" (1999-01 cobra)
T56 to IRS is 43.5" (2003-04 terminator)

Ford makes 43.5" AL DS and 45.5" AL DS.

What you essentially have is a 1999-2001 cobra now.

What I just did was to buy a P-71 police interceptor AL DS on Ebay (55.5") and get it cut to 44.5", Flange, yoke and joints swapped over/replaced, balanced...works great.

Some 1999-2001 cobra owners have bought the Ford "J" AL DS (45.5") and wedged it in...it "works" because the the IRS is fixed in position...but there is no 3/4"-1" slop..I can't imagine that is a good thing.

*****************
Also...I believe they make a 31 spline yoke that is 8.5" vice the standard 7.5" yoke...(Summit racing??..Lethal??..late model resto..) that could make up that 1" you need if you go with the 43.5" terminator AL DS...as stated above you will need a 1330/1350 Hybrid U-joint to go from that DS to that yoke...but you should change the u-joint out for new anyway...

The advantage to this approach would be that you could have the original teminator yoke reinstalled when you get that T56 down the road ;-)

Others who actually know about this possible approach please chime in...TRBO VNM??

Absultely appreciate the numbers man! I get your concept and have seen alot of other people cutting longer driveshafts down. I'm looking to try this out on the cobra shaft if possible to be able to add another option for guys not using a 31 spline yoke from the transmission such as myself and other TR3650/T45 owner. I saw the 31 spline yoke on summit, but I can't use it with the stock transmission correct?

So what I'm looking at now is my oem yoke+ hybrid u joint+ cobra drive shaft+ hybrid u joint+ oem Mach/gt flange+ the 11/16ths drive shaft spacer into the IRS differential. Leaving roughly (.5) inches short of the 00/01 cobra 44.5'' setup for an aluminum drive shaft utilizing the IRS. :read:

Is that correct? Are you sure about the 1inch loss of the TR3650 from SRA to IRS?

 

[shurur]

Sure about the 44.5" T45/3650 to IRS length...yes this is the difference between the length between SRS/IRS with all else being equal.

I just measured mine a few days ago..and we both know what ford sells...I had been looking at AL DS for a while..and am read up.

Ford 31-spline yoke works for T56, T45 and T3650 transmissions; so, it's just a matter of Terminator 1350 or hybrid 1350/1330 for T45/3650 31 spline yoke to terminator DS.

Again the standard yoke length is 7.5"...and I believe there is a 8.5" yoke...probably 1330.

Don't know about the flange differences for SRA/IRS yet...but do know my IRS flange had to be swapped over to the P-71 DS..

 

[04Mach1Blurr]

Sure about the 44.5" T45/3650 to IRS length...yes this is the difference between the length between SRS/IRS with all else being equal.

I just measured mine a few days ago..and we both know what ford sells...I had been looking at AL DS for a while..and am read up.

Ford 31-spline yoke works for T56, T45 and T3650 transmissions; so, it's just a matter of Terminator 1350 or hybrid 1350/1330 for T45/3650 31 spline yoke to terminator DS.

Again the standard yoke length is 7.5"...and I believe there is a 8.5" yoke...probably 1330.

Don't know about the flange differences for SRA/IRS yet...but do know my IRS flange had to be swapped over to the P-71 DS..

Thanks that definitely helps. Do you know what the stock 99/01 cobra, Mach tr3650 yoke is? 26 spline? Or are you saying I can just swap in a 31 spine yoke and it will be fine (except more abuse on the transmission)

Ford Racing M-4841-A - Ford Racing Transmission Yokes - Overview - SummitRacing.com Found this 31 spline yoke 1330 but doesn't say the length.

 

[shurur]

31 spline...yoke length listed as 7.5" per the summit racing link below.

Ford Racing Mustang 31 Spline Driveshaft Yoke for Tremec T45, 3650, T56, & Tko M-4841-A - Free Shipping at LatemodelRestoration.com

Ford Racing M-4841-A - Ford Racing Transmission Yokes - Overview - SummitRacing.com


Let me try to find that 8.5" yoke...

 

[shurur]

ok skip the longer yoke...not such a good idea.

Twisted 31-spline driveshaft yoke... WTF? - Ford Mustang Forums : Corral.net Mustang Forum

You're going to hate me..but I'd look at having a shop CNC a 1" spacer for you...

 

[fastback brian]

the cobra t-56 was not 31 spline, cant use that yoke on a 3650.. I believe it was chevy 27 spline yoke...

 

[04Mach1Blurr]

ok skip the longer yoke...not such a good idea.

Twisted 31-spline driveshaft yoke... WTF? - Ford Mustang Forums : Corral.net Mustang Forum

You're going to hate me..but I'd look at having a shop CNC a 1" spacer for you...

Lol if its the case, of .5 inches less of the driveshaft yoke out of the trans, is that enough to worry? Using my stock yoke and flange, both with the hybrid u joint and the drive shaft spacer.?

the cobra t-56 was not 31 spline, cant use that yoke on a 3650.. I believe it was chevy 27 spline yoke...

Do you know what the 3650 is ,I thought it was 28 along with the t56? Thanks

 

[shurur]

The t56/45/3650 are 31 spline...
28 spline T-5 are foxbody.
Other T56 splines are GM trans.

2003-04 Mustang Cobra Aluminum Driveshaft by Ford - Free Shipping at LatemodelRestoration.com


You may be ok with it short, but the DS will be sliding around alot..1" - 3/4" is considered the right amount....Now I think that is because more "slop" than that is like the extended yoke problem....yet you need some for chassis flex (guessing).

IMO you really need to make up that 1" somewhere...and I'm not entirely convinced the spacers for the SRA won't work..I haven't looked hard, "researched" enough on that end of the DS..The pinion flange differences/subtleties.

Getting a spacer CNC'd probably won't cost much...just pull the pinion flange (mark position and note thread depth/count for reinstall later) and bring it to a shop.

 

[04Mach1Blurr]

Thanks I appreciate it, I do want to try my own thing as there aren't many people "fabricating" parts anymore. But what it comes down to is $13.73 more to buy the ready drop-in aluminum drive shaft off of American Muscle with the 6% discount code.

I think its absolutely plausible to do what I've researched, but after the research on parts and shipping it may not be totally worth it if I can get a brand new unit for ~$14 more.

What I want to look at now is the weight of the AM aluminum drive shaft in full compared to the cobra drive shaft in full plus the 11/16th spacer. I doubt its anything much. But what this does give me is the opportunity to use the cobra drive shaft down the road for a t56 swap if I wanted to do one. Thing is I am graduating college this May and doubt I'll have enough cash ready to do a t56 swap anytime soon.


Decisions decisions.

 

[fastback brian]

A 1 inch spacer may work..It wont change the angles much..
so you will end up with a 31 spline 1330 trans yoke , 1330/1350 adapter ujoint, 03-04 cobra d-shaft, 1350-1330 ujoint, 1330 yoke, 1 inch spacer, mustang gt 8.8 flange..
IF a spacer is to be made then go back to the large 03 cobra 8.8 pinion flange so you can use the good solid body 1350 u-joint, easier to get to the bolts too with the big flange., Even better to get a 1350 yoke for the 3650 and not use them hollow body 1330-1350 adapter u-joints..

 

[shurur]

A 1 inch spacer may work..It wont change the angles much..
so you will end up with a 31 spline 1330 trans yoke , 1330/1350 adapter ujoint, 03-04 cobra d-shaft, 1350-1330 ujoint, 1330 yoke, 1 inch spacer, mustang gt 8.8 flange..
IF a spacer is to be made then go back to the large 03 cobra 8.8 pinion flange so you can use the good solid body 1350 u-joint, easier to get to the bolts too with the big flange., Even better to get a 1350 yoke for the 3650 and not use them hollow body 1330-1350 adapter u-joints..

OK..there's the pinion flange answer..and I agree..then you have the beefy hook for that T56;-) someday.

This is a big topic amongst the 99-01 cobra folks...and an AL DS for our cars is considered an "Urban Legend."..There's even a thread with that title.

 

[shurur]

Thanks I appreciate it, I do want to try my own thing as there aren't many people "fabricating" parts anymore. But what it comes down to is $13.73 more to buy the ready drop-in aluminum drive shaft off of American Muscle with the 6% discount code.

I think its absolutely plausible to do what I've researched, but after the research on parts and shipping it may not be totally worth it if I can get a brand new unit for ~$14 more.

What I want to look at now is the weight of the AM aluminum drive shaft in full compared to the cobra drive shaft in full plus the 11/16th spacer. I doubt its anything much. But what this does give me is the opportunity to use the cobra drive shaft down the road for a t56 swap if I wanted to do one. Thing is I am graduating college this May and doubt I'll have enough cash ready to do a t56 swap anytime soon.


Decisions decisions.

There are little machine shops around..you just have to call around and talk people up.
And they will set up the machines for you..I bet someone could even sell a few of these spacers...

$$$$$$$$$$$$
That's why I did what I did (with my P-71 AL DS approach) And now I have the right fit for what I have now...and can get an inch cut later for my T56;-) But it will be 1330...

http://www.ebay.com/itm/Aluminum-Driveshaft-Ford-Police-Crown-Mustang-P-71-MINT-/320753055746


Sure you can buy the "j" (45.5") and squeeze it in...others have with supposedly no ill effects...I understand.

 

[agent-orange]

Is there someone, that had a alu ds installed on his 2001 Cobra? I bought one at Ebay, but it isnt a Terminator drive shaft, the guy bought it from Lethalperformance for 600$ and he told me, that I just have to change the flanges with the one from my stock ds. I acutally dont know the manufacturer of the ds, didnt see something on the ds, which would tell me, who the manufacturer is. Here is a theard from the seller, which I found: 99-04 Heavy Duty Cobra Aluminum Driveshaft

What do I have to do now exactly, that this driveshaft will fit in my 01 Cobra?

 

[bluebosss197]

I've been running my 03/04 T-56/driveshaft swapped 96GT with Terminator 1350 pinion flange on my SN95 SRA for over 3 years now with 2 inches of the original Terminator d/s yoke showing and I haven't run into any problems. I am not a high hp car though so I would not be so sure how well that would handle with a higher hp car.