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1/19/2019 9:36 AM  #1


Over drive

When I started this long drawn out process there wasn't a lot of option for the 71-73 mustangs out there. But as I now can see light at end of the tunnel I need to make one more change to make it a little more road friendly, Options are AOD, 4R70W, Gear vendors , Or swap to a five or six-speed manual , Currently a C_6 . The big thing is cost five speed conversion about 5400, based on quotes. Gear vendors unit alone 3000, Junk yard 4r70w about two -400 plus controller mounts flex plate drive shaft  . I am Leary of a  junk yard  tranny. Would love go stick but that is pricey . I know what ever I do is going to cost some coin. By the way Motor is 351w at about four hp four + ft pound torque. big question is there five that will handle the torque and not rack up 2500. Also rear gears are 3.55


If its worth doing do it right !
 

1/19/2019 11:35 AM  #2


Re: Over drive

I wouldn’t go gear vendors.  That was a good option 20 years ago, but now there are aftermarket transmission controllers that are so adaptable and reliable that I’d only consider going with a Baumann USshift controller on a modern automatic overdrive.  That is just me, once my car has returned to the street in a few years I plan on pulling the FMX and going OD with a Quick 4 controller or whatever better version of it exists down the road.

Or go manual...

The new automatic transmission controllers are pretty cool.  You can tweak several programs so that you can swap between them in the car on the Quick 4.  Have one program set up for the strip (even enable a transbrake), one with lower, softer shift points for the street,
Maybe an autocross program, with paddle shift.

 

1/19/2019 12:14 PM  #3


Re: Over drive

I and others here would recommend getting a 4R70W and a Baumman ($600)or such quality controller. Out here in Cali, you can get a rebuilt trans for 750-$900.


Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
 

1/19/2019 4:15 PM  #4


Re: Over drive

$5400 for a manual conversion?  I'm sure I did mine for about $2,000.  I wouldn't bother with a 6 speed.  The T56 is the only 6 speed worth using and its huge.  Likely doesn't fit in the stock tunnel.  They're also expensive to buy new or rebuild. 

The simplest solution is a T5 from a V8 Fox Mustang.  Its closest thing to a bolt in swap that exists.  There's no need to buy a new trans.  I've bought several used T5s in the last couple years and paid no more than $200.  Last one I bought had the bellhousing and a Pro 5.0 shifter for $200.  I would always rebuild the trans because I know how they got used, but the full rebuild kit is about $335.  351W might use a different bellhousing. 

Clutch, flywheel, crossmember, etc. all easily obtained for not a lot of coin.  The pedal situation would need to be looked into.  I don't know anything about the '71-'73 cars in that regard.  Run the Mustang Steve cable clutch conversion if available. 

 

1/19/2019 9:20 PM  #5


Re: Over drive

I would do the five speed. I converted my 66 using a 92 fox body trans and bellhousing. I used a stock flywheel and clutch set, a crossmember from Modern Driveline and a fastener set from Rosehill. I had the driveshaft shortened at a local shop. I have a 3:55 rear gear which is ideal. I think I have around $1000 in the project.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

1/19/2019 9:51 PM  #6


Re: Over drive

I went with a TKO 600 kit from Midern Driveline. It’s holdingnup well. If you go stick route with a T5, make sure it’s rated for the 400+ ft# of torque your gonna make.


John  -- 67 Mustang Coupe 390 5 speed
 

1/20/2019 6:39 AM  #7


Re: Over drive

In a street car there's really no need for a super strong manual transmission.  What it all comes down to is where the fuse is (i.e. the weakest link).  A street car's weakest link is always the tires.  You're not going to shock load a transmission enough to break it in a street car.  So the idea that you absolutely MUST use a Tremec because your engine makes over the 350 lbs/ft. rating of a T5 is due mainly to transmission companys wanting to sell transmissions.

Transmission strength ratings are arbitrary anyway.  The whole system of how they are rated is absurd.  Basically they shock load the trans in 1st gear until it breaks.  They then claim the previous torque applied (prior to the breakage) is its strength limit.  There's a lot of problems with this method.  First, I've rebuilt A LOT of T5s, you know how many times I've replaced a first gear due to failure?  How about never.  The test isn't real world because a street car, and even most race cars have some slip in the drivetrain somewhere that protects first gear enough to allow it to live.

Second, consider that the '93 T56 used in the F-cars had a 3.35:1 first gear.  '94-on used a 2.66 first gear.  The '93 trans is rated at 350 lbs/ft., whereas the later ones are rated at 450 lbs/ft.  Everything else is the same except for first gear.  The taller ratio simply put more leverage on the gear teeth and caused an early failure due to the testing methods.  Again, not real world by any means.

The T5 gets a bad rep, mostly because idiots can break anything.  I've repaired T5s from stock vehicles that were broken.  I've seen stock T5s live in 10 second drag cars.

So before you go off and spend over $2000 on a trans you likely don't need consider how you will really use the car.  Will the car ever see slicks?  Do you plan to powershift 3rd a lot?  If both answers are no then a T5 will work just fine. 
 

 

1/20/2019 8:18 AM  #8


Re: Over drive

TKOPerformance wrote:

Will the car ever see slicks?  Do you plan to powershift 3rd a lot?  If both answers are no then a T5 will work just fine. 
 

 
For my car using slicks, probable never. Poweshift to 3, almost every time I drive it. It’s like therapy!!

Folks will pick a HP / torque that they want and pick all the engine components to achieve that. Why shouldn’t the transmission, auto or stick, get the same thought process??


John  -- 67 Mustang Coupe 390 5 speed
 

1/20/2019 9:38 AM  #9


Re: Over drive

As most will never agree. It hard to beat the feel of a well tuned Toploader. 3.50 gearing and the Gear Vendor makes our 72 the best of both, a weekend racer, and hwy cruiser (2.72 in high range). Yes the GV is salty buy. I always plan that when the red car is gone, that the GV will be repurposed for what ever. There's a lot of GV in uses today, (motorhomes and diesel towing pickups). The GV are all the same, and hard to find used. Just my opinion. I rather be banging gears with my toploader, other's can bang what ever they want.

 

1/20/2019 9:43 AM  #10


Re: Over drive

I agree with TKO. Although torque and horsepower are certainly important factors to consider the intended use of the car and your driving style should also be considered. For example, a good friend of mine races a Facory Five Cobra with a modified 302 and a factory stock T5 with a 3:55 gear. He races on road courses and auto cross very competively which is to say he by no means baby's it. The T5 has been in the car for several years with zero problems.


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

1/20/2019 12:08 PM  #11


Re: Over drive

Its not about not giving the decision the weight it deserves.  Its about cost and overkill.  Think about it this way, would you put a forged 4340 crank in an engine that will only make 400HP?  You could, but its an expensive piece when a good quality casting will do the job just fine and likely never fail. 

I'll also add that the shift feel of the Tremecs is notoriously bad.  There is a way to remedy it, and people say once they are broken in they shift better, but the T5 shifts great because of its multi piece carbon lined synchros.  If you're used to driving a modern manual transmission the Tremec with its brass synchros feels clunky and unrefined.  The T5 style synchros are also used in the T56.  Basically modern manuals use ATF instead of heavy gear oil.  Brass synchros worked fine in a fluid that is hard to shear.  They don't work well in a fluid that shears easily (they don't hold well enough to decelerate the gears).  The multi piece carbon friction lined synchros were designed for use in ATF, and thus work very well.  A Tremec can be upgraded to the carbon lined synchros, but its an additional cost on top of whats already an expensive trans to buy. 

If you're not running slicks, but do plan on powershifting its considerably easier to make that shift successfully on a T5.  The issue you can have is that in 3rd gear you'll have traction most of the time, and you can shock load the trans enough to cause failure.  However, there are ways to prevent failure in the T5.  I'd start with a cluster support plate, which costs about $50 and can be installed without disassembling anything in the maincase of the trans.  I use them is every T5 I rebuild, and have for years. 

If you need more than that the T5 can still be a viable option.  For about the same cost as a Tremec you can upgrade the gears and mainshaft in a T5 with either G-Force or Astro parts.  These upgrades make the trans capable of withstanding 575 lbs/ft. reliably in a car on sticky tires weighing in at 3,500 lbs with an aggressive clutch.  Its another option worth considering.  I will be going that route with my '89 GT project, and have built several such T5s for others in years past.  Expensive parts, but very well made, very strong, and they retain the smooth shifting of the T5. 

Last edited by TKOPerformance (1/21/2019 12:06 PM)

 

1/20/2019 1:12 PM  #12


Re: Over drive

I agree , Why spend more than needed, It seems now that most everything is pricey ,  So how difficult is it to rebuild a T5  I tried my hand at a lot of things maybe its time to tackle something new.


If its worth doing do it right !
     Thread Starter
 

1/20/2019 7:41 PM  #13


Re: Over drive

Check out the tips and techniques for a T5 conversion article.  There  are a number of little items to consider that can up the cost.


Original owner - 351w,T-5, 4whl disks, power R&P
 

1/21/2019 5:53 AM  #14


Re: Over drive

There is both a book and a video available on rebuilding the T5.  Personally I don't think its that hard, so long as you lay everything out in the order it came apart, paying special attention to orientation.  There are probably 150 or so parts in a T5, but some of that isn't typically disassembled.  You won't take the shifting mechanism apart for example.  You will typically need a press, though I think I did a couple without one years back just using brass drifts, etc.  A press certainly makes it easier though.

I'd recommend checking out Hanlon Motorsports for parts and the video.  Here's a link:

http://cart.hanlonmotorsports.com/t5-5-speed

 

1/21/2019 8:39 AM  #15


Re: Over drive

 I can deal with cost and overkill. My main point is to choose a transmission that will live behind an engine capable of 400 + HP and torque and buy it once.

Here is some food for thought before you start buying parts and pieces
Depth of bell housing  - does it work with the length of input shaft?
Shifter location - Will it come up in the hole that Ford put in the car. If not, what will it take to make it work. Is moving the shifter around on the transmission an option or will a new hole need to be cut in the transmission tunnel? Is there a center console that will add to the equation?




 


John  -- 67 Mustang Coupe 390 5 speed
 

1/21/2019 8:59 AM  #16


Re: Over drive

TKOPerformance wrote:

There is both a book and a video available on rebuilding the T5.  Personally I don't think its that hard, so long as you lay everything out in the order it came apart, paying special attention to orientation.  There are probably 150 or so parts in a T5, but some of that isn't typically disassembled.  You won't take the shifting mechanism apart for example.  You will typically need a press, though I think I did a couple without one years back just using brass drifts, etc.  A press certainly makes it easier though.

I'd recommend checking out Hanlon Motorsports for parts and the video.  Here's a link:

http://cart.hanlonmotorsports.com/t5-5-speed

 
I don't know if they still offer it but a few years ago I downloaded an instruction book on rebuilding the t5 from Modern Driveline.

Last edited by BillyC (1/21/2019 9:00 AM)


"anyone that stops learning is old, whether at twenty or eighty"Henry Ford
 

1/21/2019 10:11 AM  #17


Re: Over drive

When using a Fox era T5 in a classic Mustang here are the answers:

1.) Use the Fox bellhousing and engine plate.  Literally bolt on parts.  I checked fitment and its fine on the 351 as well as the 289/302.

2.) The shifter comes up very close to stock.  A stock shifter would almost certainly work.  An aftermarket shifter with stops will not.  The trimming needed is fairly minor.  You won't be able to get the shifter off with the trans in the car, but IME that was hit or miss even in a Fox body.  I would highly, highly recommend running a Pro 5.0 shifter.  The stock shifter is like a breadstick in a bowl of noodles. 

You will need a flywheel for your engine balance, which is likely 28oz. imbalance, not the 50 oz. that the 5.0 used.  Flywheels are easily available and can be had cheap.  I bought a likely made off shore one for my '67 for like $100 that has worked just fine.  Ford Racing has an SFI one for like $270.  I'm using that on my '89, as my 331 uses the 28 oz. imbalance instead of the 50oz.  That car is going to be more of a street/strip car, so the added protection seemed worthwhile.  It may see sticky tires and/or nitrous at some point, so the expense was worth it IMO. 

Again, overkill is also no guarantee.  Give me a trans rated at 500lbs/ft. behind an engine rated at 350lbs/ft. and I'll find you someone who can break it.  Drivetrain strength doesn't deal in absolutes.  No one can say this trans will break immediately behind that engine, and conversely they also can't say this one will never break.  It all comes down to degrees of likelyhood.  I ran a side business rebuilding and building transmissions for years.  I never had a single trans come back from someone who followed my advice.  I built a half dozen Z-spec geared GM pattern T5s for use in 3rd gen F-cars, several of which went behind 383 strokers making every ounce of 500lbs/ft.  They went through tires rather quickly, but as far as I know going on 15 years now not a single one ever broke. 

If you really feel you must have a Tremec then go for it.  What I'm saying is I don't believe its necessary, and when cost is a factor a trans I can buy and fully rebuild for $600 sounds a lot better than a new one costing $2,000.  I'd rather save the $1400 and use it elsewhere in the car. 

Then there's using parts in a car for the way the car is being built.  I've seen guys build street/strip cars and both spend a lot of unnecessary money and create unnecessary inconvenience in the name of strip use when in reality the car spends 99.9% of its time on the street.  If you've got the money and don't care, hey, good on ya.  If you're on a tight budget though that overspending in non critical areas can be the difference between a driveable car and one that sits in the garage due to lack of the funds needed to complete it. 

 

1/21/2019 10:17 AM  #18


Re: Over drive

Here's a link off MDL's site on the T5:

http://www.mustangandfords.com/how-to/drivetrain/1506-everything-you-ever-wanted-to-know-about-the-t-5-five-speed/

Not exactly step by step like a manual, but the basic gist of the rebuild.  They don't walk you through setting endplay on the main and countershafts, which is crucially important.  You actually want a bit of preload when using a support plate.  This is best measured with a dial indicator, and you'll need calipers for measuring shim thickness. 

Last edited by TKOPerformance (1/21/2019 12:10 PM)

 

1/21/2019 7:06 PM  #19


Re: Over drive

check out, gearboxvideo.com

Really good vid's on the T5....from tear down and inspection to the rebuild.  He has video's on other trans as well.....

 

1/22/2019 6:25 AM  #20


Re: Over drive

Thanks to everyone for all the inputs. I find that this site gives the best information and in a friendly manner. After reading all reply's This is where i am at . I think it would be fantastic to rebuild a T5 limitations on that is equipment I do not own a press still checking contacts in my area for that. I have always found it is best if you can to build  or rebuild it your self. I will go some type of 5 speed,I have removed the pedal support and have started the pedal install. Next question is there a reliable builder that you can recommend , Most places need a core that I do not have, I guess simple solution go buy a t5 at a junk yard and some of them want core. Again thanks to everyone . 
  


If its worth doing do it right !
     Thread Starter
 

1/22/2019 9:04 AM  #21


Re: Over drive

You might try Glen at Rosehill Performance, Tomball Tx.  If he is able to take on the job he will absolutely make you happy.  Give him a call or leave a message, can't hurt and he might be able to fix you up.

BB


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

1/22/2019 9:25 AM  #22


Re: Over drive

Bullet Bob wrote:

You might try Glen at Rosehill Performance, Tomball Tx.  If he is able to take on the job he will absolutely make you happy.  Give him a call or leave a message, can't hurt and he might be able to fix you up.

BB

DITTO  I have had a Glen T5 for many years. He'll help you out with any info/issue even if you buy from someone else.  
 

 

1/22/2019 9:40 AM  #23


Re: Over drive

Bullet Bob wrote:

You might try Glen at Rosehill Performance, Tomball Tx.  If he is able to take on the job he will absolutely make you happy.  Give him a call or leave a message, can't hurt and he might be able to fix you up.

BB

   I have a Glen's rebuild T5Z in mine too and its worked really well. 
 

 

1/22/2019 10:26 AM  #24


Re: Over drive

I have a core and can rebuild it for you.  PM me to discuss further. 

 

1/22/2019 6:36 PM  #25


Re: Over drive

Glen's the best, my T5 is great ☝️


Life is too short to drive a boring car😎
 

Board footera


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