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Discussion Starter · #1 · (Edited)
Installing 2005-10 Mustang T5 5-speed into an Opel GT

Note: This is still a work in progress. More updates and photos to follow over the coming days.

I recently installed a Tremec T5 from a 2005-10 Ford Mustang (aka S197) into my Opel GT and wanted to document the process for others who may wish to do the same.

Most previous T5 installations into an Opel have used the earlier GM T5 transmissions from the Chevy S10, Astro van, Camaro, etc. These installations are well documented elsewhere, but to my knowledge nobody has installed the Ford S197 transmission into a GT until now.

Each version of T5 comes with its own set of issues that have to be overcome to successfully install them into an Opel. The S197 version is no exception, but it also has some advantages over the earlier GM versions:

All S197 T5s are World-Class transmissions, while most GM versions are not. Here's a good explanation of the differences. T5 History in Ford Mustangs with specifications for World class and non-World class T5's Modern Driveline

The S-197 T5 is shorter than the GM versions, meaning the driveshaft can be a little longer and thus easier to balance. The shorter tail-shaft also means it's less likely to interfere with the parking brake brackets in the tunnel.

It has better gear ratios than some of the GM versions, with their super low “granny” first gear.

S197 T5 vs Opel 4-speed gear ratios:
1. 3.75/3.43
2. 2.19/2.16
3. 1.41/1.37
4. 1.00/1.00
5. .73/na (2,700 rpm at 70 mph with my 175/70-13 tires)

The pilot shaft is the same length and diameter as the Opel 1.9, so no flywheel machining is required unless you want to use a larger clutch than the stock Opel 8” clutch. You can use the original Opel pilot bearing, pressure plate and throwout bearing. Only the clutch disc needs to be replaced to match the T5's10-spline input shaft.

The shifter location is nearly ideal to fit the shifter hole in the GT's tunnel.

It's newer, so should be easier to find in wrecking yards going forward. Rebuilt units are available for about 40% the cost of a rebuilt Getrag 240, though about 60% the cost of a Getrag is a better estimate after you get an adapter plate and everything else you need. You could probably save several hundred more dollars with a used transmission, but I opted to go the rebuilt route.

An adapter is now available from Hot Rod Works to mate this T5 to the Opel bellhousing. Cost at this writing is $270, though a minimum order of three units is required. More info below.

There are also a few disadvantages:

The S197 T5 installed in the Mustang used a Rube Goldberg series of linkages, aka the “remote shifter” to move the shifter location rearward. This itself is not a problem for us, as this linkage is not used when installing a T5 into a GT. Without the remote linkage, the shifter functions much like any other T5. The only issue is that the standard GM shifters and those from earlier Ford versions are a little different because the S197 T5 has a taller shift tower. This means that off-the-shelf T5 shifters, like those readily available on E-Bay, require some rework. More on this below.

The input bearing retainer will have to be changed with one from a mid-90s Ford T5 in order to use the transmission-to-engine adapter now available from Hot Rod Works. This is about a $50 part, but additional machining to allow it to fit the Opel throwout bearing cost me an additional $30.

The speedometer output is electronic, so either an expensive electronic-to-mechanical adapter or a GPS speedometer will be needed. For now I've opted for a $35 GPS device that sits on the dash.

Other differences:

The S197 version uses a flange rather than a slip yoke on the output shaft. This is not necessarily a problem, as you'll have to have a new driveshaft made anyway, but it means you'll need a driveshaft with slip joints in it. This adds some weight to the driveshaft. Ford Mustangs, Rangers and Explorers have used this type of driveshaft for several years, so the components needed to make your new driveshaft are readily available at wrecking yards.

Bill of Materials (costs are only what I paid, subject to change and your negotiating skills!):

Rebuilt S-197 T5 transmission. ($625 including shipping, from E-Bay seller gearking11). A local T5 guru tells me that this company is a well-known rebuilder. The transmission I received from them actually looked brand new and has worked perfectly. Note: As of this writing the price has increased to $695.

Adapter Plate. $270 plus shipping from Hot Rod Works in Idaho. Hot Rod Parts - Custom Hot Rod Car Parts. Ask for Ken Smith. Minimum order three pieces.

Drive Shaft. The front flange and slip joint came from an early 90s Ford Ranger, and the rear yoke came from an old Opel drive shaft. Phoenix Rack and Axle welded them together and balanced for $150, which included a new front U-joint. The rear yoke and U-joint were standard Opel 1.9. The Ranger driveshaft cost me $25 at a local Pick-n-Pull. New rear U-joint was $26 from OGTS.

Input Bearing Retainer. S197 T5's came from Ford with a hydraulic clutch, so the input bearing retainer (which in past also functioned as the throwout bearing guide) differed from earlier T5 versions. It's much thicker, and also eliminated the T5's built-in throwout bearing guide. In order to use the Hot Rod Work's adapter, the S197 input bearing retainer has to be replaced with one from a mid-90s Mustang, Ford Performance Part # M-7050-B. $51.99 from americanmuscle.com. Since this part acts as both the transmission input bearing retainer and the throwout bearing guide, the original Opel guide will not be needed. Unfortunately, Ford retainers are 1.43” diameter and GM retainers are 1.375”, same as Opel, so the Ford part will have to be machined down to fit. The tube will also need to be shortened by 9/16". So why not just use a GM throwout input bearing retainer/throwout bearing guide? Because they used a different transmission input bearing than our Mustang transmission. I had the Ford Performance part machined for $30. Perhaps there is a retainer that has both the Ford bearing and the GM retainer shaft diameter, but I haven't found it yet.

Clutch. I used the standard Opel pressure plate, throwout bearing and clutch fork. The clutch disc had to be custom made to fit the Ford 10-spline 1-1/16 input shaft. $170 from California Custom Clutches. http://californiaclutch.com. It works perfectly.

Shifter. I used the 83-04 Mustang/Thunderbird shifter. $28.98 on E-Bay. If I had it to do again I might try the Chevy S10 version, as I believe their shift tower is closer in height to the S197 T5's (not verified). Further details on the mods I had to make are below.

Transmission crossmember came from a 1982 Toyota Celica. $25 at the local Pick-a-Part. Early 80s Toyota pick up crossmembers looked to be similar. The Celica crossmember comes within about 1/4" of mating to the Opel's automatic transmission mounting holes. The rubber mount is a leaf spring eyelet bushing I had leftover from replacing them in my 1972 AMC Javelin. Any round rubber bushing that is the right height and diameter would work.

GPS Speedometer w/ Heads-Up display. $35 on Amazon.com

Total cost: $1,436.97

S197 T5 alongside the Opel 4-speed:



More details and photos to follow.
 

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Discussion Starter · #2 · (Edited)
Here's the T5 with the HRW adapter attached. Note the height of the shift tower, which is taller on the S197 version of the T5. Fortunately, it does not bump into the transmission tunnel when installed with the recommended 6 degree down tilt.



Installing the T5 into the Opel is fairly straight forward, but the transmission, adapter plate and bellhousing (with throwout bearing attached) have to be installed as a unit because the throwout bearing guide is attached to the transmission, unlike the original Opel setup where the guide is attached to the bellhousing. It would probably be easier to drop the engine, attach the transmission, and re-install, but it can be done with the motor in the car. My car has a header, and the collector got in the way of the bellhousing when raising the transmission. Removing the exhaust header would seem to be the logical choice, but I did manage to do it by myself with the header in place, without a lift, using a transmission jack and two floor jacks.

Before you get to that point though, you're going to need to do some work on the shifter. This rod and part of the Mustang's remote shifter mechanism needs to be removed from the shift tower as it will not be used in our Opel installation.



In its place, we're going to put a pre-2005 Mustang shifter, but the heavy aluminum base needs to be cut down to fit inside the shifter tower. Here's how the shifter looks when used in the pre-2005 Mustangs.



And here's how it looks after cutting the base down to fit inside the shifter box. This is necessary because the S197 T5 shift tower is taller (and smaller) than that used in the pre-2005 Mustangs. Instead, we have modifed the thin metal plate that covered our T5's shift tower, and placed it between the base and the top aluminum ring. Holes have been cut in it to match the top of the shifter base. Hopefully you'll manage to do a cleaner job of cutting the top plate than I did. Note that I ended up inverting the top plate after this photo was taken (indented part should face down instead of up, as per the pictures in the next post.)

EDIT: Cut the base and fabricate the top plate so that the shifter is perfectly vertical when in neutral. If it's off center that means you're too far to the front or back, and you'll have trouble with the transmission popping out of either the 3rd and 5th or 4th, depending on which direction the alignment is off. Ask me how I know! I'm going to fabricate a new top plate and will try to remember to post the dimensions when I'm done so as to take the guess work out of this.




Here's what the shift tower looks like with the remote parts removed. The ball of our shifter will fit into the socket you see at the bottom of the tower. Note I have plugged the now unused hole at the front of the shift tower with a rubber cork to keep transmission fluid out of the shift tower.

 

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Discussion Starter · #3 · (Edited)
And here's the sequence we've followed to place our shifter into the tower. The white rubber piece at the front of the tower was there just to stop the base from moving around. It was later removed as the rubber cork does the same job. In any case, once everything is tightened down it doesn't move, but I found the base needed to be positioned towards the rear of the shift tower while tightening the screws down.





I found that if you tighten everything too tight, the shifter gets too stiff. Better to just snug the small allen head bolts and put some lock-tight them. The large allen heads are for adjustment of the shifter tension springs. I wouldn't put lock tight on those!

Figuring out the shifter was the hardest part of the job, but I've driven about 1,000 miles with it so far and it seems to be holding up.
 
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And here's the sequence we've followed to place our shifter into the tower. The white rubber piece at the front of the tower was there just to stop the base from moving around. It was later removed as the rubber cork does the same job. In any case, once everything is tightened down it doesn't move, but I found the base needed to be positioned towards the rear of the shift tower while tightening the screws down.

I found that if you tighten everything too tight, the shifter gets too stiff. Better to keep the screws a little loose and put some lock-tight on all of them.
Looks like maybe you could make 2 aluminum parts that would bolt to the 4 bolts in the shifter tower that would replace the two stop screws that you put in. You would be able to create a horizontal smooth continuous surface that would stop the shifter when it is off center instead of the edge of the bolt and avoid wear on the shifter shaft over time.
 

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I found that if you tighten everything too tight, the shifter gets too stiff. Better to keep the screws a little loose and put some lock-tight on all of them.
Try shims to raise the shifter tower a little bit and you may relieve the binding and then be able to tighten all of the bolts properly.
 
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Discussion Starter · #6 · (Edited)
Driveshaft

As previously mentioned, the driveshaft was constructed using the front part from an early '90s Ford Ranger and the rear part from an Opel GT. Since the S197 T5 does not have a slip yoke, it had to be incorporated into the driveshaft, as many RWD Ford products have been doing for quite a few years now.



The new drive shaft measures 12.75" from center to center of the U-joints. Any time you change the transmission from what originally came with the car, you'll need to rethink your driveshaft and u-joint angles, and this is especially important with such a short driveshaft.

When I first installed my T5, I had vibration issues. The normal way to set driveline angles is to have the transmission and pinion angles the same an parallel to each other. In other words, if your transmission is pointing down (towards the rear) by 6 degrees, your pinion should be pointing up (towards the front of the car) by 6 degrees. Unfortunately, this is not possible in an Opel GT as the torque tube is factory set to about 1 degree up. You can add some washers to the front of the torque tube mounting tabs to point it down, but up is not possible without some major cutting and other modifications to the floor pan.

While the parallel method is the accepted practice, it is not the only way. My driveline shop recommended that I try pointing the torque tube down. This seemed backwards to me, but then I remembered reading somewhere about intersecting (rather than parallel) driveline angles. This is done mostly on big trucks and farm equipment, but some automobiles have come from the factory this way too, most notably some Studebakers and Land Rovers. This means you could have say three degrees down on your tranny and also three degrees down on your pinion and the vibrations would still cancel each other out. It's known as the "broken back" method. The disadvantage of this method is that the angles vary front to rear with suspension travel, whereas with a conventional (parallel) setup the angles are always the same, though they do increase with suspension travel.

I also discovered that while you ideally want the same transmission and pinion angles, the U-joint operating angles are what's really critical, especially in our short-driveshaft car.

This from the Spicer web site:

"Spicer has developed guides for u-joint operating angles. Keep the true angles less than 3 degrees if possible. Three-degree operating angles do not produce vibrations severe enough to cause damage. Keep the angles on each end equal within one degree. When the angles at both ends are equal, they cancel out the torsional vibration that is generated at the drive end of the driveshaft. Never assemble a driveline so that both ends are exactly the same. The roller bearings in u-joints must have a half-degree difference in order to rotate.

As you adjust the operating angle of the u-joint (by lifting the vehicle, shimming the rear axle, etc) you are also changing the elliptical path that the u-joint must travel in. The greater the operating angle, the less like a circle the path of the ellipse, and the greater the torsional vibration caused by the u-joint. It is for this reason Spicer recommends an operating angle of less then 3 degrees for a u-joint, a very conservative number."


Spicer has a very handy driveline angle calculator, and it quickly showed me what was wrong. I had an 8 degree front u-joint angle with zero at the rear!

http://spicerparts.com/calculators/driveline-operating-angle-calculator

I had been trying to raise my transmission, thinking the T5 sat low, but when I did this my driveshaft angle went from near level to 7 degrees in a hurry. So what I did was remove the transmission crossmember and put a floor jack under the transmission. By raising and lowering the jack I could then measure the various angles, plug them into the Spicer tool, and see what affect it was having on U-joint operating angles.

Everything is a compromise of what's possible given what you have to work with, but what I ended up with was 5.9 degrees down on the transmission and 1.0 degrees down on the pinion (dropping the front of the torque tube by adding washers), which gave me a 3.9 degree down driveshaft angle. The Spicer tool showed that this put the u-joint angles less than 3 degrees front and rear and within 1 degree of each other.

In short, try for 6 degrees down (on the engine and transmission (on a 1.9 CIH you can measure from the top of the valve cover), and one degree down on torque tube (front of torque tube pointing down) and your U-joint angles should be acceptable and vibrations minimal.

More to come....
 
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Discussion Starter · #7 ·
Try shims to raise the shifter tower a little bit and you may relieve the binding and then be able to tighten all of the bolts properly.
Good idea. Length of the rod is critical to proper shifting. That's why I inverted the top plate. Perhaps a GM shift rod would be an option too.
 

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Forgot to comment on one thing before. I think you can do a much better job of plugging that hole instead of using a rubber cork. If you can't tap it for a threaded plug then have an aluminum plug with a very slight taper made that you can drive in. That cork will not stay there!
 

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Good idea. Length of the rod is critical to proper shifting. That's why I inverted the top plate. Perhaps a GM shift rod would be an option too.
Start out using a couple of sets of feeler gauges as shims until you find the correct amount and then make a full shim out of brass stock.
 

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Discussion Starter · #10 ·
Looks like maybe you could make 2 aluminum parts that would bolt to the 4 bolts in the shifter tower that would replace the two stop screws that you put in. You would be able to create a horizontal smooth continuous surface that would stop the shifter when it is off center instead of the edge of the bolt and avoid wear on the shifter shaft over time.
The bolt stops came with the shifter, but I'm told that they're not really needed as current T5 supposedly have internal stops. In any case, I have them set so that there's about 1/4" clearance between the shifter and the stop when in the middle gears.
 

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Discussion Starter · #11 · (Edited)
Forgot to comment on one thing before. I think you can do a much better job of plugging that hole instead of using a rubber cork. If you can't tap it for a threaded plug then have an aluminum plug with a very slight taper made that you can drive in. That cork will not stay there!
It's a very tight fit once the base is in. I doubt that the cork is going anywhere. Also, it appeared there are bearings in there that the (now removed) remote shift rod rode in, so that would interfere with a threaded tap. Perhaps they were just lubrication holes... I didn't inspect them that closely, but in any case I wouldn't want to run the risk of getting metal shavings inside the transmission. Might be an option if the transmission were already apart.

EDIT: Perhaps something like this of the right diameter might be a better solution for some.

https://www.shawplugs.com/product-p/52406.htm
 

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Discussion Starter · #12 ·
Start out using a couple of sets of feeler gauges as shims until you find the correct amount and then make a full shim out of brass stock.
Could even incorporate it into a nice machined top plate. I was experimenting and figuring it out as I went and had considered having a nicer plate made once everything was proving reliable.
 

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Thanks and Great job..... I'm going to print it out and let my son see if it is a project he is willing to help me with..... He's a BIG Ford Fan so it is a possibility
 

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Discussion Starter · #14 · (Edited)
Input Bearing Retainer/Throwout Gearing Guide

The first photo is the input bearing retainer that is normally attached to the S197 T5. The second photo is the Ford Performance M-7050-B as used in pre-2005 Mustangs. As you can see, the latter includes the throw-out bearing guide, while the original S197 retainer is meant for a hydraulic throw-out bearing. The S197 retainer will not fit the HRW adapter, so you'll need to use the pre-2005 retainer in any case.

Note from the photo that Tremec changed the bolt pattern, so only three of the four holes line up and you will need to drill the fourth hole. Other than that it's a quick change. You'll also need to check the end-play of the shaft with the new retainer and add or remove shims as necessary. The T5 manual provides instructions on this. My transmission did not require any shim changes.

The bearing is the same with either retainer, the S197 pilot bearing is the same as the Opel, and the 1-1/8" thickness of the adapter plate compensates for the added length of the input shaft vs the Opel 4-speed. No input shaft or flywheel changes are needed. However, the shaft of the retainer will need to be shortened by 9/16" and turned down to 1.375 diameter. You can then use the Opel throw-out bearing, pressure plate and clutch fork.

Note that Ford throw-out bearings are flat-- meant for pressure plates with "bent" fingers-- while the Opel pressure plate has flat fingers that require a rounded front surface on the throw-out bearing. Use of a Ford throw-out bearing is therefore not recommended.




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Discussion Starter · #15 · (Edited)
Clutch

Opel clutch disc on the left, custom disc from California Clutch on the right. More or less the same except for the splines and shaft diameter. I was unable to find an 8" clutch with a 10 spline 1-1/16 shaft, hence the custom disc. You might save some $$ if you can find an off the shelf disc somewhere.

Make sure to adjust the stud on the clutch fork arm to the correct 4.25 inches from the engine mating surface per the original Opel instructions. Do this BEFORE you permanently attach the adapter plate as you can't access it afterwards.

The clutch works flawlessly for me with the new disc and the T5 input bearing retainer.



More to come...
 

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Great Modern Transmission

Keep up the updates. This is great. I will be doing this exact same conversion. To me its much better then the Getreg due to the parts availability and the torque it will handle. I have had a Saleen Mustang since 2005 and its a great transmission. Never any problems even holding the power of the Saleen. I think I would like to use the bigger S10 type flywheel conversion instead of the Opel stuff though.

If others are interested we should do a mini group buy and get the adapters.
 

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I'm installing a getrag, but for a good price I'd buy the T5 adapters "just in case".
 

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I'm installing a getrag, but for a good price I'd buy the T5 adapters "just in case".
Since I designed the adapters, I think I have first crack at making a handful of them.

My concern is that there appears to be two sizes to work with.

Zippy's recipe appears to be tried and true. The other one is yet to be determined.

I thought about making a run of the GM t-5 adapters. I know those work.
 
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