Automatic Transmission???

[lastdime]

I have injured my clutch foot and don't know if it will be able to heal enough to press the hydraulic clutch pedal again. I am considering modifying my MK4 to an automatic with manual shift transmission. I would appreciate information and recommendations as to the pros and cons of doing this. Obviously expense is a big one, but what about the availability of these transmissions and their installation? Is the conversion difficult? What does the process entail?

I would appreciate any help from you guys.

Thanks,

Mark

[Smiley]

I too have leg issues so I purchased a crate 427 stroker with a 4R70W auto transmission as a package from Blueprint.
I purchased it as a crate combo because I didn’t want any finger pointing down the road if something didn’t work.

That being said, although I haven’t tried to fit it yet, I measured everything and it looks like it should drop into my coupe motor mounts and transmission mount as delivered.

I think the biggest challenge with a homebrew is getting the proper torque converter for such a high hp low weight car.

Good luck.

[FLPBFoot]

I can't talk to a conversion but just dropped a BluePrint 302 with 4R70W into the wife's MKIV. Dropped is not the proper term....stuffed is more like it. It is tight and I had to remove several ears off the trans as well as part of the backing plate by the starter. Also a rib on top of the trans that hits the cross member at the back of the engine bay. Also the TransStar 4R70W requires a oil cooler and the outlets are right up against the passenger footbox. I need to "massage" the footbox metal a bit to allow room for the 6AN elbows and the tubing to run up front for the cooler.

Also, you'll need to likely modify your driveshaft. The 4R70W uses the same 32 spline output but the needed yoke is larger in diameter for the 4R70W than a TKO or TKX. I got the larger diameter yoke and replaced it with the supplied one from FFR.

Good luck. I should have this thing in gocart by Thanksgiving. The 302 dyno'd at 380hp so should be plenty peppy.

Steve

[lastdime]

Steve, that is helpful. I had to do quite a bit of "massaging" in the engine bay to shoehorn my 460 SCJ into the limited space. I fully expect the transmission to be of a similar challenge.

[lastdime]

Smiley, I appreciate the observation on the torque converter. I have a 460 SCJ engine, 550 hp and 524 Lb.Ft. of torque so I will need to be careful in my selection.

Thanks

[Blitzboy54]

FFR suggests 3200-3400 with the weight of the car being what it is.

As far as the difficulty of the conversion is in the eye of the beholder. I know dropping the transmission out from underneath is doable but cumbersome with the 4" tube in the way. You have to rotate and tip it to get it out. Question is then does an automatic fit back in the same way. I don't know and I don't imagine many folks do. If it doesn't you are on to option 2

Which is to have to pull the engine out from the front. This would be the easiest in that you know in advance what the work will look like but it's certainly more work. I think this is how I would do it. I think no matter what your going to need a different drive shaft.

So I live in Niskayuna and I would absolutely be happy to come help you over a weekend or 2 pull the engine and swap it into an Auto. DM me, I love an adventure.

The third option is batsh** crazy and thats cutting out the 4" cross member and then welding it back in when your done :)


**Edit** are you in NY or Wyoming? Cuz that will definitely impact my availability. lol

[Smiley]

I plan to use a Lokar electronic shifter and an HGM paddle shifter. Both are compatible with the transmission controller that Blueprint used for my crate combo.

[Shamilton289]

Interesting thread! My knees aren’t what they once were. I’ve had several stick shift vehicles…SVO Mustang, 66 Mustang, Fox Mustang, Ranger pickup…but I’m leaning strongly to a C4 behind my 289. I’m building a spirited cruiser, not a track car.
Wondering if I should consider AOD, but I already have a C4.

[Hellion]

Wondering if I should consider AOD, but I already have a C4.

For years I was a manual transmission guy for all of my play cars but then I got older and just wanted to get in a drive without shifting. :rolleyes: I have an AOD with a Lokar shifter in "Rosie" which replaced the T-5 and like it. If going that route, I recommend installing the lightweight governor counterweight and related spring from a TransGo AOD-Hi-Rev Governor Kit (https://www.ebay.com/itm/255735847735?chn=ps&_trkparms=ispr%3D1&amdata=enc%3A12CIDWyeHTAuevZMQymYhBw1&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=255735847735&targetid=2320274087935&device=c&mktype=pla&googleloc=9015255&poi=&campaignid=21404617128&mkgroupid=173029507108&rlsatarget=pla-2320274087935&abcId=9450159&merchantid=263811753&gad_source=1&gad_campaignid=21404617128&gbraid=0AAAAAD_QDh9W77zHIvR6H3RZrsmBLe9ow&gclid=Cj0KCQjw_L_FBhDmARIsAItqgt5EXNlitYYjRLy6JTxM qxTrjjrAbqan6lTLfkAgEC9rR9nWZGkNS8AaAvIBEALw_wcB) to eliminate the quick shift points and make the car drive more like it has a manual transmission. I did not install the valve body springs in the kit which are not necessary IMO. I have done this procedure in other AODs that I have had in the past as part of the upgrade process.

I have a C-4 in my '65 Mustang Fastback (Ruby) and love it - BUT - she has 3.25 gears. With that said, and depending on your rear end gears and driving habits, a C-4 is lighter and easier to install which may meet your needs.

[Smiley]

Also, you'll need to likely modify your driveshaft. The 4R70W uses the same 32 spline output but the needed yoke is larger in diameter for the 4R70W than a TKO or TKX. I got the larger diameter yoke and replaced it with the supplied one from FFR.

I thought the 4R70W was a 28 spline?

[FLPBFoot]

I thought the 4R70W was a 28 spline?

Sorry Sir.....YOU ARE CORRECT!!. 28 spline. This is the yoke i purchased: Spicer 2-3-14061X Slip Yoke. I am running a IRS and this yoke went right into the u-joint and when bolted up there is about 1/2" of the shaft showing. Works perfect.

[PG_Cobra]

I switched my MK1 T5 to AOD a couple of years ago, in my case it was a foot issue needing wide shoes that made me ditch the clutch pedal. The AOD is a tight fit but doable, same length as the T5 so the drive shaft works. I have a stock 302 HO (89) with 3.55 axle so not overpowering the transmission. AOD came from a 93 Mustang GT. I rebuilt it and added a PA aftermarket VB. I did have valve body issues with shift points, (long story). Dan at Silver Fox just reworked my VB and fixed everything. If you are going AOD and intend to buy a rebuilt tranny I'd recommend going with Dan at Silver Fox, he understands Factory Fives and he's also one of the best in the industry.

[Shamilton289]

For years I was a manual transmission guy for all of my play cars but then I got older and just wanted to get in a drive without shifting. :rolleyes: I have an AOD with a Lokar shifter in "Rosie" which replaced the T-5 and like it. If going that route, I recommend installing the lightweight governor counterweight and related spring from a TransGo AOD-Hi-Rev Governor Kit (https://www.ebay.com/itm/255735847735?chn=ps&_trkparms=ispr%3D1&amdata=enc%3A12CIDWyeHTAuevZMQymYhBw1&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=255735847735&targetid=2320274087935&device=c&mktype=pla&googleloc=9015255&poi=&campaignid=21404617128&mkgroupid=173029507108&rlsatarget=pla-2320274087935&abcId=9450159&merchantid=263811753&gad_source=1&gad_campaignid=21404617128&gbraid=0AAAAAD_QDh9W77zHIvR6H3RZrsmBLe9ow&gclid=Cj0KCQjw_L_FBhDmARIsAItqgt5EXNlitYYjRLy6JTxM qxTrjjrAbqan6lTLfkAgEC9rR9nWZGkNS8AaAvIBEALw_wcB) to eliminate the quick shift points and make the car drive more like it has a manual transmission. I did not install the valve body springs in the kit which are not necessary IMO. I have done this procedure in other AODs that I have had in the past as part of the upgrade process.

I have a C-4 in my '65 Mustang Fastback (Ruby) and love it - BUT - she has 3.25 gears. With that said, and depending on your rear end gears and driving habits, a C-4 is lighter and easier to install which may meet your needs.
I have a 3.27 rear gear ��

[wallace18]

Here is build thread of the last MK4 I built. Came out very nice. 1st MK4 with Auto I did.

https://thefactoryfiveforum.com/showthread.php?47283-CM-s-MK4-build-by-Wallace18

[CraigS]

As you plan the change think about resale. I know, hate it, but someday it will happen. My thought is leave the pedal box you already have. Maybe the clutch pedal could be moved to the floor and secured to use as a dead pedal foot rest. Maybe it can be removed. Either way make it easy as you can for a next owner to convert back to a stick.

[Hellion]

I have a 3.27 rear gear ��

Oops - I meant 3.20 - Mustang has the period-correct 8" rear end. Since your gears are similar to mine in the Mustang, you'll experience 3,000+ RPMs driving at highway speeds which does limit top end speed. I rarely go over 80 mph in the Mustang cruising on the highway whereas I have exceeded 100+ in the Cobra every now and again depending on traffic and where I'm driving. :rolleyes: Obviously, both cars provide a completely different driving experience. If you don't want to limit your top end speed, go with the AOD like I and others have if that's what you choose.

[Hellion]

As you plan the change think about resale. I know, hate it, but someday it will happen. My thought is leave the pedal box you already have. Maybe the clutch pedal could be moved to the floor and secured to use as a dead pedal foot rest. Maybe it can be removed. Either way make it easy as you can for a next owner to convert back to a stick.

Agreed. I converted my clutch pedal into a foot rest.