Hey gang..
As most of you know, I chose the GearVendor option for an overdrive system for my Daytona. Well, I began the installation process and would like to document my experiences.

Vehicle: 1969 Charger Daytona
Tranny: 727 Torqueflite
Differential: 9.75 Dana (4.10)
GV unit: Model 3D0727

1. Here's the basic/components I received with the kit



1. Raise/secure vehicle and remove driveshaft




2. Position jack/support under transmission. I used the tranny pan with a scissor jack with a block of wood



3. Remove tranny rubber insulator and crossmember ( I didn't remove insulator from crossmember)



4. Place drain pan under tranny and remove inspection plate that covers tranny housing snap-ring



5. Disconnect/remove trannyspeedo gear assembly from tailshaft housing



6. Remove six bolts securing tailhousing to transmission



7. Use snap-ring pliers to spread snap-ring while pulling tailshaft housing off.



8. Clean gasket surface on tranny



9. Remove original lock pawl assembly out of original tailshaft housing and install into new GV tailshaft housing. Also remove the snap-ring and install it into the new GV unit.





10. Install GV tailshaft housing onto tranny tailshaft. I utilized two exhaust manifold studs to hold the new gasket in place to help with the GV tailshaft housing installation. Worked out great. Once a couple of the original bolts are installed, you can remove the studs.




11. On my Daytona, there was a TTI exhaust system. The center h-pipe clamp was positioned with the nuts towards the back. This created a forward movement obstruction for the tailshaft housing. Simple solution was to reverse the clamp.





12. Install snap-ring cover gasket, cover and crossmember. Also, in my case with a center console, install the shifter rod bracket.




13. Verify the coupler is seated fully forward touching the tailshaft. Lightly grease the outside of the coupler, bushing, seal then slip the coupler back into the tailshaft housing. There shouldn't be any binding. The coupler is positioned in the housing for shipping purposes. Adjust the end play. I accomplished this by utilizing a straight edge, slipped two of the numerous supplied shims between the coupler and straight edge and then taking a measurement. I ended up with .013 clearance. The tech at GearVendor told me this was a proper technique and have a tolerance between 0 - 0.15. Do not place grease in the coupler to hold shims when reinstalling. This will compromise the end play reading. The shims are to be installed into the coupler on the tailshaft side, not the overdrive unit side.



14. Unfortunately, the clearance issue that "supposedly" was fixed, isn't. The speedo assembly typically was the culprit, but this, for me, was an issue of the overdrive housing. So, yes, I "made" room. I took my pickle fork since it has a solid round handle and use it with a sledgehammer to curve the floor pan inwards. It worked out great I do have to say. It made a nice smooth modification. The white grease pencil markings are the areas that were touched by the overdrive unit. I also ground down the two areas of the overdrive unit that touched the floorpan. I basically rounded down the peaks of the unit.






15. Install overdrive gasket with lettering facing tailshaft housing.



16. Slide yoke onto shaft of overdrive unit and then position unit onto housing.







17. Secure overdrive unit with the eight 1/4 20-inch locknuts/washers

18. Install supplied speedometer cable adaptor.



19. Install signal generator to cable adaptor then vehicle's original speedometer cable to signal generator.



20. I used a cable loop to secure the speedo-adpator and solenoid harness. Had to do this to keep wires away from h-pipe.



21. Driveshaft modification. Based on the dimensions, I had to shorten my driveshaft 14". I used on of my spare driveshafts, but unfortunately, the inner diameter (ID) of the driveshaft won't facilitate the installation/welding of the foreard yoke. This yoke was to be a match for the GV supplied driveshaft tranny yoke. So, I had to have the driveshaft service company make one from scratch. This will probably be the case for most Mopar driveshaft modifications. I got new u-joints and the assembly high-speed balanced. Brought it home, but unfortunately, the dang thing was about an 1" too long !!!! So, I'll have to take it back Monday.. Bummer, I was hoping to have it installed this weekend.

21a. original driveshaft measurement. I used a spare 727 I had for the measurements with my original driveshaft. Length to centerline of u-joint (21.5")




21b. GV complete unit (35.5")




21c. At the shop




21d. About an inch too long.. :'(



22. I mounted the electronics behind the kick panel. It fit rather nicely to be honest.



23. I decided I didn't want to permanently mount the selector switch and status light. I made a plate and attached it to the vent box under the dash. That way, the velco adhesive wouldn't be on the vent box. From what I gather, most driving will be in the "auto" mode, so there will not be a need to change the selection switch numerous times.



24. Here's the kickpanel back on. Would never know the electronic autodrive control box is back there. Also, the wire you see is the foot switch. Instead of mounting it on the floor, I'm going to place a toggle switch inconspicuously under the dash.



What I have to do now is fill up the overdrive unit with Dexron II ATF. Never use synthetic or additives. After that, replace the exhaust flange-to-manifold gaskets and get the driveshaft fixed.. After which, test drive time..........

Update: Jan.07, 2011


25. OK, got the driveshaft back from the shop. The dimension they needed was 40" from GV overdrive unit output seal to forward most portion of the yoke going into the differential.



26. Next is filling up the GV unit with Gear Lube. Here is the access/fill hole.




27. Here I'm finishing up with the fluid.
Edit: GV's update on fluid is either GM# 12346190, or Mopar #0487-4459, I will update the picture........ I used the Mopar brand. It is Gear Lube, clear



28. Pump works pretty good - The ATF was installed, then removed when I discovered through and GV update I needed to use the previously mentioned Mopar Gear Lube


I'll continue this later on this weekend, I have Guard Duty this weekend, so won't be able to mess around with it much...

Hope this helps anyone in the future with a GV install. Update: Jan.07, 2011

Awesome documentation. Thanks for posting as I am considering doing the same to my 1970 Roadrunner.

Step 25....Pack up and save all original parts.

Nice pictorial, thanks for posting.

What is the purpose of the 'foot / toggle' switch ?

is this system fully automatatic operation with no input for the operator ?

does the original speedo drive gear get transfered to this new unit ?

So, the system doesn't kick down, aka out of overdrive on accel ?
I assume the regular trans still does, so technially the trans is in 2nd , yet the OD is still engaged.

Is this unit capable of that kind of torque?

Great pics and article !! The unit can stand a crazy amount of HP...Something like 1200...I did the conversion to one of my vehicles a few years ago during the moparts group buy and it's still working like a champ with untold holeshots behind a 500 HP engine...Definitely a worthwile investment...

Great documentation... That is a long term plan for my 66 Satellite project. Perhaps the MOD's will place this in the Tech archives as it is good info for future reference...nice and complete install too I might add....

Nice documentation and pictures. I paid close attention as I have a unit that I have not installed yet but plan to before winter is out. One thing you did not discuss and I am concerned about is the angle the universal joints end up at when the driveshaft is shortened.Did you do any before measuring of the angles so you would have reference material for when you get the drive shaft in.
Happy New Year
Ross

Thanks Troy.......I will keep an eye on this for when you get the shaft back. I was lucky enough to win mine at Drag Week this year. Rick Johnson and all the staff at Gear Vendors are super people.

I am the only person in the UK to blow one of these GV overdrives up. The overdrive was 18 months old and fitted behind the 4 speed in my Road Runner. I emailed GV and Rick Johnson phoned me up almost immediately. He arranged a warranty repair using Overdrive Repair Services in Sheffield and sent them a new clutch and clutch band overnight to fix mine. I had it back in the car within a week. Customer service is second to none. Heres the switch I made for the pistol grip to operate the overdrive.

Good question and one that I'm sure every GV installer was pondering... ...IIRC The manual wants the final angles no more than 1.5-2 degrees{nose down} which is way different than the guidelines everyone is using in performance applications...I ended up setting mine up at 2.5 and have'nt had any cruizing or acceleration vibrations.... ....Technically, the addition of the unit is'nt changing the relationship between the trans and rear....But the shorter drivshaft is changing the working range of the universal joints through their range of motion....Also note the new yoke supplied...The one in my kit is a 1350 piece so it's plenty beefy...

I also have a Gear Vendors project coming up. Thanks for the writeup and I to am interested in any technical issues you have with the driveshaft angle. (If you have any)

Took the driveshaft back today to get it shortened. They asked for the measurements from the opening of the output shaft area/seal of the GV overdrive unit to the front face of the input yoke to the Dana. It measures 40". So, I'm taking that this will be the over all length with the extra needed coming from the distance of the u-joint as it slides into the rear Dana yoke, which will be about an inch. That would leave plenty of meat of the forward yoke in the output shaft hole of the GV unit and enough to slide back and forth as needed under driving conditions.....

Those GVs are bullet proof , had one on the 68 charger , stripped the planetries out before the box got hurt , 4400lb charger constantly put through it's paces @ the track , only issues i had was a control module go bad , GVs sent me one out within a couple days , great aftersales service.................nice work there MickRR.

Maybe I missed it but what supports the unit other than the crossmember?

When I put mine in my Challenger, I slid the new yoke in till it bottomed out. Then slid it back out 5/8 of an inch, and measured from center to center on the u joint holes of both yokes. Took that measurement to the driveshaft shop to get the new driveshaft made. The electronic box seems to be the weak link of the system. Check with the GV tech dude to see if yours will live behind that kick panel. Might build too much heat.

After I had a control box fail, I ran a spare wire from the foot switch down to the solenoid on the unit. I crimped an end on it, and then just taped it up and left it loose. Did the same at the foot switch end, and also ran a spare to the fuse block to supply 12V to the foot switch. All the solenoid needs is 12V to operate, so I can still get the OD to engage if the box ever takes a dump again. The split shifting was fun for the first 5 minutes, but I just use mine for OD now! Good luck, and you did a super nice job on the install.

Memories of installing mine...I had the same problem in the tunnel with the fitment of the OD unit. Still though, I hate working on transmissions and rear axles. The instructions were simple, easy to read. Took me 6 hours to install on a Saturday plus the waiting of a business day following for the driveshaft work.

Only problem I have is that my H-Pipe sits right on the GV unit where the finned part of the housing is. My exhaust melted the gasket. I still haven't gotten around to relocating the crossover. I have bought 2 spare gaskets just in case.

Only think I can't figure out is the split shifting. 1st (Gear 1), switch (Gear 1.5).....switch/2nd (Gear 2), switch (Gear 3).....switch/3rd (Gear 3.5 / OD)....switch

I can't get the sync right...but I don't drag race it enough to utilize that option, I just hit the button and go to OD....Final driving speed is 80mph @2100 rpm with 3.55s and 28" rear overall tire.

Great job on the documentation. I had documented mine but upon carrying my SD card from my camera to the computer....fell in a tub of tranny fluid at the shop I did it in....toasted

Since blowing my overdrive up I've done a fair bit of reading about this style of overdrive and there's a few things you should bear in mind. First of all a 4 speed is going to be a lot harder on the overdrive because there's no torque converter to soften the blow when the cone clutch engages. When driving around town I tend to dip the clutch just after I hit the switch because at low speed/part throttle it bangs in even harder.
With the overdrive switched out, the drive is taken up by a one way roller clutch when accelerating or cruising so it's not going to slip. In reverse or on the overrun, the one way roller clutch does nothing and drive is through the cone clutch which is held against the annulus with low fluid pressure. The cone can slip under heavy acceleration in reverse or on the overrun so engine braking should be avoided if the overdrive is switched out. When the overdrive is engaged, the cone clutch is held against the clutch band using very high fluid pressure (about 700psi) so it's not going to slip on the overrun. With that in mind I always slow the car down with the overdrive engaged and let it drop out automatically at about 15mph.
The other thing I do now is regularly change the fluid. There's a drain plug fitted as standard to my overdrive so I don't even have to drop the pan and it only takes about half an hour.

I had used Houston Drivetrain for 30 years w/no problems. The last shaft I had them make(6/10) took them three tries to get right and I had even gone so far as to print off a sheet from Denny's driveshafts with all measurements in hope of preventing just this. When it developed a vibration after 5k miles they fixed it but tried to tell me that heat from my TTI exhaust had warped it! We put a Dana in my buddies car and they screwed up on shortening his shaft also, it took two tries. They used to have some sharp folks there, but I am finding another shop.

I've updated steps 25 - 28 in up top......... Getting closer......

Nice documentation. I installed the GV unit in my E-Body last March and as you document it is pretty straight forward. I had no issues with driveshaft angles just bolting the unit in place. There was some minor clearance issuses with the tunnel as you describe, but that was it. I use it 99% in auto mode and it does not alter the way the transmission works, there is just one more shift about 45 mph. I ended up using a toggle switch in the dash to control the shifts when I decide I want to instead of the floor mounted switch supplied with the kit. I am completely satisfied with it and if I had it to over again I would. I would even have used it in my 4-spd car behind the 833 instead of the Keisler unit that's in there had I converted my auto car first. I'm sure you are going to be happy with the unit.

Troy,

I want to thank you so much for taking the time and effort to document this. I scored a nice Gear Vendors unit for $400 a while back with a T-19 adapter. I plan on installing it in my '71 R/T this summer while Levi and Ethan are home on leave from Annapolis. I am going with a simple on/off switch, as I plan on using it as a simple overdrive so I can replace my 2.76s with 3.23s.

Again, I personally appreciate what you did here. As the old saying goes, a picture is worth a thousand words.

May God bless America,
"Paladin"
Ben H. English
Ozona, Texas

Nice write up and pictures.

Did your instructions tell you to use Dextron ATF?

I was always told not to use that.

Searching the web I found this write up. Which is what I have always used.

The overdrive is shipped without transmission fluid in the unit. Remove the 13mm fill
plug on the back right side of the overdrive and add approximately 26 ounces of synthetic
manual transmission fluid (GM part #12346190 or Mopar #0487-4459). Fill to the
bottom threads of the plug. Gear Vendors specifically recommends GM# 12346190, or
Mopar #0487-4459, and it should not be substituted.

Gear Vendors previously recommended Dexron II automatic transmission fluid for its
overdrive units. It now recommends the GM synthetic manual transmission fluid for its
overdrive units due to improved shift characteristics, and less thinning at temperature
than Dexron automatic transmission fluid.

GV's website says - Fluid type - GM#1052271 petroleum based or GM#12346190 synthetic.

I have a reverse manual valve body in my 69 Bee. I leave the GV in manual and drive it like a four speed. I never put muy controller in auto. I don’t like the GV engaging automatically at 45 mph. As far as spit shifting goes it’s a waist of time and isn’t all that effective. When I want to pass I just go to second with the over drive engaged and hit the go peddle. I believe my control box is starting to go so I’m going to wire it direct through the foot switch like JDMOPAR did. I don’t really need the control box as long as I remember to disengage the GV when I stop. I called GV to ask them about using Dexron II, they said it will work with out any problems. But I did replace it with the GM gear lube. My GV installation book had a sticker on the front cover addressing the suggested change from Dexron II to the GM syntactic

Troy...I read right over the part about you using the Dexron. I originally purchased my GV for a D350 pickup, and installed it in that truck. My installation manual also had the sticker saying to use the GM petro or synthetic. I used the petro oil while it was in the truck. When I bought my 04 Dodge 2500, I pulled the GV out of my old truck and sold the truck. A few years later, I put the GV in my 71 GY3 Challenger. This time I used the synthetic GM fluid, and I'm much happier with the way it shifts. The Dexron probably wouldn't hurt yours,but I'd check with the GV techs to see.

Wow... What a difference....... I drove the Daytona this afternoon making sure all the "t's were crossed and "i's" dotted. Here are two videos of the cruise. Sorry about the quality and only being inside, but can't take outside videos when one's driving..... The unit has done everything as advertised. Engaged and disengaged right on queue. Seemed to drive smooth without any differential adjustment to any driveline angles. So far, quite pleased. I'll put a few more miles on her then check the gearlube and all wires and speedo-cable for any clearance issues...

Down the street by the house....

http://www.youtube.com/watch?v=W2OStFjZazc

Down the feeder road......

http://www.youtube.com/watch?v=9yPGInia5Lw

Glad to hear everything's working out...With a 4.10 rear you'll have the best of both worlds now !

You better get some gas! Glad it's working good for you.

You stuck a GV OD in a real '69 Daytona!!???????










YOU ARE AWESOME!!!!

The GV can be made to kick down simply by inserting a break switch in the solenoid circuit. On my own (which isn't in yet) I'll have a WOT switch on the gas pedal completing ground to a relay in the solenoid circuit.

I also noted that my driveshaft is nearly horizontal with everything from the OD output shaft, driveshaft to the Dana's input yoke perfectly aligned in a horizontal orientation relative to the floor....

Looks and sounds good Troy and thanks for taking the time to do this. Glad everything worked out for you. Makes me want to get at mine. Give us an update when you have a few hundred miles on her.
Ross

Awesome post, thank you for sharing!! Hey, where did you get that neato plastic pump thingy in photos 27 & 28?

Hemi68, I have an A518 in my GTX that was previosly fitted when purchased. Any reasons as to not using the A518? I dont know too much about their strengths but it was bought through MP back in 96 and documented in Hotrod.I hope the A518 can handle some 1/4 mile launches
see here http://www.hotrod.com/howto/43323_mopar_overdrive_transmission_swap/index.html

Im fitting a 3.91 gear next,I just hope the A518 is strong enough?
Mine also utilises a toggle switch, no biggie , just flick at speed to engage, and flick off to re-engage 3rd gear at a reasonable low speed.

cheers Dave

Hey Troy, beening following this, wonderful meeting with you with Richard, good man... i miss him a lot. damn... s#$t

Daty

Any recent updates on the car and GV?