I have a "goodwill" agreement in place with Monster for an AOD I installed in my 73 Mach 1, so I can't share some of the details of my experience. But, I can say that in the end I was satisfied with the transmission, which is not a derogatory statement. I wouldn’t dissuade anyone from getting a Monster, but be sure to ask for their upgraded firm shift version with an AOD. I personally will not be able to order from them again as of the agreement that says, "No legal actions will be made against Monster Transmission & Performance." In the event I were to order another AOD, or more likely 4R75W, I would do so from a vendor where my legal remedies were not available in the event of an issue that adversely impacts the performance of the item purchased. Otherwise, I would likely order from them again.
The Monster warranty is not unusual. The issue when buying a rebuilt transmission is that has to be shipped, & if there is any kind of problem the warranty does not cover the labor cost of removing the transmission, shipping the tranny back to the rebuilder, much less shipping the corrected tranny back to the, plus the sddiyionsl installation labor expense - which represents a lot of money to be spent to get warranty work done -
unless the builder authorizes work to be somewhere local to the consumer. So, in essence any value of a warranty for distant buyers is economically nullified unless a consumer is able to work out an arrangement that allows for reimbursement for effecting needed corrections to a rebuilt transmission that had an obvious error. But, in order to do that, you may just need to be able to convince the rebuilder that if they do not cooperate in a reasonable way they will face the prospect of being dragged into court with a case they will clearly lose. Absent that it is not likely you will get a rebuilder to assist with expenses incurred with a transmission problem. In having said that I am not saying this was or was not the situation I ended up facing. It is just a definite consideration when it comes to warranties made on large, very heavy items.
In my case our 73 Mach 1 not factory original. It began as a base 302 2v Mch 1 with a C4, 70 series radial tires, & an AM radio. It was ordered with fuel economy in mind, as the rear axle ratio was a steep 2.78:1. The prior owner replaced the rear axle gear set with 3.5:1 TractionLok gears. The original 302 also ended up with a distributor shaft driven gear getting into a fight with the camshaft gear, & the engine lost. He moved to a 351W engine as he wanted a 351 that would perform at lower RPM levels, as opposed to having to wind it up to high RPMs as with the 351C. So he got an engine from a 94 F-150, and installed heads from a 69 351W 4v. The engine was built moderately, putting out 360 HP on a dyno.
Other than its 750 CFM Holley tending to blow out its Power Valve every time it would backfire on its initial startup every Spring, the engine ran well. (Hang in there, I am going to tie all this into a consideration for those considering a move to an AOD, I promise). I ended up replacing the Holley with a new 750 CFM vacuum secondary carb, which included a Power Valve Protection feature that prevents Power Valve blowouts.
I enjoyed the performance, but the 3.5:1 rear axle gear ratio meant I was turning nearly 3,000 RPM at highway speeds, which after a while got on my nerves. So, I decided to get an AOD when its original C4 finally gave up the ghost after a few too many Wide Open Throttle 1st - 2nd gear rubber barking upshifts. I now cruise at 60 MPH while running almost 2,000 RPM in OverDrive.
I decided on swapping in an AOD, as opposed to rebuilding the C4 and installing a Gear Vendors OverDrive unit. It was a matter of financial impact, where going the Gear Vendor's route would have nearly double the cost of getting and swapping in an AOD. And, I opted to do the AOD vs AODE or 4R70/5W tranny because I did not want to deal with getting an electronic controller to handle the shifting or manage its shifting behavior.
For anyone still reading this little novel-ette, here comes some good information for anyone considering an AOD swap... There are two things I would want to consider were I to ever do another AOD swap...
First, our AOD came from an F-2150 that apparently have a 4x4 transfer case, as its output shaft was the shorter one as compared to the AOD's regular tailshaft length. It turned out the AOD's distance from the end of the tailshaft to the rear axle pinion yoke was inly 1/4" longer than the C4's length. And in looking at the wear pattern of the transmission rear oil seal on the driveshaft's front yoke, I have about 3/8" of travel not yet reached. So, I was able to install our AOD without having to cut the driveshaft shorter or and rebalance the driveshaft. One less complicating factor to deal with. I have a friend whose driveshaft alteration ended up being 1 centimeter too short with its shortening. Bummer...
The 2nd thing I learned is adjusting the Throttle Valve pressure is not really hard, but it is tedious. Getting the brass adapter tube screwed into the passenger side oil pressure port for the needed oil pressure gauge is a bit of a PITA. How bad is it, with the tight fit? Well, I did a video of three different times I decided to adjust the Throttle Valve pressure, and one of them shows pretty clearly what was involved. To see that part of the video go to time marker from the beginning of the following YouTube video:
https://www.youtube.com/watch?v=KYIAqqYUKNo
Anyway, I ended up having to connect the oil pressure gauge to the test pressure port of the AOD three times, as I kept trying to alter the Upshift road speed (and the firmness) of the upshifts. Each time it was a tedious ordeal. Had I gotten an AODE, or even better a R70/5W, I would have gotten a few benefits. First, the later models of the 4R70/5W transmissions are reportedly very strong, more durable than the early AODs. Second, I could have adjusted the Throttle Valve and other behavior characteristics electronically with an aftermarket electronic control unit. As happy as I am with the AOD, and its impact on the drivability and comfort, I do believe I would have stepped to the 4R70/4W tranny and also purchase the most adaptable controller on the market.
Finally, just another thing to ponder, I was able to retain the original auto tranny shifter and use it with the AOD. The shifter detent marking do not match the AOD tranny mode perfectly, but it works. Here is the difference
Shifter
Mode C4/6 AOD
P P P
R R R
N N N
D S OD
2 2 D (1:1)
1 1 Not on AOD Shifters*
*Although the AOD shifters do not show a further detent position further out than "D" I have found that there is something called the "AOD Shuffle." I have read enough reports of it being hard on the transmission to not play with it much, but I find its behavior interesting. When I am in the shifter's "D" position I have gone as far as the AOD shift detent allegedly goes. But, surprise, surprise, were I to shift into the shifter's first (1) gear detent position the AOD will actually let me move there. And, if I am traveling at an "appropriate" speed it will even drop the AOD into 2nd gear - and if I am going even slower it will drop it into 1st gear (depending on what the AOD governor is doing). If I were to accelerate at Wide Open Throttle off a standing start, I can accomplish the 1-2 upshift manual if I do not want to just leave the shifter in OD and let the tranny handle it.
Here comes the shuffle... I accelerate in 1st gear with the shifter in the 1st gear position. When I have hit the RPM I want to shift into 2nd gear I move the shifter from 1 to 2 (which is "D", 1:1 direct drive in the AOD, or 3rd gear), and immediately shift back to the "1" position on the shifter. That "shuffle" from 1 to 2 and back to 1 will force the AOD to shift into 2nd gear, as the governor will not allow it to go back into 1st gear at that road speed. Then, when I have hit my target engine RPM in 2nd gear I shift into shifter position "2" - which is "D" for the AOD, third gear which is the 1:1 direct drive ratio. If I am on a track, and hit my target engine RPM in 3rd gear I then shift into "D" position, which is the OD position, and once I have run it up as fast as I like (on a track), I can back off the throttle and return to a less exciting speed.
The AOD Shuffle may seem strange, but it is logical. And finding I can shift the oem shifter into "1" position was an unexpected treat, much less finding I could indeed for a 1-2 upshift manually even though the shifter does not provide for a physical position for 1st gear. An aside, I have been looking for an AOD version of the shift indicator dial to install in my Mach 1's oem shifter, just to be able have a shifter indicator that shows the forward gear I have selected without me having to think about it. I have yet to find a vendor who supplies that kind of dial, but it sure seems to be something a 3d printer ought to be able to handle! Hmmm, a project for later this year maybe?
