From what I’ve read, the 4R70W is somewhat smaller and can be a fairly robust trans as well, but glad you were able to make the 6R80 work. There is a company (Performance Automatic?) that offers the 4R70 with a different bellhousing grafted on so an adapter plate (and resulting thickness impacts) isn’t needed.
It isn’t something I would tackle for a while anyways…interested in seeing what others are doing though.
Hi,
At this point, how are you feeling about the 6R80 swap? Still loving it or any complaints?
I definitely need to do some type of OD in my 69 with FE. The 4 options I was looking at are Gear Vendors, AOD, 4R70w, or 6R80. The last two require the use of an adaptor plate and a TCM it seems like the 6 speed might be the best case scenario for range of drivability. I’ve done plenty of AOD swaps behind 351 and ran one behind a mild 460. AOD with it’s direct shaft might be a bit clunky with the size cam I have. While a one-piece input shaft is available, the use of it deletes the direct mechanical connection leaving only the fluid connection in the convertor. The 4R70 is probably the same intensity of installation as an AOD, but now requires a TCM. So, why not use a 6 speed-----if it shifts good. The gear vendors is an option, but the OD gain is only 22% versus 33% for AOD, 30% for 4R70 and 31% for 6R80. Plus, without some form of TCC lock-up like the OD trans have, the decreased leverage of any OD ratio will cause the convertor to stall higher reducing potential rpm drop. GV is probably out unless I find one really cheap.
The thickness of the adaptor plate you had used is not thrilling. I have some ideas on making a thin plate. We’ll cross this bridge when we come to it.
I am really liking my 6R80 swap. No regrets at all thankfully. It’s a great setup to romp around with.
You’d mentioned about getting a TCM with optional programing to select starting in 2nd due to the deep 1st ratio. Do you use that function? Also, what rear gear ratio are you running?
I start out in 1st gear like any normal automatic. Currently I have a 3.89:1 on 26" tall tires. The eventual plan is to use 28" tall tires. Once the engine gets built I may experiment with 2nd launches etc… No need at the moment. Also I am not locking up the torque converter at cruise. Engine runs too rough for that.
Rough running due to cam causing “trailer hitching” effect is a good reason not to use AOD…but I would still want lock-up for efficiency. How much cam do you have and what rpm are you cruising at?
I’ve been pondering about the above trans I’ve mentioned…so far I am leaning towards the 6R80 as it has the most to offer. Perhaps it’s time to start accumulating pieces for this swap.
I have to say, reading your thread has been influential in swaying me towards the 6 speed…thanks for posting your journey with this swap.
My rough engine is the result of a dead cylinder to two. Probably the valve seats are shot. Cylinder 6&2 are 120&130psi whereas 8&5 are at 158&168psi. It an ‘RV’ can from what I was told.
Part of the reason I have made it this long is because the electronic trans doesn’t use any engine vacuum. Hoping to get a couple more seasons so that my new motor is ready.
Hi,
The 6R80 has no provision for speedometer cable, what do you do for speedometer? Is there an eletronic conversion to use signal from the TCM?
Yes. I used the Dakota Digital ECD-200BT. It works well and has an app for your phone that allows for fine tuning of the MPH.
This is a great writeup on a 6R80 swap, the best one I could find!
May I ask a question. Could you have made the stock Cougar floor shifter work with the 6R80 trans?
Thanks for the comments. I don’t think I could have made the stock shifter work. The stock shifter sits down in the transmission tunnel and is really close to the output shaft of the transmission. Have a look at my first video where I talk about that some. retrofitting the stock shifter handle to the base of a Lokar or OEM FORD 6R80 shifter may be a better approach if you had to have that look.