Are My New 727 Clutches, Bands, or Fluid Burning?

Coronet said
Hi, I'm new to the forum and just posted in the Welcome section. I am worried about something I found with my car and would appreciate feedback from people with experience with 727s. I don't come from a family or friends interested in cars or mechanics, so I have been teaching myself by reading a lot (books, articles, forums) and doing the work through trial and error. I enjoy the journey, but my lack of experience and not having anyone personally to turn to for real-world experience/advice can create anxiety.

I have a 1965 Dodge Coronet hardtop that I built a 390 stroker out of the 318 LA that someone had already put in the car. The engine project went pretty smoothly last year, so this year I decided to tackle rebuilding the transmission. It's a 1965 727 with cable shift and cable park. Because the engine is putting out more torque and I wanted to get into drag racing the car, I did some basic modifications to the transmission including a 5 clutch front pack, 3.8:1 kickdown actuator lever and billet strut, and a Fairbanks "TransAction" shift kit installed to their specs for "performance street." I used Alto Red frictions and Kolene steels, and the bands are narrow flex type reds that I got through Cope Racing. I set up all the tolerances and adjustments using the factory Dodge service manual and Fairbanks shift kit instruction specifications and quadruple checked all my steps and measurements as I went along. I'm running a custom 3,500 RPM flash stall Edge Racing converter. I'm running Type F with a deep-sump pan, external oil cooler attached to the front of the radiator, and a temperature sending unit in the pan.

What I'm worried about is how the fluid smells. I have put 250 street miles on the transmission ranging from light street driving to beating on the car out on rural roads. I made two passes at the 1/4 mile strip including two very brief burnouts that I did starting and staying in 2nd gear. I shifted at 6K RPM on both those passes. The fluid in the pan usually stays at around 150*F with the engine at 180*F and has gotten no higher than 190* in heavy slow-speed traffic on warmer days when the engine gets up to 200*. The transmission shifts into all gears without issue. Automatic shifts are crisp with no signs of slipping. Under light throttle, 1-2 shift comes in at 15 MPH and 2-3 at 25 MPH. Manual shifts under WOT are crisp and firm with no delay or signs of slipping. The 3 - 2 kickdown action is firm as well. Yesterday, I pulled the speedometer cable and shifter cable to repair slow leaks coming from the o-rings, and I noticed the fluid has an odor to it that I can best describe as smelling like hot wheel brakes after descending a hill. I wouldn't call it burned smelling like burned rubber or cooking oil, but it doesn't smell like fresh ATF. I drained the fluid from the pan into a clean container, and it is still a translucent ruby-red color with no problematic debris. There was a very small amount of metal dust but nothing alarming and no flakes or chunks of metal or fibers. I don't know what burned clutches or ATF smells like, so that doesn't help. I snaked my lighted digital camera scope through the drain hole in the pan, and I see no debris on the filter fabric or walls of the pan from what I could see.

Is it normal for a 250-mile rebuilt transmission with performance frictions, steels, bands, and a shift kit that has seen a couple burnouts and passes at the 1/4 mile to have the fluid smell like this? The only problem I have had with the transmission was an issue with the Bouchillon throttle pressure cable setup that was already on the car that I reused. I had the system set up and adjusted using their instructions, and it seemed to be working fine. Last week, I gently accelerated in Drive out of my street onto a main road, and the transmission did not shift out of 2nd like it normally does. It stayed in 2nd until I got up to 40 MPH, let off the throttle, and then it shifted into 3rd. It didn't do it again until this past weekend when it did the exact same thing. I inspected the cable system and found that the hook end of the return spring that pulls the transmission lever forward had broken off to where the lever would return almost all the way forward with the throttle shut but had about 1/4" of sweep left where it needed the extra help from the spring to lock forward. Otherwise, it just stopped where it no longer had internal spring pressure to move it forward. I have no idea how many miles I have driven out of that 250 with the return spring broken, but the shifting issue only happened twice in the past 30 miles. Would the lever stopping and not returning completely forward by 1/4" fry clutches and that quickly even when the transmission was shifting from 1 -2 at 15 MPH and 2 - 3 at 25 MPH both within factory spec?

Hopefully I didn't provide too many details here, but I would rather be criticized as too thorough than vague. I appreciate the help.

So a few things, what brand Type F did you get and did you go with Type FA or Type F? reason I ask is because FA has a little nastier of an odor out of the bottle than just F. Second, if you want to know if the clutches are burning, you need to drop the pan to see how much clutch material is in the transmission pan. With 250 miles, I’d expect a very small amount especially since your transmission temperatures are very good. It doesn’t sound like you are overheating the fluid what so ever however, that doesn’t mean that something isn’t happening in the transmission to cause the fluid to smell burnt. With the issue you found regarding the return spring being broken, that could have an impact yes.

Quick example. We rebuilt my business partners transmission last year before putting in a new 572 all out race engine. Long story short, engine had to come out this year due to a parts failure but we won’t go there. We decided go through the trans because it was out. It had less than 40 runs total on it, and we had the fluid out during the season twice to do converter swaps. No signs of an issue. Then we tear into it this winter, and as soon as we drop the pan there is a ton of clutch material in the pan and fluid was clearly a distinguishing different odor. Trans never got hot at the race track what so ever. Like you are describing. We found an issue with a stator bushing backing out, causing the sealing rings on the input shaft to not seal, in turn, frying the forward gear clutches. Again, no sign of temp increase and trans was working 100% fine up until the engine part failure.

If you take the pan off and see what’s in it, and how dark the bottom looks, you will get a good idea on if something is wrong or not, or if you are being overly cautious. Sounds like you built yourself a good transmission and crossed your T’s and dotted your I’s.

Personally, I would be running DEC/MERC ATF over the type F especially on the street. We can talk about why if you’d like. Nothin wrong with type f but the Dex/Merc has more additives in it that lubricate better while F has less friction modifiers in it so the shifts are more firm.

But if it was my trans, and I smelt fluid like you’re saying, pan would be coming off to see the clutch debris in the bottom, if there is any. I feel it would be hard to see in there with the way you did it with the camera.

You were plenty detailed. That’s how things get figured out. Don’t let anyone tell you otherwise.

Something else I forgot to add, it’s possible for a servo to be stuck in turn a band would be dragging and cause fluid to get burnt.