Alright, so lets start at the beginning.
In mid-late August I installed a BM 70268 Trans cooler on my 4R. I installed it using the Timmy the Toolman video, but I removed my rad and only ran the zip-ties through the condenser, not both condenser and rad. I used the line and screw clamps included in the BM packaging, as well as some 3/8 inch bulk line from Advance.
After install, I checked for leaks, nothing, looks and drives ok. The only thing was that it seemed hesitant to accelerate when the car wasn't warm.
About a week later I drove about 300 miles round trip on the highway to Richmond VA, with a lot of mountain highway driving. At some point, my line came off the lower nipple of the cooler and began leaking fluid. By the time I arrived home, the back of the car was soaked in fluid, the car would rev and take a long time (1-2 seconds) to actually engage the driveline when accelerating from a stop, and the next morning I had a red puddle under my car. I was using my phone to monitor trans temp on the drive and even when it was low on fluid it never broke 200 degrees. I go to Advance and I buy 8 Q of
Castrol Transmax Import Merc/Dex red ATF. I had to put about 7-8 Quarts in. get in and drive vehicle, no CEL, no shift issues, no high rev at idle, no high trans temperatures. All is well except the BM cooler appears to be leaking. Order a new one from Amazon and get the faulty one replaced. When I swapped for the new one, I really tighten down the screw clamps, and rerun the lines so now the trans doesn't have to pump the fluid upwards as much except for when it is inside the cooler. Drive car, all is well.
I'm surprised it moved at all with that much fluid missing
Fast forward to October, I'm driving up a slight incline, 55-60 mph in O/D and I feel the trans slip, just once, and then I take it out of O/D and it does fine. It has done it a few times since again, uphill, in O/D, around 60 mph. 65-70 mph, I think the engine is revving high enough to take some of the strain off of the O/D gear to prevent it from slipping because it has never slipped at that speed. The other extremely weird thing is that the acceleration lag is back. I put my foot down and the engine does not rev up as it should normally. It is almost feels like the traction control is preventing me from accelerating. It will eventually let me accelerate after a second or two of no response from the accelerator. One thing to note is that while this sluggishness is correlated with the new cooler, I also tackled upper and lower ball joints up front when I put the cooler in. I'm wondering if the speed sensor isn't getting a good read on the ABS rotor after reinstall? I'm not sure. Also I still have a slight drip of trans fluid coming from the condenser where the cooler is even after tightening down the screw claps as tight as they would go.
That slipping feeling at that speed indicates a torque converter failure to me. If it was a traction control or abs issue then it would accelerate fine at first (1/2 second to second) and then become sluggish. Upper and lower ball joints wouldn't affect acceleration. The dripping is more than likely from residual transmission fluid in the condenser and radiator from when it leaked. Only way you're going to get rid of that entirely is removing the radiator and spraying both sides of the condenser and radiator down with brake clean or other solvent of your choice. You could try spraying the front of the condenser with simple green concentrate while it's running, let it sit for a couple hours, and then spray condenser/radiator down with a garden hose.
SO now what to do. I took it to a trans shop and they told me a rebuilt trans swap from one of their suppliers is 2900. Another shop quoted me 2500 for a rebuild of my current trans (which seems astronomically high for a rebuild). I asked the first shop if a simple drain and refill would help and they said that would actually make things worse because it could compromise some of the current friction between the clutch plates in the transmission. However, some friends have told me do a drain/flush, trans filter replacement, and put a bottle of this
Trans Fix in there with some new Valvoline synthetic ATF. The way I see it the car still runs and drives and if I try a few cheap fixes before putting a new transmission in it, I'm not making it any worse. What should I do? Old fluid and add Trans Fix? New fluid and filter no Trans fix? I don't know how transmissions work in the slightest so if you told me to dump old bacon grease in there I would probably believe you.
I would replace the filter and add new fluid. Do several drain and fills over the course of a few drives. If it's still giving you issues then drain some fluid out and add the trans fix. I'll never use a transmission "fix it" additive, but at that point you won't have anything to lose by doing it.
Thanks for any advice you may have.
