I recently had a failure with the 47RE in my tow rig. Long story short, it was locking up in 1st and reverse. Upon inspection, I found the front band was toast and the front planetary gears were destroyed. I rebuilt this transmission about 25,000 miles ago after the O.D. snap ring failed. Everything else looked fine but I did a full rebuild anyhow.

So now that it's broke, I'm wondering if I missed something or was it just bad luck? I adjusted the front band per the ATSG manual to 72 inch pounds and backed the adjuster out 1 3/4 -1 7/8 turns. I've since been told to go 2-2 1/2 turns out. Since the band is smoked and the drum is blueing I'm wondering was the band to tight or is this a result of a failing planetary gear set, vice versa? Any thoughts on what the order of operations was for the failure or what would cause this? Thanks guys!

any chance the band apply piston cracked? I don't think your adjustment was far enough off to cause any damage. Planet letting go to that degree is odd, but I've seen it. Hopefully you can find a good core to get parts from.

Just to give you some ideas, some of these have a check ball in the transmission line, it is supposed to help with converter drain back when the vehicle sits, so air does not get into the converter. This check ball can melt, or get stopped up. Fluid flow is out of the converter through the trans cooler, and then into the lube circuits of the OD section. Also when you did the overhaul how did you clean the cooler? A flushing machine is almost a must have now in a shop if you do transmissions. If you had a lube flow problem, the trans does not shift funny, it just gets hot from lack of lube and destroys itself. Many of these transmission failures also come from the lining material of the lockup plate in the converter coming off and clogging the above mentioned cooler and starving the lube circuit. When I did my truck I did the dual disc towing converter and knock on wood, 125,00 miles towing a 12,000 lb trailer and it has nice pretty red fluid, and going strong. Root cause of my failure was the converter coming apart. I also removed the melted check ball, and installed a transgo shift kit, which also helps with the drain back issue.

Lube failure.

Bad luck - but not a lube failure. Lube failure would have spalled the pinion shafts, turned the thrust washer blue, along with blueing of the pinion gears. These parts do not show any of that. If there are no other failed planetaries in the main case this further supports just a hard part failure.

Lack of lube affects overdrive transmissions differently than a regular three speed. If your overdrive is fine than chalk this up to just bad luck. I'm sure you will spend a lot of time cleaning it up - that thrash gets everywhere.

And jwb123 is spot on about past issues with lack of lube.

I think of lube failure and brings up visions of intermediate shafts welded to the OD support on an RE. If I had a failure of that magnitude, the coolers would get replaced. I'm also not a "fan" of that checkball. Removed it on my 01.

I've never seen a planet break like that. My bet is something wedged between one on the teeth. What was that object? If I had to guess one of the planets had a flaw and either cracked in half or broke a tooth off. Totally different scenario. A few years ago Dizuster had a NV4500 that broke the output shaft in half. You could clearly see it had been cracked a good way though before breaking all the way. So parts do just flat fail. I've seen failures on the transmissions from lack of lube.The ones I've seen do not look like this.
Doug

The failure is due to the thrust washer or wedding ring wearing thin, breaking then getting in the mesh. Common failure on high mileage planets - usually the front because it sees the most use under load. And most always on truck applications. The thrust washer and wedding ring (one of each) is used on each side of the pinion gears. You can't normally see the wedding ring but it keeps the needles away from the thrust washer you. In the bottom image - you will see one in the lower portion if the picture still on the pinion shaft. Plus there is one laying on the table in the lower left of the picture with broken parts spread out.

One of either part - when they fail causes the catastrophic failure to start. Usually the thrust washer.

After 20k miles - I doubt you left something loose inside to get in the mesh.

So after hitting several dead ends attempting to find a core, I dropped off the broken parts at my local transmission parts place and set him free to round up replacements. He's getting me the hard parts, clutches, O-rings, nylons, thrust washers etc. Basically everything I need to get it back together with a fresh rebuild. Total damage was around $500.

He also recommended getting the check valve out of the cooler line and after discussing the affects of doing so, I decided to modify the valve body for fluid flow in the Park position. The wife and kids sit in the truck sometimes when I run errands depending if one of the kids are asleep and I figured it was a win-win modification when considering heat build up and drain back potential once the check valve is removed.

I did inspect the front band apply piston for cracks but did not see any. I'm going to dig a little deeper though because I would really like to know what cooked that front band and clutch pack so bad. He said the pressure plate had warped from the heat as well so there's gotta be something there that I'm missing. Could be a faulty check valve, I'll know soon enough.

ANyhow, I'll look a bit harder at everything this weekend and report back. If you guys have any other thoughts, please let me know. I appreciate the input! - Trent

I still have the original trans for my 01 in boxes.... that stuff isn't laying around like it used to for sure.

I bought a valve body kit and torque converter from Dave Goerend. Used a stock overhaul kit (Borg/Warner) and replaced all thrust washers and bearings. Knock on wood it's been doing a fabulous job for over 13 years and 130K miles.

"IF" I had a failure of that magnitude, I'd be replacing the coolers.

MadMopars - the two failures are independent of each other. If just the front clutch and band is wounded then likely you have a leak somewhere in the front end. Look over the reactionshaft support seals and grooves - to the front drum - are either worn badly or the seal grooves are worn and/or you have a leak on the front serve release side.

As for cooler replacements you can never go wrong by replacing them but this failure doesn't require that - the 50 micron sump filter keeps stuff larger than that out of the coolers. A converter failure - goes STRAIGHT to the cooler. Of course you want to flush the cooler in the direction that's in reverse to its normal flow for as long as you can - to get the dirty fluid out. You might want to install an inline filter in the return line - but you should always check cooler flow before putting the unit in service.

I had my A&A planets split like that along with the clutch,bands,Very interesting.