48re won't move in drive.

[Branden]

As the title states, I have a 48RE behind a 5.9ctd, 04 (late 03 build) Initially started out fine. Drove to store and back after big swap (I swapped the engine and trans into a different truck) decided to test drive further, stop at store, back up fine, put in drive and at best it felt like someone nudging the tailgate. Messed with it for a minute, put it in 1st and was able to manually shift through the gears and get home. Messing with it it got progressively worse. Pulled the pan and had some very fine aluminum in the pan. Called monsster trans and talked to Earl, described everything to him and he said that I most likely ballooned the TC.

So I replaced the TC and installed a transgo SK while I was at it. Checked the clutches while I had it out and they looked like new. Adjusted bands while I was in there as well per spec.

Got everything put back together and truck still won't move in drive but can shift manually. Seems like some slipping going on as well. It also won't kickdown, well it will, bit it just revs until I let it shift back up.

I'm at a loss and in desperate need of help to figure this out.

 

[04.5inline6]

This to me sounds like a classic case of the one way bearing, sprag clutch, or “over running clutch” in the back of the main transmission case spinning. in performance transmissions, they need to be drilled and tapped so that they can’t spin in the case. The picture below shows where to put the screws. The overrunning clutch is what holds the reverse drum, in the back of trans case. once the overdrive is removed, then the overdrive piston & housing taken off (there’s 6 bolts behind the overdrive piston) then you will find great back of the case. this is where you need to measure out the distance in the picture and drill and tap 4-6 screws (I prefer the 3/8 allen headed ones). unfortunately, this does mean the removal of the transmission is recommended, and possibly the transmission case be replaced, depending on the severity. I’m 16 years old and have built four 48re transmssion top to bottom with well over 25,000 miles on all of them currently and at over 500 horsepower each. While you have the transmssion out I would also look into getting a different torque converter or at least having a trans shop cut it open and freshen it up. Goerend, suncoast, DPC, and even Monster transmissions can all help you with that. If you have any other questions, just ask! PM me if you would like a phone number for any shops listed or myself. I can help you out with your transmssion issue one way or another.
-Brock

 

[Dan_69GTX]

Did you do any pressure checks to see if pressure is applied appropriately?

I agree that if the trans works when manually shifted in to 1st, it is most likely an overunning clutch in the back of the case. There is typically no warning that this will happen, it just does.

Bummer you replaced the TC for nothing. I really doubt there was a problem with it since the trans works, just not in drive. If it didn't work at ALL, then I'd suggest the TC as a POSSIBLE culprit.

Unfortunately now, your new TC will have small aluminun grit in it, and should be replaced again, or cut, cleaned and welded back together. Due to the "grit", especially if the overunning clutch did spin in the housing, you should clean out the entire trans.

Sorry for the bad news.

 

[Branden]

Sorry for not replying, been busy and frustrated. Unfortunately the sprag was the problem as you both suggested. Case, sprag, reverse drum and a couple of thrust washers are all thrashed case will be here tomorrow.

 

[Dan_69GTX]

Thanks for being kind and letting us know what happened/the results are. All to often, that doesn't happen.

 

[Branden]

Thanks for being kind and letting us know what happened/the results are. All to often, that doesn't happen.

Your experience is much appreciated, this little adventure has however sparked more questions. Such as why there isn't a fix for the lip thing similar to a bolt in sprag (I don't even know what to call the lip in the case that broke off, where the race presses in). The case I have is already tapped for a bolt in sprag, but from what's left of the one in there it doesn't look like one was installed. I have a pic but it's file size is to big.

 

[04.5inline6]

Usually the splines on the case are stripped out by the pressed in sprag clutch housing thingy. Not sure what it is called either, but in most cases the splines are just stripped out, but in your case the whole thing actually broke off? or did I read that wrong.... Anyway, thanks for the update, pm me if you have any questions upon reassembly and/or need parts or literally anything. Thanks again!

 

[cerberusiam]

There ar ebolt in sprags for the 47\48RE that fix the stripped spline problem and keep it form happening. Doesen't make the sprag part any string as they still use the plastic retainer but it addresses spinning it.