DrX

iTrader: (7)

A couple of times now I have had a loud bang when shifting from drive to reverse as if something was binding. It happened again today and now the motor wants to stall when I shift from D to R after driving. Any ideas what's going on?

Vince B

iTrader: (1)

Are you using a multi disc converter? With you saying that it wants to die it seems like maybe for some reason the clutch might be dragging. It really shouldn't do this because the 4l80e is using second gear feed oil for the tcc but anything is possible. I would get in touch with your transmission guy to see what his thoughts are and maybe contact the converter manufacture to see what they have to say. HTH Vince

DrX

iTrader: (7)

Thanks Vince. I have a single disc converter this time 'round. No lockup at WOT. I did find today that the converter bolts were or had been rubbing on the dust cover - not sure if this was old or new wear on the cover. Modified the cover, but it still stalls if after driving I stop and put it in reverse. It doesn't do this if I start it up and put it in reverse to back out of the garage after it has been sitting.

budhayes3

iTrader: (19)

I remember an old ASE test question about stalling when put in reverse, and the correct answer was a clogged transmission cooler...although I'd think that if the cooler were clogged there would be bigger problems causing it to clog...and this doesn't account for the "bang" either...

Gilbert@Ace Racing

I'm curious to know how old this build is and what the fluid condition is... The first time you experienced it had you been pulling a trailer, anything different in the way you've been driving it? Any changes to the tune or your combination lately?

g

DrX

iTrader: (7)

Cooler flow is easy enough to check.

Trans probably has around 1000 miles on it. Fluid was changed about 500 miles ago when I re-installed the motor after a rebuild. It looked pretty good at that time.

No towing, but no kindness to the trans either behind this motor.

Trans pressure gauge is showing over 200 psi at WOT.

The driveline bang first happened after I put the truck back together. It has only happened about 3 times - truck may not have been on a level surface at those times, or the wheels may have been turned. The first time I was backing up a slight slope into a parking spot.

The stalling just started a few days ago. When it happens, it does feel as if shifting into reverse puts a large load on the engine.

The tune has been constantly changing, but I haven't touched the trans tables recently. Currently fighting what sounds like a misfire when in boost - but I don't think it is in the tune. Last time I was in the trans tables was to adjust shift pressures when I scaled the tune 50%. Haven't touched the "Standing Shift" tables.

Chavette

iTrader: (6)

I would go back and look over the converter some more since it has evidence of problem...run a marker on the bolts/cover and see if it wears back off.

On another note, it reminds me of a broken cross member where the engine is picking up the tail which might result in stalling and banging. All the bolts back in the mounts, cross-member, u-joints, etc. and tight? I would take take a tranny jack or bottle with wood and put some gentle lift pressure on the tranny pan then the engine to see if everything is secure (not loose or broken).

Also is it still a 4WD autotrac (noted Z71)?

Atomic

iTrader: (42)

My trans does the same thing when shifting into reverse; the engine acts like its under a big load and nearly stalls. It has stalled on occasion when im backing up and turning. Stock rebuilt trans and pi triple disc converter. I am changing the converter to a stock one today or tomorrow so im wondering if that will make any difference.

budhayes3

iTrader: (19)

May be way off here, but easy enough to check...if you're still running a MAF, and the intake tube is loose, it may move and leak when the engine torques when put in R. This could go along with what Chavette mentioned about loose/broken mounts.

DrX

iTrader: (7)

I cut off the part of the dust cover that extends up around the starter yesterday, so it won't be rubbing anymore. Didn't help the stall issue.

No MAF.

Still 4WD but I'm always in 2WD.

Just dropped the fuel tank to check things out as my surge tank does not seem to be venting at all now. Pulled the hose to the big pump off the bottom of the surge and fuel only dribbled out even though the surge tank was full. I'll check out the trans mount, etc. while I'm under there.