pokerfreak07

I have a mildly built 4l60 w/2800 stall (5k miles old) and i lost every gear including reverse. I was on the freeway goin about 55 and punched it... it grabbed and hit the rev limiter, it immediatly lost every gear including reverse without any noise, feeling, leaking, cel, etc. Any ideas or words of advice before i have to have it totally taken apart? I only have 390whp so this mild trans shouldnt be gone after less than 5k miles.... Thanks for the help!

pokerfreak07

Its in an 04 gto.

oldgoat69

Not trying to hijack your post, but I have a similar issue. My set up is DBW, LQ (magnacharged) with 4L60E. If I roll into the power everything works like is should, trans downshifts and all is well. If I mat the throttle the trans seems to completely declutch and the engine bounces off the rev limiter. Back off throttle and it will recover. Any ideas?

mrvedit

I'm no trans expert, but it sounds like your forward sprag is slipping, which I understand is not uncommon. Borg Warner makes a stronger unit, but this requires a fair amount of disassembly.

As to completely losing forward and reverse, I posted this on another thread (and no one corrected me):

It could be the torque converter, torque converter to flexplate bolts, input shaft or output shaft.

Do you have [P]ark? If yes, then your output shaft has to be OK.

Or, it could be a failure of the oil pump or even something as silly as the wrong oil filter (e.g. falling into a deep pan.)

pokerfreak07

Yes i have park... Should have said that before.

mrvedit

I wish a more experienced person would chime in here, but here is what I would do:

First, check that the three flexplate to torque converter bolts are in. You only need to drop the starter motor to have access to those bolts. This examination should also confirm that nothing crazy happened to your flexplate.

( I have heard of situations where there was too much clearance between an aftermarket torque converter and flexplate. Then as they are tighten down without spacers (that should have been installed), the torque converter was barely seated in the oil pump and finally disengaged. It is the torque converter that turns the pump. All this is very rare, so lets skip it.)

If the bolts are secure, then it has to be the torque converter, oil pump, input shaft or input drum. I suspect at this point you would take it to a trans shop, but let me continue...

While a trans shop could test for line pressure to determine if the oil pump is working, that is probably mute as the trans will have to be removed anyway. I have no experience with torque converter failure, so a trans shop or someone else will have to advise you on that.

My guess is that your input shaft is OK, but its spline may have cracked the input drum where they fit together. This will require at least a partial rebuild. Sonnax makes a $45 kit to reinforce the input drum in this area; that could be installed onto the new drum:
http://www.sonnax.com/system/instruc...733-01K-IN.pdf

For more strength, Sonnax sells a $320 kit that includes the stronger 4L65E input shaft and drum modified to fit into older transmissions:

http://www.sonnax.com/product-lines/...ion/parts/3168

Again, I'm no trans expert, so please seek other opinions too.

bwkmaro

what did you have done to the tranny to have it mildly built is my question

somedude

years ago this was a issue on taurus SHO automatics. The filter would fall to the bottom of the pan which raises the oil pickup several inches and causes the symptoms described.