drman929

iTrader: (4)

So i just rebuilt my 4l60e, and I have movement in R, 1, and 2 but nothing when I put the shifter in 3 or 4. After doing some reading, it seems like it could be the forward sprag..but I put a new double-caged sprag in it and double checked the direction that it holds as per my atsg manual. Tranny makes no noises and the other gears engage like they should. Is there anything else it might be or do I just need to tear it back apart?

Predator T/A

iTrader: (7)

in 2nd you should have a 2nd gear start the oveerun clutches are holding also in 3rd range so it should still move even if the sprag was backwards...you may want to loook at the low roller clutch it is the only that is holding in all the ranges except with manual low which wil lbring on the low reverse clutches and give 1st gear in manual range. it goes off in 2nd range but you would have 2nd gear start so it wouldnt matter and in third range the low reverse would also be off. I think you have a problem in the low roller area.

drman929

iTrader: (4)

Thanks for the input. Looks like I'll be tearing it down again! It had 39,000 miles on it...everything looked fine inside except for the 3-4 clutches..but one time under a hard 1-2 shift it felt like a sprag let loose, but it still drove fine unless I really got on it. Maybe I replaced the wrong sprag...lol

Predator T/A

iTrader: (7)

yeah the low roller clutch is in the bottom of the trans under the sunshell it goes inside the support. they are bad about breaking or rolling the rollers and kicking springs out. you should have forward motion in D3 also if the input sprag was broken because the ovverun clutches are coming on in d3 also but the low reverse clutches are not only thing that ould be applied would be the low roller but appears to be bad in m2 it will give a 2nd gear start anyway so it wouldnt be needed anyway and in M1 the low reverse clutches come on and do the job that the low roller clutch should be doing which is holding the rear planet carrier.

Vince B

iTrader: (1)

The OR clutch on a factory valve body only comes on in the D3 range when the trans shifts to 3rd gear. So you will not have movement in the D3 range from a stop in first gear. Just saying. Sounds like the sprag is in backwards. Vince

Predator T/A

iTrader: (7)

hmm guess my ATSG manual must be misprinted lol so yeah check the input sprag if you hold the small hub towrds you you should be able to turn the small hub clockwise and lock counter clockwise you could also have a bad sprag I have seen new ones that will hold on the hand test but not hold against the torque of the motor also you could have worn races also. if it were me I would order a new sprag assembly befoire I put it back together.

Predator T/A

iTrader: (7)

lol now i am really confused ATSG says its on in all manual ranges ....but hydro diagrams from GM SI says on in M1 off in M2 and on in M3 lol....as a side note if its in backwards try going to 4th lol with your seatbelt on lol. it has to ovverun in 4th it will either lockup the wheels for a moment and then smoke up the ovveruns
lol GM si on the application chart says the same thing vince said lol you learn something new each day. yeah most likley the sprag is in backwards

Vince B

iTrader: (1)

I cant remember for sure but IIRC it will blow the band out of the trans. Been a while since I have seen this mistake made on the dyno but either way its going to hurt something. I would not try this on the road but it could be interesting on jack stands!

BTW when I say blow I mean smoke not launch!

Predator T/A

iTrader: (7)

LOL I was actually just kidding lol ont do it iwas hoping that the OP would know that I was being destructive....I put a th400 intermediate sprag in backwards one time that was a fun test drive when it hit third at 55 bout the time i said **** no second and then there was one of those WTF moments

dieseltech71

I have done a bunch with no movment but 1-2. I find the forward sprag as well as the overrun clutches are failed. So if the overrun clutches fail along with the sprag, then all you will have is 1-2

Predator T/A

iTrader: (7)

with no ovverun and no sprag you wouldnt have any movement as the front sun gear wwill not be able to turn remmeber the outer hub is splined to the forward clutches and the inner hub is splined to the ovverun which is also linked mechanically to the sun gear..with none of these turning you would have a N transmision

drman929

iTrader: (4)

Well thanks for the help. The sprag was backwards...embarassing....lol..I'm gonna put a few more goodies in it and put it back together in a few days. We'll see how it goes now!