Hey guys. I'm new
I'm a mechanic but I'll start off by saying I know jack shit about transmissions... I have a 2003 gmc Sonoma SLS 2wd... Hit some ice on the way home tonight... Rpms reved high and my trans made a weird noise... Now I do not hAve reverse. And I believe I don't have 1st gear... Anything I can check? Am I royally fucked? Expensive fix? Obviously it won't be done by me. Just wondering how screwed I am.. Thanks guys
If you have 1st and 3rd only, and will not work in 2nd ,4th or Reverse. Good chance the sun shell is fractured or splines are sheared off. Try not to run or drive the Sonoma or further damage could result.
The sun shell is a very weak point in the 4L60E transmission. This weakness was addressed by GM in high power applications by dropping the transmission line pressure when putting in to gear from park.
The best shell is the "BEAST" from SPX (
http://racetransmissions.com/store/product_info.php/cPath/203_204_206_350/products_id/692 ), they are nearly unbreakable. The Beast or the GM #24221190 revised sun shell kit has worked in most cases, however the sun shell is always going to be a concern. The revised GM sun shell rarely fails and if it does, it's most likely to strip the teeth off the sun shell.
Since you are inside the transmission, replace the Pressure regulator & reverse boost valve and sleeve: The reverse boost valve and sleeve in the pump should be replaced every 40,000 miles (65,000km) to avoid damage to the transmission. Damage can occur when wear in the boost sleeve causes insufficient line pressure in reverse. Many major repairs of the 4L60E at around 50,000 plus miles are because of the boost valve and sleeve. The valve and sleeve can be replaced easily during a routine service of the transmission for around $50. This should be considered a necessary procedure if you are transplanting one into your car. Oversized (0.490" versus the stock 0.470" or 0.420") reverse boost valves are available that provide a moderate increase in pressure, and are a good addition to any 4L60E.
Also the 3/4 Load release spring assemblies can be addressed. Remove and discard the 3/4 load release spring assemblies (5 small rectangular spring assemblies installed into the input housing, on the outside of the clutch pack). This really improves the 2-3 shift.
Long story short, if it is your sun shell that has failed, your going to have to rebuild the transmission. Good luck and keep us posted.
Molson02536
