I recenlty had a problem with my 350 THD in my Skylark 455. It started with a trip to the performance shop. I started the car (cold) summer weather not winter. I put the car in reverse...No motion.. I reved the engine a little...still no motion I tried all gears nothing. I checked the trans fluid with the car at idle. Everything looks full and clean???? I then shut the car off... Then restarted it and presto it moves fine in every gear like nothing was wrong???????? I then proceeded to the local performance shop to have addtional work (other than the tranny done).... They at one point noticed the same issue. With their suggestion I ok'd dropping the trans pan...??? As I expected the shop mention the pan had a lot of debris. It seams no matter how new or old they always find debris. They mentioned the trans fluidn was burned????? I have cooked other transmissions and know this fluid was in great shape not burned. It may have had debris but not burned. I ok'd a full trans rebuild with all of the needed goodies to support a 600hp real wheel engine set-up. They did a great job... Drives great. It appears the problem is still there. They hooked an external pressure gage to monitor the issue. They found that the pressure drops to zero when this occurs..They find the pump has great pressure in excess of 170 or 180 psi. and was in great shape as discovered during the rebuild. This only occurs when cold startup...After its its fine... The shop change the boost valve with a replacement from sonnex..No change... Any thoughts will be appreciated... Thanks in advance Ray PS. Torque converter was install new about 6 months ago and does have a 3000stall... :laugh: Update, trans is fixed....problem was a seal in the forward cluth pack..... Thanks everyone....
Raymond, welcome aboard. Unfortunately I'm no TH350 expert, but from the symptoms you describe it sounds like there may be a valve in the valve body hanging up intermittently, but it's a guess from what you've said. It might be binding just enough that it moves freely only when warmed up. Hopefully you'll get some better feedback really soon! Devon
I get a similar situation with my TH 400. Although I do have reverse when it happens, just no forward speeds. I just sit there and blip the throttle for a minute or so, then it engages...
