hey guys. interesting problem making me thing i might need a shift solenoid or i have a stuck check ball or something.

occasionally, when i will have the car in reverse and shift into drive, (i never hit the gas till i know its shifted and always shift from a stop) the car will just slam into the drive gear. accelerates fine, no chopping or anything and the car drives perfect. the giant slam that rattles the dash just has me wondering what the heck is wrong with the thing. fluid is great, it was rebuilt about 30-40k ago. another thing i had it do, was the other day when i shifted from reverse to drive the car just stalled. it acted exactly like a carb'd car when cold. started it in neutral, shifted into drive with no issues and just drove on.

on one or 2 occasions it has gone into high pressure shift mode. which i find odd considering the car never, ever slips.

any info is greatly appreciated! thanks alot guys!

Are you sure its not a bad trans/engine mount? Have someone sit in the drivers seat, pop the hood, stand NEXT to the drivers side fender, not in front of the car and have your assistant go from drive, reverse, drive, reverse while watching the engine. If it slams forwards or backwards at least an inch or more of travel, then you have a bad mount. Which one, I'm not sure, but with you having a Buick, I think you have the hockey puck style front mount that fail often.

thanks alot for the info mike. seems like i remember a post on making a hockey puck mount forever ago. ill have to search that on how to make it.

Jason Definitely as Mike mentioned check the mounts/movement.
When you say it has gone into high pressure shift mode are you talking P1811 long adapt max shift codes? Did you install a shiftkit or spacers into accumulator yet?
To keep the trans free of varnish build ups, as valve body and check balls hate sticky stuff,
I would also try using a half -3/4 can of Seafoam TransTune for 1000 miles plus and then consider changing the fluids again. I think it is a good idea to do the pan drop every 30-40 k miles and do the filter then too with Dex 6.
When my trans was acting up the TransTune made a huge difference on how it shifted before I installed the Transgo shift kit. I know I had some sticky stuff going on in there.
Trans Tune | Sea Foam Sales Company

i had already planned on swapping the fluid this spring. maybe ill run a can of that thru first, thanks art. no shift kit or anything of the sort. before i had the trans rebuilt, i had the shift solenoid replaced but that didnt help the slipping at the time.

im starting to wonder if my ps pump is about to bite the dust. ive had a leaky pinion seal since i bought the car, and just keep filling every 6 months or so but tonight doing some parking lot prawling at the mall, the car seemed less than happy to turn so much at idle. could it be because i have a spinner and can turn the wheel much faster than without?

just seems to have lost its "pinky turning" feature at low speeds at idle.

thanks again guys.

I am not a big fan of magic in a bottle, but might be worth a $10 try:

Lucas Power Steering Stop Leak - Speedway Motors, America'* Oldest Speed Shop

seems worth a shot. im really dreading changing the ps pump. if the car aint cold you burn your hand on a heater hose just to check the level. sure dont look fun to actually change it.

x2 as above on Lucas PS stop leak.I dont think changing the pump would be any fun at all. I am afraid to look at manual on that one...

Re stalling when into reverse, remove the IAC and use some throttle body cleaner to get the IAC & the small inner port cleaned up & re-install it.

If I was going to drop the trans pan, I would at least get the spacers into the accumulator if not the full Transgo shift kit that I used. No more slippy or harsh shifts & I have done some real long highway drives with my PA since the shift kit install!
P1811 code is totally gone.

i havent had the code since the rebuild. had it scanned and it didnt show up. which has me stumped as to why it might slam shift like that. i had the 1811 before the rebuild also. as for the iac, its new and has the correct voltage. i was forced to buy a new one when i was soaking the old one and ruined it with tb cleaner. lol

also cleaned the seat on replacement.

Recent scan? Try the TransTune for starters....and let us know if ya got a bad um mount.