: Occasional tranny slippage: Shift solenoid???



JSMeloche
04-20-05, 09:35 AM
I own a 95 STS, just past 100k a couple of weeks ago. Now the tranny sometimes slips from 2nd to 3rd gear under light/medium-light throttle. Ive checked the code and there is nothing... Could this be the A&B solenoid going bad??? or is it something else in the transmission malfunctioning?.

Here are the symptoms, usualy when it shift from 2nd to 3rd a around 2800rpm, the rpm will go up to 3000 during the shift and slip there for 1 second then "fall" into 3rd, not a smooth shift. I have not been able to repeat the symptoms every time.

Last summer, the morning after racing the car at the track i had a A&B Solenoid code in the computer, i reseted and everything was fine.

As i understand the N* PCM is pretty robust and should warn me of possible damage and "lock" the transmission in 2nd if there is a problem with the solenoid. But the tranny is slipping and its not telling me anything... can i damage the transmission? should i just go ahead and replace the solenoid before i toast something in the transmission?? (clutch, gear?)

zonie77
04-20-05, 12:24 PM
If the solenoid is cracked it may just stick occassionally, before it breaks apart.

You already had the code. Take off the pan and check them.The worst thing is you'll change the trans fluid.

Caddyloversincebirth
04-20-05, 12:26 PM
I am definitely not one of the many great specialists that grace the threads of this web site. but i have personally had to do some work on my 4t80e tranny...sounds to me like you may just need to change your filters and fluid the kit for that is about $40.But, you will have to drop the pan any way so I would say spend the extra $70 on the shift solenoid kit. The little filter that sits between the A&B solenoids is not secured very well from the factory version and will move in and out. I think this could cause what your experiencing .the shift solenoid kit comes with a bracket to secure it better and a screw to replace the one that you will need to hold the bracket down.

JSMeloche
04-21-05, 09:14 AM
If i keep using the car this way will i grind blow my transmission? The tranny will only slip on light trottle, on medium to heavy trottle it shift correctly.

eldorado1
04-21-05, 02:03 PM
It kinda sounds like you have some junk holding open your pressure control solenoid just a little bit...
*****Sorry, I didn't read your symptoms close enough. I thought it was just slipping a bit, not grabbing hard too.. I think one of your clutch packs may be towards the end...



If i keep using the car this way will i grind blow my transmission? The tranny will only slip on light trottle, on medium to heavy trottle it shift correctly.

No, but realize that by continuing to drive it in this state, you will cut it's life expectancy down. Now it only slips on light throttle, but eventually it'll start slipping on medium throttle, and then it'll slip all the time. If your car has 30k, I wouldn't worry about it, but if it's getting up in mileage.............. Then you have a choice to make http://cadillacforums.com/forums/images/smilies/dizzy.gif

JSMeloche
04-21-05, 02:58 PM
grrrrrrr.... I need new tires and now this...

Shouldnt the computer throw some codes??? Its very sublte, a normal driver would probably not noticed it, i have to pay lot of attention to RPM and gear shift to notice it.

Ill bring it to the dealer next week, better to take care soon before my baby becomes criplled

eldorado1
04-21-05, 04:14 PM
grrrrrrr.... I need new tires and now this...

Shouldnt the computer throw some codes??? Its very sublte, a normal driver would probably not noticed it, i have to pay lot of attention to RPM and gear shift to notice it.

Ill bring it to the dealer next week, better to take care soon before my baby becomes criplled

What you're describing may be perfectly normal, hard to tell without actually being in the car. The computer won't set a code until it reaches the end of the pressure adjustment, and sets a "max pressure adjust" type code. Otherwise it thinks it's normal wear and just keeps upping the pressure to keep the slippage in line.

JSMeloche
04-22-05, 10:17 AM
I had the tire changed yesterday and now the car seems to shift great.... go figure. Just a slight stumble this morning on the first 2-3 shift but barely noticeable, maybee its just my imagination... N e way i wont be bringing the car in the dealer right away, I KNOW they are going to tell me everything is fine even if the test drive it.

No im on to shopping for new tires ;) I think ill get Yokohama AVS DB S2, i found some for 158$ CAN, great deal!!! Especially compared to the Pirelli P4000 my shop suggested at 363$can PER tire!!!

zonie77
04-22-05, 12:07 PM
1) If the solenoid is cracked, not broken, the computer probably will not show a code. At 100k I would change the fluid and check/replace the solenoids...especially since you got the code at some point. If you can do it yourself the cost is low, and it's good maintenence.

2) Does tire rack sell in Canada? tirerack.com I don't know what the exchange rate or any taxes will do to the price. Let us know.

JSMeloche
04-22-05, 12:31 PM
Ive checked Tirerack this morning, they do ship in Canada. But with the horrible Broker fee from UPS its not a good deal.

TireRack price for Yokohama AVS DB S2
574.45$ for tires
151.07$ UPS broker fee and 15% Québec Tax
+++$ for custom charge (i assume 50-75$)
Almost 800$

I can buy the same tires localy for 263$ each, - 102$ rebate = 161$ = 740.76 for all four with taxes

Shipping kills Tirerack good prices AND UPS has horrible service IMO, I prefer to boycott them after what they did to my last shipment....