Transmission slipping when warm

Mchurch68 · #1 (**permalink**) 11-13-07, 12:05 PM

Hi Everyone,
I have a 2000 DTS. Car runs fine when cold however when it warms up the tranmission starts slipping. Any thoughts on what it might be?

panej · #2 (**permalink**) 07-03-08, 10:35 AM

I currently have the same problem. Were you able to determine the cause?

codewize · #3 (**permalink**) 07-03-08, 10:46 AM

Mileage ? Service History? Codes?

panej · #4 (**permalink**) 07-03-08, 11:08 AM

135K miles. Bought used last year. Don't have history or codes.

codewize · #5 (**permalink**) 07-03-08, 11:14 AM

Does is slip at all speeds? All gears? Or is the slipping only over 40 MPH? I'll assume you've checked the fluid for level and integrity?

These transmissions are pretty durable and long lasting unless you start putting 400+ HP to them.

misfit6794 · #6 (**permalink**) 07-03-08, 11:15 AM

Have you checked the fluid level? Check it with the engine hot or idling to make sure you have enough in there. Also look at it to see if it is very dark or has any metal flakes in it.

codewize · #7 (**permalink**) 07-03-08, 11:41 AM

At 135k you're almost guaranteed to have some metal in the fluid but yes, hold the dipstick out in the sun so you can really see any reflective material in the fluid.

There are numerous magnets and filters in the 4T80E so most of that should get caught unless there's major failure.

But let's first try to pinpoint WHEN the slippage is happening

panej · #8 (**permalink**) 07-14-08, 01:55 PM

It usually starts after it warms up. Happens at any milage. SOmetimes would not engage right away from a stop position. Also jerks when it engages (also only when warmed up) Fluid level is fine, but I noticed a half empty can of ATF that is not dexron in the trunk from the previous owner.

thaghost87 · #9 (**permalink**) 07-14-08, 02:15 PM

I have this same problem.. after driving the car for a while, and it heats up, i start to get a harsh gerk into gear. it happens for all gears. I had all three engine moounts replaced. I get a first and sometimes a second gear ratio code. I have the correct trans in the car(not an sls or eldo). Still dont know why i am having this problem.

Lithorian · #10 (**permalink**) 07-15-08, 01:12 AM

pressure drop when the fluid gets hot, put a bottle of lucas trans fix in and see if it helps, if so, drive it till it breaks really, not much else you can do except a rebuild

codewize · #11 (**permalink**) 07-15-08, 08:39 AM

Hmm I think we need a tech in here. I don't know enough about transmissions to take a stab at this.

Could be a pressure problem but there has to be something specific that causes the 4T80E to respond like that.

I honestly have never heard of one slipping before. If no one jumps in here I wold take it to a REPUTABLE transmission shop just to get an opinion. NOT AMMCO or any of those guys.

I've found that dealers are usually right on the money with this stuff but that may cost you $40 - $50 for diag.