TRAILER PULLING...

[voicepro]

...so tell me, guys...can I put a hitch on my '98 Seville and pull a small trailer...something, say, the size and weight of a pop-up?

Or will I have to give up my sweet old d'Elegance for a (Gasp!) truck? Thanks.

[airmike]

I have seen a trailer hitch on an xlr, so I am sure one can be put on that seville, though I don't know how to do such a thing.

I seem to remember something in the owners manual about towing also.

[Cadillac Jim]

You should check the owner's manual, but towing specs are often two numbers: total weight and maximum vertical force. The owner's manual should give you both those numbers, and the trailer specs should give the same numbers, probably on a plate fastened to it, probably on the hitch. That should tell you if the trailer size is within the towing capacity of your car.

Towing is never a really good idea for long hauls. It's harder on your transmission, as well as the engine and drive train, suspension, brakes, etc. Also, a trailer decreases acceleration, braking, and handling response, and the trailer may be far less stable than the car, so drive very carefully.

[Bruce Nunnally]

The 1998 Seville appears to be rated to tow up to 3,000 lbs.

[KHE]

A truck to tow a pop-up camper is overkill...

Use a frame mounted hitch - Pop-ups are fairly light so you should not have a problem towing one with your Deville. Keep the gear selector in "3" vs. overdrive. I towed a covered snowmobile trailer that weighed about 1500 lbs. loaded with my '97 Seville for years. You may want to add an auxiliary oil cooler for the transmission which is fairly easy to do. You plumb in the cooler to the transmission line output from the radiator and run it through the aux. cooler so the radiator tank pre-cools the transmission fluid, then it is further cooled by the auxiliary cooler.

[James Woods]

Just curious does the 1998 models have the 4t80e transmission? If so I wouldn't be worried about towing in overdrive. Just not something really heavy up a steep hill. My rule of thumb towing is if the transmission is hunting for the gear and shifting in and out of overdrive then I'll put it in next lower gear until I'm back to level ground.

I've towed a lot. From 2500lb motorcycle trailers to my 15,000 lb boat and trailer ( not with my Cadillacs of course) and have never burned up a transmission or had trans problems.

[KHE]

Keeping the RPMs up (by not using overdrive) will keep the transmission fluid cooler which is a benefit to the transmission and the torque converter. The viscous lockup torque converter in that era of car always has a slight amount of slip (<200 RPM) which generates heat. If the slip is greater than 200 RPM, the P0741 code will set.

[James Woods]

If the transmsion and convertor are working correctly when in lockup there is no slip. There is a small friction area in the convertor that locks up and becomes a constant connection like a clutch in a manual transmission and doesn't use fluid as a coupling. There for that's where the rpm drop comes in. If a transmission lock up solenoid stays on that would cause the car to stall when you stop like in a manual transmission in gear without pushing the clutch.

The p0741 code will set when the car is commanding lockup and does not see the speed of the input shaft match the rpm of the engine. If the speeds are different then the computer views it as the mechanical connection failed and the convertor is working off a fluid connection.

For fuel economy and emissions newer cars will lock up the convertor as low as 2nd or 3rd gear on a 6 or 8 speed automatic .

[KHE]

If the transmsion and convertor are working correctly when in lockup there is no slip. There is a small friction area in the convertor that locks up and becomes a constant connection like a clutch in a manual transmission and doesn't use fluid as a coupling. There for that's where the rpm drop comes in. If a transmission lock up solenoid stays on that would cause the car to stall when you stop like in a manual transmission in gear without pushing the clutch.

The p0741 code will set when the car is commanding lockup and does not see the speed of the input shaft match the rpm of the engine. If the speeds are different then the computer views it as the mechanical connection failed and the convertor is working off a fluid connection.

For fuel economy and emissions newer cars will lock up the convertor as low as 2nd or 3rd gear on a 6 or 8 speed automatic .

The 4T-80E of the vintage of the original poster used a viscous torque converter that has a silicone fluid that is the coupling fluid that allows a slight amount of slip in order to provide a smooth almost undectable lockup. When the seals in the lockup circuit would wear enough, the trans fluid would contaminate the viscous fluid which would greatly reduce its coefficient of friction which would allow the system to slip greater than 200 RPM and the P0741 code would set.

The 2000+ cars used a conventional torque converter lockup system that did not use the viscous fluid.

[James Woods]

The 4T-80E of the vintage of the original poster used a viscous torque converter that has a silicone fluid that is the coupling fluid that allows a slight amount of slip in order to provide a smooth almost undectable lockup. When the seals in the lockup circuit would wear enough, the trans fluid would contaminate the viscous fluid which would greatly reduce its coefficient of friction which would allow the system to slip greater than 200 RPM and the P0741 code would set.

The 2000+ cars used a conventional torque converter lockup system that did not use the viscous fluid.

I didn't know that about the older cars. Good to know. I've only had Cadillacs of 2001 or newer. The small things they engineer to make the Cadillac expierence. At least GM is not as bad as the Germans.

[Cadillac Jim]

Without slogging through the SI DVD, I did look at the Wikipedia writeup:

https://en.wikipedia.org/wiki/GM_4T80_transmission

They say that the TCC moved from viscous to friction "in 2004."

I recall an earlier version of this article that said that the 2005 model year is when the switch was made. The vagueness on this point in the article irritated me so I *did* bring up the 2004 FSM for Deville and it does have a slip rate table for the 4T80E for the 2004 model year.

If the FSM chart implies that a viscous TCC was sold for the 2004 model year, it doesn't mean that *all* 2004 4T80E's used a viscous TCC.

The 2005 FSM has a wholly different 4T80E section. The blurb for P0741 says that the TCC slip "should be near zero" implying a friction clutch. But it has the same slip rate chart as the 2004 FSM.

EDIT: I looked at the 2006 FSM and it *again* has the same slip rate chart. From the Wikipedia write-up, if the car is 2003 or older then the 4T80E has a viscous TCC. If it is 2005 or newer it has a ECCC (electronically controlled converter clutch, or EC3). For the 2004 model year, check using the VIN. Unless someone here has definitive information for the 2004 model year.