My new '98 Bonneville is in great shape, but it has 160,000 miles on it. The transmission shifts well, but sometimes it feel a little shifter shock here and there (normal?). Besides accelarating slower, is there anything else I should do to make sure this transmission lasts? I have heard these 4T-65E Tranny'* aren't all that durable?

I know it seems obvious, but I'd suggest changing the filter & fluid, waiting 1-2K miles & changing just the fluid again: it made a noticable difference for me

and on the fluid change, put in a quart of Lucas Tranny Fix

how about adding an extra trans cooler? would that help?

put your car info in the sig area, including trim level. you might already have a tranny cooler on your car, won't hurt to add one if you don't. Monitoring temps with a scan tool will tell you if you need one.

First thing first though, drop pan, replace filter, replace atf and add a bottle of Lucas.

IS the 4T-65E really as unreliable as I've heard? Maybe I am just worrying for nothing, although I do have 160,000 highway miles on the drivetrain.

Most will tell you that you are on borrowed time. Look at my 97 SSEi. it has the original tranny without any rebuild. YMMV

This transmission shifts incredibly smooth, the only time I can ever feel it is 1-2 about 60% of them time, maybe 3-4, but its all rather subtle, probaby normal. In my old Cutlass Supreme with the 1980'* 44T04 Transmisson, that had 170K miles on it, and the TCC clunked a lot, but it till was reliable. I just want this car to last at least another 20K miles.

mr. I got 2 billion miles on my car I drive like it was stolen lol.

I do agree..put some of that lucas tranny fix stuff in there. I have yet to blow a tranny that did not have problems already to begin with.

one wheel burnouts are the biggest no-no. take it easy off the launch...if the car gets hot (tranny probably getting hot to) take it really easy on it.

You are getting good advice. #1 transmission killer is heat. Certainly Install an external trans cooler if your car doesn't have one, and, even if your car does have a factory cooler, consider increasing the cooling capacity for your trans by replacing it with a bigger one. I recommend the same one willwren uses. I installed a smaller size from this company, and saw great improvements, but now I wish had bought the same one Bill recommends - this one:

http://www.bulkpart.com/Merchant2/me...roduct_Count=4

Consider installing a drilled 180F thermostat to further lower drivetrain temperatures. With the engine and trans running cooler, everything will last longer.

Drop pan, clean, change filter and refill - will change about half the fluid. I do not recommend trans flush because of the possibility of major trans damage when not performed properly. Safer and cheaper to drop the pan yourself. If the trans is shifting OK now, I would not add anything but Dexron III. I have had some success with additives in weak transmissions that were on their way out, but I would not use them in a good trans.

Also good advice on the easy driving. I have babied many a car with weak parts and gotten many more miles out of 'em. You cannot routinely do hard acceleration and expect any transmission, strong or weak, to last as long as if you drove it gently. Driving hard and fast reduces the life of bearings, axles, brakes, suspension parts, tires, fuel economy, and driving privileges.

If your engine is an L36 (non-supercharged) read this topic:

http://www.bonnevilleclub.com/forum/...e=article&k=38
Do this repair work BEFORE the LIM gaskets or the UIM fails and damages your engine.

This, and frequent oil changes (not by Jiffy-lube) ought to keep your '98 running for a long, long time.