The 4t60e trans in my 1997 buick lesabre has been rebuilt once before and is now out of warranty. Its starting to slip and I'm thinking about getting a second trans from a junkyard to rebuild or a remanufactured one.

My question is can I swap a 4t65e or 4t65e-hd for the 4t60e? It appears like that'* not easily possible without changing pcms and the wiring harness and such.

If that'* not possible is a 4t60e-hd swapable? Or is there extra work involved in swapping parts there as well?

It'* not going to be easy. 1997 was a transition year for the LeSabre'* transmission. You are correct that a 4T65 won't go without major wiring changes, PCM, etc. A 4T60E-HD miiiight, but you'd want to try with a 1996MY, even then it would be an experiment to see if you can get it to work, if it has the right connections, and if the -HD (assuming from a junkyard) is any good in the first place.

If the -HD isn't from a junkyard or you are getting it rebuilt before installing, you'd be better off rebuilding the 4T60E-notHD with some upgrades.

Curious: How many miles on the car? How many miles since rebuild?

Almost 153000 now. Was originally rebuilt around 130 I think. Though it went back to the shop for warranty work between then and now. What are the upgrades you're suggesting for a 4t-60e rebuild? I'm not very knowledgable on transmission rebuilds.

20,000 miles and it needs another rebuild? I think the first shop screwed you.

You would do well to get the trans go kit.

It would be beneficial to scan your rebuilt transmission for any codes. Beside slipping, does it offer any hard shifts or clunk between 1-2 or 2-3 gears?

. . . and a warranty claim in between rebuild and 20,000. Wow.

More clutches, improved parts, harder/stronger parts, better materials. Some shops will do it, others rebuild every transmission the same from the same rebuild kit(*). With a 1997 LeSabre, unless you are adding power or will be driving it hard, you don't need to worry about all the crazy beefing up they do for modified supercharged engines in Bonnevilles and GTPs etc. It'* more important to get the improved parts in there and fresh wear items and gaskets.

"Improved parts"= parts that were known weak after leaving the factory that the aftermarket (and sometimes the factory) designs a better version.