Thread: '99 GTP 4T65E-HD seems to have died.

My sister has a '99 GP GTP, with the supercharged 3.8 and 4T65E-HD. 130K mileage.

It has been driving fine... east coast to west coast and back a couple times... but on its last trip it kicked out a P0742. In the last 9 months, it kicked out maybe 2 more. With my experience with my own dying 4T65E (non-HD), I figured the tranny was slowly dying (mine hung on for 30K).... but in the case, the tranny just shutdown completely this weekend. No forward or reverse gears... after a short cooling period, it drove a few more blocks before repeating the problem. When the tow truck driver showed up, the rear brakes seemed to be locked up. ?

Thinking it was a sticking brake, not a bad tranny, it got towed home. Today it was being limped over to a shop to check out the brakes and the tranny dropped out again. No forward or reverse gears. The normal shop told her to take it to a tranny shop... it got towed there... the guy took it out for a drive, it died again and he claims that the torque converter is bad, likely leading to a bad pump and total contamination with burnt fluid. Bottom line: needs a rebuild, and quoted $2K. Only test driven, didn't drop the pan or even hook any test equipment up.

Now, I'm 3000 miles from the car, but the fluid was slightly dirty but not burnt when I last saw it last August... and my sister didn't feel it smelled burnt this weekend. In all the years of banging on cars, I've never had a torque converter go bad... and with the symptoms exhibited so far, I would have liked to see the filter changed or checked first before determining it needs a full rebuild. I accept that it will need rebuilding at some point, but I am not feeling satisfied by the diagnosis here.

My next concern is that with such a knee-jerk diagnosis that I have to worry about a rebuild being done correctly... I'd hate to have the 4T65E-HD rebuilt into a 4T65E.

Anyone know a good tranny shop in the Los Angeles area?

BKNJ

I get where they are coming from... if the tranny is removed from the car, its getting a rebuild... but their reasoning doesn't jibe with my experience and quite a bit of reading about the 4T65E over the past 2 years. The car does move... one needs to let it cool or sit for a moment... then it moves for a few hundred feet or a couple miles.

After 30K of P0742/P0741 codes on my '99 Bonneville 4T65E when it did this drop out stuff, a replaced filter got it moving again (doesn't solve the codes, though) for some time.

BKNJ

Originally Posted by Jevik

The only big difference between the Hd and regular is the differential and the passenger side cover. So it's not likely to be turned into a regular 4t65e. I would sooner get the TEP rebuilt tranny for $1375 shipped and have someone drop it in when it arrives than pay out 2k for a rebuild. It may end up costing the same, but with TEP you know it's done right...

The differences between the 4t65e (M15) and 4t65e-HD (MN7) also include a stronger input sun gear and roller bearings on the diff, in addition to the larger diff and passenger-side cover. I also believe the chain drive is also different, which give you the different final drive. The shop the car is currently at, the dude seems to have no clue of the difference between the two. This casual indifference to what gets installed has burned me before... when I specified that I didn't want a new rear installed unless it had an LSD... and that I wanted the old rear back. I show up and my old rear is in the trash and the car is a one legger... because most people don't give a crap.

TEP is an option, I suppose. It took a while, but I finally found the $1375 on their website. Does this really have no core charge? While its a shipping nightmare, I'd love to keep the original transmission.

BKNJ