A little late on the reply, but here'* what I know (I am familiar with these cars/drivetrains, but by no means do I know it all).

As from what I've heard/read the 4T60E was available until 1997 in the non-supercharged 3800, 3.1, 3100, and who know'* what all else.
The 4T60E-HD was available 1992-1996 on the supercharged 3800 (and maybe the 3.4 DOHC in GTP and Z34 and so equipped Cutlass Supreme'*). This HD version of the 4T60E was standard, and the ONLY transmission used with the supercharged 3800.
In 1997 the 4T65E-HD replaced the 4T60E HD in supercharged applications, but in the non-supercharged 3800'* the 4T60E non-HD remained, although the Park Avenue and Riviera did get the 4T65E non-HD a year before other L36 (non supercharged Series II 3800'*).

You are correct about the ID #'* of the trannies. One difference though is although they are both 4-speed (forward) transmissions the 4T60E is a 3 spd, with the 4th gear being an overdrive (notice the gear selection difference between your 1996 and your brothers 1997), and the 4T65E is a true 4-spd without OD.

As for Gonneville'* info he is correct, if you have an L36 - the 1997+ L67 (Series II supercharged 3800) only had the 4T65E-HD. To put an HD tranny in a L36 car would require PCM work to program for the HD gearing (which IIRC is 2.93 and the 4T65E non-HD was available with 2.84, 3.05, and 3.29 gearing -3.29'* being available only in Grand Prix GT'* and maybe Regal LS'*).


I forgot about this site when listing tuner'*, but for your 1996 you might be able to find someone to reprogram your PCM at www.L67swap.com as there are a few people who have swapped SC'ed 3800'* into other cars, namely Fiero'*

What is the L36 and the L67? I assumed the L67 was a series II and the L36 was the series I . If that'* correct, I should have the L67, as mine is a series II.

Also, are you suggesting I also have the 4T60-HD? I would be happy to hear mine is a heavy duty tranny. I looked at my tranny after noticing the fluid level was perfect, and the fluid was clean, and I noticed it wasn't the original, but rather, it'* a GM rebuild. Looks pretty clean too. Not corroded or dirty. I'll have to find out exactly which one it is, unless I read your post correctly, and it'* a HD version of the 4T60 .

Thanks for the link for the L67 swap . I'm going to check it out now....


"EDIT" , I see after a search, the L36 is the non-supercharged 3800 engine I had in my last 2 bonne'*... Doh....

OLBlueEyesBonne,
OK, I read your post a few times before Fully understanding it, but now I think I get it.. lol

Am I to assume my brother and I both have the HD version of the tranny'*...mine being the 4T60-HD, and his being the 4T65-HD ?

Also, is it safe for us to be happy we have the more durable transmissions? or are these HD'* just as prone to failure? I drive much easier than he does...... He'* pretty hard on a car. Would it also be safe to assume GM installed an HD in my car whenever the tranny was replaced?

I'm getting happy now, since I always thought the supercharged bonne'* had the same tranny as the non-supercharged...

Oops. Sorry for any confusion. Didn't mean to but sometimes my replies can get kinda drawn out.

Yep, every supercharged 3800 came from the factory with the HD version of that years tranny, 1997 being an odd year with the standard L36 having the 4T60E non-HD and the L67 having the 4T65E-HD.

Also, you will find there are quite a few people here who would say you have the best combo of power and reliability -the 1996 Series II supercharged with the 4T60E-HD which was less prone to problems than the 65-HD.


Also, here'* a break down of 3.8/3800 engine RPO codes:

LG3 1984(?)-1987 3.8
LN3 1988-1991 (VIN C) Series I
L27 1991-1995 (VIN L) Series I non-supercharged 3800 Tuned Port Injection
L36 1995-2005 (VIN K) Series II non-supercharged
L67 1992-2005 (VIN 1) Series I and Series II Supercharged 3800
L32 2004-2005 Series III Supercharged 3800

There is also the 2004/2005 nonsupercharged Series III 3800 but I am not sure of the VIN # or and can't recall the RPO code.

If I didn't answer anything here let me know. And if you have anymore questions I'll gladly answer them as best I can.
Also both versions of the Series III 3800 are available only in the Grand Prix.

OLBlueEyesBonne, You have given me a lot of info today. Thanks. I'm happy to hear I have a great combo. I certainly wish I would have visited this forum a long time ago when I had my older bonne'*.

I don't have any other questions yet, but I will soon. I have a few things to get sorted with this car, but I'm not quite ready yet.. I'll keep browsing the forums and a thought will occur, and I'll be asking...

Thanks again... Sam

OK, I was chatting with my brother last night, and he asked....What are the pros and cons of the 4 speed tranny, and the 3 speed with OD?

Let us know about reliability, performance, economy, smoothness...etc. And, why did GM have these 2 setups? We have become used-to having OD transmissions, and don't understand if the 4 speed is better, or worse.