So, ever since my last tranny fluid change at 196K, my '99 L36 Bonne SLE has been suffering from the TCC solenoid not releasing (I forget the code) and the car going into limp-home mode. Its 221K now. When I asked about this before, the general consensus was that its friction material from the wearing clutches clogging up the solenoid. And that the tranny is on its last days...

Otherwise, the car still runs fine... but I'm weighing my options.

I'd like to swap in a rebuilt tranny... but since the engine has some improvements and may see more in the future, I'd like to find a affordable 4T65E-HD with a LSD. Is this going to be an issue with the L36 computer? I'd rather not have to get the computer reflashed (yet). Are their any affordable rebuilders of these trannies in the northeast?

I'd go used, but it seems like every used tranny I see is $600 and has 80K+ on it... ...or is not local to NJ.

Thoughts?

Do you have a 4t60, or do you have a 4t65e non HD trans in the car? If you have the 4t65e it'* a easy swap, if you have a 4t60 I believe you will need to add a wire. Call around to the local salvage yards. I just swapped one out for a guy and found a low mileage transmission for $500. Once I got the trans here I swapped out a hardened input shaft and installed a hardened 4th gear shaft. And also went with steel channel plate gaskets. If you want a LSD, that'* going to cost you. And to be honest, I think it'* a bad choice. The one I pulled was taken out in part due to the LSD failing. And Bill had 2 LSD failures.

It was my understanding that after 1997, all Bonnevilles used the 4T65E non-HD, at a minimum. Is there a definite way to determine this? RPO of M15 on the SPID, perhaps?

How much tear down do these require... total rebuild?

Hmmm... disappointing. What are the LSDs going for? What is weakness on the LSDs? Can the LSD be swapped in later, while the tranny is in the car?

I have been getting really sick of the one wheel spinning... it was bad before the minor tweaks... but traction has been a real problem especially on uneven pavement since. Every time it happens, I am reminded how much I like RWD cars better, regardless of how much I like my Bonne.

Where is the plug on the transmission? On the side, 4t65, on the front, 4t60

Get a guarantee on the trans, should be a simple drop in. Unless you want more out of it. Then you need only go as far as removing the valve body, this will give you access to the gears and input shafts.

I believe LSDs are going for $400+ Yes, they can be installed later on with the trans in the car. You just need to drain it, then remove the right side axle, the trans to engine mount, the right side torque mount, and the diff cover. Then push in and pull out the diff to get past the clip. Install new diff and cover and your all set.

A good used one will be the lowest cost option. However a good rebuild is worth considering.

At the moment, there are very few LSD'* on the market. Quaife and GMR are gear based LSD'* that don't have a repuation for failing. Clutch based LSD'* do. Intense had a few revisions and it seemed that LSD'* were problematic for them. EP still apparently makes them, but can take up to 6 months to ship the unit. But then, this is all moot because the only LSD'* I have ever found were built in the HD diff carrier or meant to be in an HD trans. That would be the final drive would be 3.29 gearing which your non-hd trans would never have been. Being that you don't want to reprogram (under 5 minutes for me as a semi local with an HPT) you'd have gear ratio problems if you tried to put in the different ratio.

On swapping parts into a trans. All the work Dan has done on a trans has been relatively straight forward swapping of parts. I have gone through a full rebuild and found it to be relatively easy. There are a few tools you should have and some advice etc. But overall it'* not a mystery. Perfecting the trans and knowing all the in'* and out'* comes from years of experience. However you could build one or swap parts into one yourself.

The most important thing when working inside a transmission is KEEP IT CLEAN. After that it'* attention to detail. Small mistakes can cause big problems. A ATSG manual is a must, as is a inch pound torque wrench. Bill and I both have mounting brackets to put a transmission on a engine stand. Really makes it easy to work on. But like Bill said, it'* not that hard as long as you can follow the manual.

My on-again-off-again search for a transmission continues...

What is generally the cut-off, year wise for swapping a 4T65E (or 4T65E-HD) into a '99 Bonneville? I'm finding it odd, but it seems like I'm coming across more mid-'00 4T65Es than late '90s 4T65Es... but I'm leery of how GM would have programmed/geared a tranny that came originally from a 3.1 or 3.4.

Unfortunately, dealing with the local junkyards ended up being a run around... everyone wanted big money and insisted I buy a '99 Bonneville 4T65E, as they claimed it was the ONLY one that would work.

All my local junkyards are wired together... which sounds great, they can track each other'* parts... but it seems like instead of helping, it just helps them form a cartel and fix prices. Worse, each one wants a huge core charge... bad, since I wanted to hold onto my tranny for future rebuild possibility. Looks like eBay for me.

Any H-body 4t65-e will fit a H-body that came with a 4t65-e this includes Bonnevilles 97-03 (04-05 I'm not too sure about) I have a 97 bonneville that I am putting a 2000 trans into. The only things I need to change is the passenger side axel cause I'm going HD and add the trans wiring because I'm going from a 4t60 to a 4t65-HD

I'm not entirely sure if there were differences in H-body transmissions, but I know for a fact the W-body 03 transmission is different from the 02 and older transmissions internally. There'* a different PCS that the PCM is calibrated for (FMC values for line pressure), and the valve body is also designed for that PCS. Save yourself the trouble if this at all applies and get a 97-02 transmission.