It's true, my Jaguar now goes forward as well as backwards!

The dreaded Delayed-Engagement monster devoured the forward clutch assembly in the 4L80E.

There was only a little warning of trouble, a slip during a rolling light accel. Parked at Circle K as normal, then backed out of space. Goodbye forward movement! Luckily I was close to home and it was nighttime, so I was able to get Back home using the Back roads in my Back-up Jag.

Transmission shop experience in a tiny nutshell: started off real well, ended up very troublesome. Basically they had to do the job twice over the span of six weeks.

Actually there were a few random occasions earlier this year when I got a weak engagement to Drive and a heavy shudder when launching, which self-corrected as I let up on the throttle. Then normal perfect function.

No more delayed engagement to Drive! No more harsh engagement into Reverse! I'm just $3000 lighter. But I guess I'm happy now.

 

Since I am certifiably insane and spending quite a bit of time fettling and adding consumable parts to my 96 car I keep wondering what will go wrong next, and had 4l80e rebuild kits bookmarked.

Hs anyone ever tried doing a rebuild of these? I'm assuming there is a Jag specific bellhousing etc, any other quirks? This reminds me I must change the tranny fluid! Amsoil is really expensive (currently 120 bucks per 2.5 gallons and it takes 13.5 quarts for a full flush) - any product recommendations anyone?

 

I didn't get an answer about exactly what kind of fluid the shop used in my rebuilt unit. I will ask again. Although it might only be bulk barrel of whatever was cheapest at purchase. Throughout my ownership I was using Valvoline Max Life multi-vehicle synthetic. It worked really well. I don't think it was the cause, if the forward drum is going to let go there is nothing that can be done about it. The delayed engagement was present regardless of what I did throughout my years with the car, and was a manufacturing defect. Hence the orange dot upgrade on later cars.

For sure it is advisable to at least replace your valve body with a rebuilt. There are a lot of wear (weak) points within it and with poor fluid control you are at a disadvantage. @John Baker used one of these: Worldwide Valve Body for the 4L80E.

My biggest problem with the repair was the torque converter. It was botched at the first go-round. Although my shop did not rebuild it (it was contracted out for rebuild) it had to be replaced again, at their expense. Transmission out again. So don't rebuild your torque converter if it is ok now. There are a lot of HACKS out there who can't do a very important job right. Even with a TC as common as the 4L80E.

 

Thanks for the info. My car is an orange dot car with a tranny that shifts flawlessly (touch faded wood) and (again (touch faded wood) runs very smoothly which is why I bought it, but i've been spending a lot of time at picknpull recently getting backup spare x300 parts and missing bits for my still quite shabby 96 car. I'm acutely aware of weak points and consumables as the car gets older and the trans is sure to be an issue at some point...

 

Out of curiosity, was your harsh reverse engagement followed by a delay, or was it immediate? Mine sometimes has a harsher engagement into reverse with zero delay which was identified as "something in the rear like U joints" in the PPI I had performed.

 

Most of the time my Reverse engagement was like a kick in the butt. As if the ball valve #9 was missing that slows the pressure build-up into reverse. However it was always immediate. True, a bit of play in the differential or U-joints could contribute to some harshness, but now my car is much better after the transmission rebuild. Ironically, engaging Reverse directly from Forward gear used to occur very smoothly and promptly. Seems if the Forward clutch was already engaged, the system had the correct pressure feeds for Reverse.

The delay into Drive was always present no matter which range I was coming from. About 4 seconds, seems like forever when you are waiting for it!

Next time I'm down there, I'm going to stick orange dots all over my new transmission! We deserve it.

 

Someone such as yourself Oliver, could probably rebuild the 4L80E just fine, working very carefully and TRIPLE checking everything that you do. I think the hardest part would be removing and installing the trans from the car. If you have a lift and a transmission jack you are ahead of the curve. Internally it is identical, as it should be in order to be named 4L80E! This would be the first gen used through 1996 I believe. Later gens changed the cooling line fitting locations, among other things.

The trans housing bolts directly to the engine and although it looks considerably different to a regular 4L80E it's not.

The torque converter is a different story. It has it's own identity. It is a specialty within a specialty. It needs special equipment to cut it apart, and then to weld it back together. If an error is made internally, again it has to be cut apart. Of course it needs to have the transmission out of the car to remove it again, and this was my unfortunate case.

The greatest caveat is that without very specialized equipment, a rebuilding error made anywhere within the system cannot be discovered until it is ALL back together. That is where I don't understand where my shop went wrong. No one tested the torque converter after the rebuild!?! It was seriously off-balance, causing massive vibration in the vehicle when driving after the job was "finished".

 

To answer Oliver about rebuilding transmission yourself…. Go for it.

The 4L80E is kissing cousins with the TH400, and I’ve done one of those without a problem! I used the TH400 version of this 4L80E book: