I had 2 D2's I had to diagnose come in with a "rumble when driving" and it seemed to carry on into the D2 as a vibration while another complained the engine was rough when revving it up past idle and it shifted rough.

First D2 owner was told oh your transmission is toast. They even went to a junk yard and bought a used HP24 for me to install just in case. It felt like broken engine/transmission mounts, but those were fine. I even checked the harmonic balancer because it was just that rough. It felt like the engine/transmission/TC were just about to fall out from all the vibration/rumbling. Fluid in the transmission wasn't the best, but it certainly wasn't the worse I'd seen. I went ahead and told em I'd tear it down more to see exactly what was going on. Well I got to the point of separating the engine/transmission and when I got em about 10mm apart it sounded like I broke a wine glass. The darn flex plate was in about 1,000 pieces. The only thing that was holding that giant puzzle together was the TC being bolted down. Once the 4 bolts were loose and I then separated it all just fell inside the bell housing. I informed the customer and they said to go ahead and replace the transmission since I was at that point anyways and to replace the 25.00 flex plate. Slapped it all back together and no more issues. The HP24 I removed the customer let me keep and I've since installed it into another D2 (trail truck) and the transmission is fine.

Second owner complained it would lurch into gear from park, and it just vibrated, rumbled, and any RPM's over 1.2k made it feel like the D2 was going to break apart. After having the other one only weeks before this one the silly flex plate was still fresh on my mind. I removed the 4 bolts for the TC and as soon as I did I heard a cracking sound. Got my inspection camera up inside the bell housing and sure enough their flex plate was also in pieces. Informed the customer, got approval for the work, and got the Transmission separated from the engine to find the flex plate had basically broken free around the 4 bolts, but somehow managed to bend and make teeth. When you'd go from park to drive it would slip not catching on anything then it would come across the spot where the flex plate was bent and engage. Put in park and go back to drive it would repeat the process and feel like it was lurching. The vibration was due to it only grabbing onto 1/2 inch of steel vs the entire surface of the flex plate. Owner said it had been like that for years and had finally just got worse and worse lol. I'm amazed it didn't grenade just accelerating onto the freeway!! Slapped on a new flex plate and that D2 was like new.

Yours could be cracked around the 4 mounting bolts (common spot & hard to detect without tearing into it) Or it's like the 2 above where it's just being held together by a wing and a prayer. It's a cheap part like 25.00 for the Britpart version, 60.00 for the Proline version, and I think Ashcroft still sells a HD version for about 100.00. Just something I thought I'd mention as the first customer for sure thought their D2 had serious transmission issues and it was just a 25.00 part with a lot of labor cost!

 

Thanks, "Beaumont", could be a possibility.

It does feel like something is slightly "out-of-balance", but no where near as bad as the two you've described above.

Why the failure? It seems like metal disintegrating is more a problem with cast parts than with the rolled steel of the torque plate (which I would expect would simply shear rather than crack)?

I have a good quality borescope, so wondering where I should inspect first: through the inspection port on the bottom of the bell housing or through the torque plate bolt access port on the front side of the housing (the one with the rubber plug in it?

And just inspect at the mounting bolts?

If I need to replace it, do I need to pull the engine or the transmission, or can I just de-mate them, loosen the motor and/or transmission mounts and slip it up thru the gap? I clearly recall the four(?) bolts holding the torque plate to the TC, but I can't quite remember how the torque plate afixes to the flywheel.

 

One other thing.

About 4-5 months ago (late March, on a drive from Austin to Houston), I had the front driveshaft start to "go". It made some awful sounds when accelerating/under load that went away once I reach a constant velocity.

I first assumed it was the transfer case, but I first removed the front driveshaft, and found that the "Hooke" double joint was sticking/clicking badly (I had rebuilt that joint 6-7 years ago when we did the engine rebuild and has a lot of trouble getting it all back together, especially at that internal ball-and-socket, which, reading the RAV, is not serviceable, so guess I screwed that up).

I picked up another front driveshaft up from the junkyard that seemed good, but now not so sure for a couple of reasons:

1. The Hooke universal joints on my junkyard replacement have grease fittings on them, but the RAV says that the Hooke is permanently greased/sealed and needs no maintenance (so shouldn't have grease nipples, right?) so maybe my junkyard find had also been (poorly) rebuilt?

2. I can't recall checking whether this driveshaft came off an 03-04 with an HP24 or off an earlier D2 with an HP22 (didn't check . The RAV says that the 03-04 front driveshaft is modestly shorter (0.6"), so maybe I put the wrong length driveshaft.

I am guessing that the spline at the u-joint at the front axle would accommodate the shorter length, but I am wondering if maybe when I had the beast up on my buddy's lift, that somehow the complete extension of the suspension when it was fully suspended took the spline beyond its limit (it was the first time it had ever been fully suspended under my ownership, I was surprised at how much range the suspension had).

Only good news is that I know that the front driveshaft has not worked its way loose as I marked all 8 nuts-bolts securing it to the axle-transmission with nail polish ($1 at dollar store -- sorry, now the $1.25 store -- I have like 10 colors to mark things, much better than a $5-10 paint pen), so I know they haven't moved/loosened.