Need Help..... first breakdown :(

[M3S2k]

Ok, so I was left somewhat stranded today in my Esprit. Drove into the city with it and was sitting at a stop light. Light went green and I proceeded to take off. Not aggressively, just casually. Right away I heard a loud thumping noise coming from the rear which got louder as I accelerated. I continued down the road another 1/8th of a mile until I could safely come to a stop out of traffic and did a quick little diagnosing. Could not see anything. Clutch still felt good and strong, engaging and disengaging as per usual. Transmission shifts through all the gears without trouble, feels exactly as it always has. Anyways, left the car parked there and trailered it home later on. Now I am hoping it is just a CV/ Universal joint in one of the drive axles and nothing in the transmission. It seemed to make the noise in any gear. I am wondering how it just started all of a sudden with no earlier signs, though. There was no loud bang or anything. Anyone have any ideas? I nervously await anyones response. I really hope it is nothing extremely serious!!

[redshift]

Sounds very strange. Is the thumping noise speed related or rpm/gearing related?

[M3S2k]

seems to be speed related. Thumping got faster as I sped up.

[wpowell]

I had a similar noise from mine, just came on all of a sudden. The noise from mine came on whilst I was up in the Lake District last year but I managed to limp home on the motorway at a constant speed in the slow lane.

Check your near side (UK) rear wheel bearing for tightness, this should be torqued up to 200lbft (260-270Nm) mine kept slightly coming loose but when it happened this time I decided to change the bearing and put an additional lock nut on. Had no problem since.

Jack it up with it out of gear and hand brake off and try the wheel for play, if you find any play the centre nut from the drive shaft could be loose or the bearing may have failed

Good luck

Will

[M3S2k]

Ok, so did a couple mins of trouble shooting this afternoon. Seems that it always makes the noise, but it definitely seems louder when in gear and driving. I also tried rolling it down a very slight hill in neutral with the engine off and the sound and vibration is there, but less noticeable. I am starting to think it might be something transmission related. What exactly is all turning inside the gearbox, related to the car rolling not the engine running, when the car is in neutral? I am wondering if something happened to the differential.

[Bibs]

Silly question perhaps but have you checked the tyres for delamination, a chuck of tread may have been cut loose by a stone? It happened to me some time ago!

[M3S2k]

I am pretty sure it wouldn't be tires as the thumping sounds too loud and harsh to be tread missing. I will have a look, though. Thanks.

[M3S2k]

Alrighty, Just got off the phone with the Lotus guy at Viking Motorsports and he has informed me that the problem is most definitely a chipped tooth off the crown wheel. So it sounds like I will be needing a new crown wheel and main shaft and the other bits that go with that. He has quoted me about $3500, for the crown wheel and main shaft. Is there anywhere else I should be talking to for pricing? Thanks

[peter_england99]

Not good news. Sounds like it would be worth going for one of the available gearbox upgrades. Then hopefully you will have a gear box capable of handling the V8 torque.

Regards,

Peter.

Alrighty, Just got off the phone with the Lotus guy at Viking Motorsports and he has informed me that the problem is most definitely a chipped tooth off the crown wheel. So it sounds like I will be needing a new crown wheel and main shaft and the other bits that go with that. He has quoted me about $3500, for the crown wheel and main shaft. Is there anywhere else I should be talking to for pricing? Thanks

[M3S2k]

I think I will be doing that in the long run. In the mean time I would really like to find a used gearbox to use for the summer. If anyone knows of one for sale, please let me know. I would then like to rebuild my gearbox over this coming winter and upgrade everything so it will be bulletproof. I mean I knew that these gearboxes were fragile, but I am paranoid like crazy now. Can't even take off from a redlight without something breaking!!!

[scuba1099]

I just had this problem. I lost 3 teeth on the crown wheel. Unfortunately the teeth ended up getting jammed in the gears ruining 2,3, & 4. I didn't have any warning, just took off normally and when I upshifted to third all hell broke loose. The diff ended up jamming at 45mph. I'd be careful with that thing, it could end up worse than it is now..............

[M3S2k]

Yes, this is what the mechanic at Viking warned me about as well. Since this happened I have only driven it on and off the my trailer, so I hope the damage is not more serious than just the crownwheel. At this point the car shifts perfectly through all gears and no jamming has occured.

[M3S2k]

One positive to this whole thing is it looks like it will be 10x easier to install my test pipes with the transmission out

[M3S2k]

update on the progress:

July 2nd

- Transmission was reassembled within 3hrs of crown wheel and pinion arriving from england (huge thanks to Bibs for helping me arrange for this!!!).

- When sliding bellhousing noticed that input shaft was binding and found out that the problem was with the guide tube, it was bent

- After numerous calls Harry at Viking Motorsports graciously sent me a guide tube out of a disassembled transmission he had in exchange for me ordering him a new one from JAE.

July 8th

- Guide tube arrived July 8th

July 9th

- Bellhousing reattached to transmission and reinstalled into car

For tomorrow:

- Oil filled into transmission and oil change for the engine.

- Install exhaust and tighten test pipes to turbo mounts

- Recharge A/C from last years A/C compressor replacement

- Go for one hell of a ride smiling from ear to ear!!!!!!!! (provided everything goes according to plan)

Edited July 10, 2008 by M3S2k

[act2007]

Steve,

Let us know how it works. I'm waiting to see how your new "exhaust" system sounds like!!!

Alan

[M3S2k]

Hey Alan, the test pipes have already been removed as I could not get them to fit properly. Now does anyone know if that sensor in the oil drain plug on the engine has a crossover to another part? Need a replacement, dropped it

[M3S2k]

Happy to report that the car is finally mobile!!! Went for a short rip and man did it feel good. Gave it a quick was as well, now time for a full detailing. Did an oil change while i was at it and happy to say that there is no coolant in their. The coolant looks to have just been low. Topped up and temps were fine on the drive!!

[redshift]

Happy to report that the car is finally mobile!!!

Good news Steve, that must have felt like a long three months!

Was there any comment about how the damage could have happened?

[M3S2k]

The mechanic who helped me lift the transmission back in said it was most likely from some previous hard driving. Probably some major holeshots or extremely abrupt downshifts. He figured the teeth had been fractured or fatigued at some point and just finally gave way, lucky for me it was leaving a stoplight so was driving very slow and no other damage occurred.

[M3S2k]

one thing I forgot to ask, is there anything special we have to do for break-in on a new diff?

[M3S2k]

After driving the car for a couple of days now, I have come to the concensus that the car doesn't feel as zippy as it did before. It still goes pretty good, specially at lower speeds, but once you try and wind it up it doesn't seem to accelerate nearly as fast. This have to do with new diff needing time to break in or too much pre-load? I do hear the turbo's spooling so don't think theres an issue there.