Dragging this one back into focus. I took the machine to the garage that I bought it from, a bit of a funny outfit but man they know their stuff. Probable should have gone there first. The car was subjected to a range of driving tests to try to show up the problem. Then it was on the lift and the front wheels raised for further tests.
Diagnosis. Either the front knuckle joint on the prop is siezed so that when the engine pitches on load the front shaft and the front VC bearing are dragged downwards, or the CV on the front on-side drive shaft is defective that is affecting its balance. Other observation is the oil leak (that I knew about already) of this on-side drive shaft output from the gearbox is significant enough to warrant replacement before it drains the gearbox of oil.
Engine health - Performance excellent, nothing of concern.
Solution. The prop shafts and VC was removed completely and inspected. the front knuckle joint was not siezed but there was slight play in it. Maybe enough to cause vibration. I then drove the car in Mondo mode to see what this had done.
Result - Reduction in noise was remarkable. Handling was not as good as the car felt very nose heavy, like it wanted to understeer. Pulling away from junctions brought the traction control in, which I was surprised at as I wasn't exactly booting it. Engine braking much reduced. Fundamentally, although the hammering and vibration had reduced I could still feel and hear it as before. Decided I didn't like Mondo mode in theory or in practice.
Next step. The prop shaft was replaced. A lack of a new oil seal stopped the days proceedings. The garage has a replacement driveshaft (not new). the plan is to get a new oil seal in then replace it and the driveshaft in one hit. Then we try again.
Due to the lack of staff during this Christmas working period I was left by myself in the workshop while the phone was answered. I took the opportunity to grab the lamp and carry out a detailed inspection of the underside of the car. Everything was satisfactory with the following observations.
Rear diff bushes in order, stressing revealed no weaknesses.
Rear diff - Next to no backlash on the input shaft. No oil leaks.
Rear driveshafts, fine - no detectable play in any plane.
Underside body work fine.
Brake lines fine.
Fuel lines and tank, fine.
Exhaust, generally in good condition. One bracket completely missing on downpipe from turbo to cat. Enquired about this and assured this was not of concern. Tend to agree as there is plenty of other support.
Rear suspension linkages and bushes, fine
Rear sub frame, small amounts of surface rust in places. Needs some Waxall.
IRD rear output. Significant backlash in the gear train, however, having looked at the number of gear stages this would seem to be unavoidable. Testing did not raise any concerns with the IRD as yet. There is an oil leak in this area but it was difficult to see where from. It was not significant.
Rotation of front wheels in free air revealed no obvious notchiness.
Front wheel bearings, no detectable notchiness or play in any plane.
Lower suspension arms and bushes are in good condition.
Front subframe, good condition.
Gear selector shaft. Oil leak on interface to gearbox, not serious.
The significants of all this is to determine how much I invest in this car. I believe there is plenty of life left in it and think it worthy of repair. Sentamental old sod....
Thus ends this report. I will report on progress when the driveshaft is replaced, hopefully next week.
Dunno how that got there...
