Hi All from South Africa,
I have been reading the posts on this excellent website for some time and have learned an awful lot and now I am confronted with a problem on my 2000 Pajero LWB that has me completely beat. My car is a Generation 2.5 (Blister Fender) with an automatic transmission and the 3.5 DOHC motor (The DOHC was available in South Africa until 2000).
I have searched the posts database, but have not found anything exactly like this, so here goes (I hope I get all the terminology right):
I have an infuriating vibration on my Pajero that manifests itself as a powerful drone at certain road speeds. It is related to road speed only and not engine speed and is most pronounced at around 50 mph and 60 mph. I bought the car in about August of 2004 and became aware of the vibration soon afterwards (when I had sorted some other things out and had learned the car's sounds to a certain extent).
The vibration can be replicated by lifting the rear wheels off the ground, engaging drive (2H on the transfer case, off course) and spinning the rear wheels up to road speed. The vibration occurs at exactly the same speeds (on the speedometer) as on the road.
I have done the following to try to locate root cause of the problem:
1. Had propshaft balanced (No real improvement)
2. Renewed universal joints (No real improvement)
3. Swapped wheels with my mates Pajero (No difference)
4. Had rear diff reconditioned (Cured whine, not vibration)
5. Fitted propshaft from another Pajero ( Vibration cured!! )
6. Had my propshaft rebalanced 4 times! (Vibe still there)
7. Had propshaft retubed (Vibe still there)
The somewhat haphazard process that I followed seems to indicate clearly that the propshaft is the culprit. As I see it the propshaft can generate the vibration due to bad universals or being off balance. The universals are brand new and are dead smooth and free, which made me assume that the propshaft was not balanced properly. This made me take the car back again and again to the propshaft service centre that did the balancing originally (I live in a somewhat remote little town in the part of South Africa known as Zululand and these guys are the only ones that I know of that can do high speed propshaft balancing).
The second to last time the shaft was balanced, I had the propshaft re-tubed to try to eliminate possible out-of-of-center positioning of the universal yokes.
The last time I witnessed every step of the balancing process and insisted on the balancing machine's adapter flange being trued up and the balancing being done at approximately 2500 rpm and double checked at 1500 rpm.
I will welcome any and all suggestions of possible cures or causes...
Kind regards
Gerrit
