| Author | Message | |||
     Gordon Norris Prolific User Username: crewes_missile Post Number: 134 Registered: 2-2005 |
Not so long ago I thought my vacuum modulator had expired, but it turned out to be a cracked vacuum hose, and the modulator checked out OK. However, I priced a new one from Crewe (A$490 from the Sydney agents), and from Introcar (approx A$100, plus air shipping to Sydney approx $60 Total= $160) Now, one can walk into any auto parts store or speed shop and buy an adjustable vacuum modulator for any Turbo 400 for as little as A$25-$35! Not cheap chinese stuff either; "MADE IN USA" printed on them. (yeah, I know, shoddy yank stuff  ) I was wondering if anyone has any experience of using these generic adjustable units for future reference, including any warnings, advice, etc. Even the reputable name brand overhaul kits seem to include these same adjustable modulators. Crewepart $490, Generic adjustable $25-35...hmmm...decisions, decisions...  GN. | |||
| Dick Wood New User Username: woody Post Number: 5 Registered: 3-2005 |
don't you just love the fact that since we drive a Rolls we can just throw money away for parts with the Rolls name on them. I needed a thermostat. Gas station price about $5 for any American part. Rolls part shipped from England $25. My local Rolls mechanic $200. wish I were rich. I have no problem substituting parts. | |||
| Gordon Norris Prolific User Username: crewes_missile Post Number: 136 Registered: 2-2005 |
Woody, I don't mind supporting the factory parts in the hope that supply will continue IF they ARE unique/factory parts. However, when dealing with things like the transmission parts which are GM anyway, I object to the huge mark-up. Same for a multitude of other parts from outside suppliers. Hence the stalwart efforts of many, especially Larry Halpert, to find substitutes. I often joke their parts pricing is derived by "think of a reasonable price and then multiply by 10". GN. | |||
| Robert Wort Grand Master Username: robert_wort Post Number: 183 Registered: 12-2004 |
Hi Gordon, I once worked it out as a multiplication of 13. WOW! Does this mean that there's a sale on? I'd better not tell my wife. She might just buy everything.  | |||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 694 Registered: 4-2003 |
A word of warning on modulators. When I had the transmission fully overhauled (due only to leaks at 185,000 miles) on the T-Series 10 years ago by Autotorque in Philip ACT, and excellent outfit by the way, they fitted new everything including a modulator, a generic type. The transmission seemed perfect at first, so I drove to Sydney. I realised soon that, when hot, the transmission was so slushy that I drove it back from Sydney to Canberra with the vacuum hose disconnected and blocked, and in second gear as I was worried that it was slipping. The cure was a new genuine modulator after some fiddling around with other new non-Crewe-boxed ones with no improvement. We toyed with the idea of an adjustable modulator, but quite correctly the shop decided to fit a new Crewe one as the transmission had their 3 year warranty. Mick at Autotorque heeded my concerns over possible slipping, and removed and stripped the transmission again to be sure that no damage had been done. I have no idea why this was the case, nor do Autotorque. Problem solved, no more questions. Just a warning. Also, 20,000-series onwards Turbos have a different modulator from the common one on Shadows and other SZs. RT. | |||
| David Gore Moderator Username: david_gore Post Number: 433 Registered: 4-2003 |
In all matters relating to the Turbo 400 transmission; I turn to the following reference which is a "must have" for anyone wishing to know more about or work on these transmissions:  I have extracted the relevant information on fixed/adjustable modulators and their testing in the following file - sorry for the page misalignment as getting the book on the scanner was not easy!!
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| Gordon Norris Prolific User Username: crewes_missile Post Number: 137 Registered: 2-2005 |
Thanks David, The spine of this book is looking at me from my reference bookshelf as I type! You are right. It is a great book that de-mystifies TH400 autos and is oh-so-easy to read. Richard's tale is interesting though and that is one of the reasons I started the thread, because even the book says the adjustable modulators cover 95% of applications...wouldn't it be just typical if RR/B's were in the other 5%!! All such tales and warnings are useful and cautionary..BUT, I note Richard didn't actually try an adjustable one, so maybe someone else has, or knows of a technician that has (either successfully or not). Fore-warned is fore-armed... And yes Richard, the standard factory modulator is colour-coded blue the turbo one is colour-coded brown. GN. | |||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 695 Registered: 4-2003 |
Thanks, David. Ron Sessions' book is indeed the bible. I bought mine from Motorbooks, Military Road, Neutral Bay if someone needs one. Gordon, I would happily try an adjustable modulator myself. If a shop does the job for you as in my case back then, you give them the choice and respect the warranty. At the time, having driven 800km in a state of anxiety, it was just a relief to have the problem settled with a fixed unit. One thing at a time... RT. | |||
| Gordon Norris Prolific User Username: crewes_missile Post Number: 138 Registered: 2-2005 |
Richard, Don't get me wrong. What you did and your repairer did was absolutely the wise decision at the time. I'm just interested to know if anyone has tried an adjustable modulator, and did it do the trick? Like I noted above, there is a huge price differential...but it's not a bargain if it doesn't do the job. Maybe the "king of conversions" , Patrick Lockyer has had some experience on this front. And isn't it amazing how some books just end up being THE definitive book in their field...and we've all got a copy.. GN. |
Modulators