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Date:         Tue, 5 Jan 2010 20:12:42 -0800
Reply-To:     Daryl Christensen <daryl@AATRANSAXLE.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Daryl Christensen <daryl@AATRANSAXLE.COM>
Subject:      Re: Now Vanagon TDi Transmission  Survival Strategy
Comments: To: frankgrun@AOL.COM
In-Reply-To:  <8CC5C94878B7D28-3CE8-10BF7@webmail-d072.sysops.aol.com>
Content-Type: text/plain; charset="UTF-8"

Well done Frank...Ya got my attention. The word of the day is Oiling Plates...They go both in the main case beside the ring gear and in the gear housing by 3rd/4th to redirect the splash oiling towards the pinion and M/S bearings to force feed any splash oil to where it will do some good. Designed, I assume, by the S.A. guys to gain an extra 80 Nm ( ? 75HP? ) of "safe" additional power according to the Euro guys I have talked to.

I agree that cooling is key and have no problem with an external cooler, but for most, its out of reach due to the fabrication necessary.

Using the proper tranny oil can make ALL the difference and is an easy "fix".. I suggest Swepco 201 or 203 racing oil for a TDi or a 3.3 SVX conversion. I have seen several rigs that were driven hard and put away wet that ruined the R&P's after less than 2 yrs. They were using a lighter gear oil (maybe even Redline) that didn't hold up to the stress and torque of the 200 + HP with these heavy rigs we drive. For those with stockish vans or very cold temps, Redline works just fine. Still change it every couple years though to be on the safe side..( or so as not to have to deal with the likes of me...)

During a rebuild, we constantly see looseness of components as the cases get tired. Bad bearings peen the magnesium alloy metal and cause the bores to expand. Rebushing cases and other parts also tightens up the tolerances and slop that wears gears and shafts. The closer to factory specs, the longer it will wear correctly and tolerate big horsey power... No personal experience with the Cryo or bead blasting stuff, so no help there. Tag your it Frank.. Daryl of AA Transaxle 425-788-4070 "On the cutting edge of Old technology"

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Frank Grunthaner Sent: Tuesday, January 05, 2010 7:08 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: Conversion? JETTA ENGINE?? Now Vanagon TDi Transmission Survival Strategy

Don,

Couldn't agree more with your comments. I have always viewed the SA drip plates as a stopgap or bandaid strategy. There are obviously some strength of materials issues. The use of different alloy materials in aftermarket gears; bead-blasting for stress relief and cryo treatments all serve to move the failure point to the next weakest component. For continuous use the real enemy is heat and cooling of the transmission lubricant is a definite solution, as I indicated in that lengthy post.

But a few more comments are possibly warranted. On the subject of bead blasting and stress relief. The actual mechanism (of the bead-blasting effect) includes a level of local surface annealing along with the generation of a whole collage of micro fissures or cracks. Seen on the microscopic scale, the net effect is to make the the top several hundred microns of the part into a poly crystalline matrix. Consequently there are no well defined macro stress lines to lead to simple fracture propagation. In essence, micro faults can open and close without opening a break all the way through the part cross-section. If cryo-treatment is done correctly, the part is first heated to a softening temperature, then quenched in liquid nitrogen. The net effect is to amorphize the surface region. This essentially randomizes the metal unit cell and makes the surface harder than any crystalline equivalent. Done incorrectly, the cryo-treatment can give very large stresses that can give a shattered part when subjected to use stress.

I'm almost convinced that the design of the vanagon transmission with the 4.57 or 4.83 R&P, updated 3/4 slider and beadblasted 3/4 gearsets can handle the TDi torque load with temperature control. Start/stop stress is nicely handled by the 4 spyder gear mod to the differential carrier. The additional weak points of the pinion bearing and the needle bearings may well be adequate with thermally controlled lubrication. In my approach, I intend to pick up lubricant at the oil drain plug, draw it out and through an inline particle filter to the 12v gearpump, then send the liquid to the oil cooler (fan driven air-to-liquid) and then a return to the filler hole in the case. I'm using an Audi squirrel-cage injector cooling fan for moving air to the oil cooler (also taken from my collection of Audi 5000T parts). The oil filler hole is not angled perpendicular to the gear cluster, but rather is pointed towards the bellhousing at roughly 45˚ to the gear cluster. The clearance around the fill port is rather tight. Nonetheless, I'm wondering if a modest nozzle forming aperture directed back at the pinion needle bearing and 3/4 cluster area might not be advantageous? In other words, would a directed fluid jet increase the lubricity and fluid exchange in the gear cluster above and beyond the level achieved by the 30% level of gear immersion? I'm also wondering about the oil level in the case at speed. In other words, does the apparent oil level at the fill port decrease when the vehicle is at speed wrapping around the gear cluster. This is important for sizing the possible oil jet diameter and for determining the recirculation rate - while staying away from cavitation or aerosol formation.

Finally, the character of the lubricant could seriously help here. The new designer synthetic lubricants add several desirable properties to the problem. First, they can maintain a low and uniform viscosity over a very broad range of temperatures. Secondly, they conduct heat from metal interfaces much more effectively that the older petroleum formulations. This means lower gear surface temperatures and better heat transfer at the lube-to-metal-to-air interface in the oil cooler. Third, they wet the metal gear surface more effectively maintaining film adhesion under much higher contact pressures and shear forces. Lastly, the molecular film drag is considerably reduced as compared to traditional fluids. The LAT synthetic 75W140 synthetic racing gear oil seems to be the current latest word for high shock pulse loads in differentials. Yet, most manufacturers of synthetic racing gear oils do not recommend their use in VW transaxle--WHY?

Questions, questions! I had hoped to provoke a response and discussion with Daryll and/or other transmission professionals. Alistair recently brought to my attention this excellent website on a Syncro Project (http://vanagonsyncroproject-herman.blogspot.com/). Here Herman shows his transmission solution, but I'm reluctant to tear open the transmission again. Fascinating approaches! Excellent reading.

Frank Grunthaner

-----Original Message----- From: Don Hanson <dhanson928@gmail.com> To: TDI-conversion@yahoogroups.com Sent: Mon, Jan 4, 2010 7:11 am Subject: Re: [TDI-conversion] Re: Conversion? JETTA ENGINE?? Now Some TDi Comments (Shortened Version)

Scott, Frank Here are a couple of ideas on helping a tranny stay alive when you are feeding it big torque. Keeping the internal temp down seems critical. A positive flow transmission cooling system is beneficial. A good source for the components and plumbing parts to fabricate one might be here: http://www.batinc.net/porsche.htm Go back to the BAT homepage for a huge selection of hydraulic fittings, hoses, etc. No personal affiliation with BAT other than I used them when fabricating a system for my big torque stroker V8 Porsche racecar transmission. With some careful planning you'll be able to safely keep the operating temps of your trans axle within acceptable limits. I was told the repeated failures I saw, until I addressed the problem, were caused partially because, as the trans axle gained excessive heat, the internal tolerances changed, generating further heat ...creating a bad situation.. I say you must use "careful planning" for a tans axle cooling system..It should be designed and executed so that if any of the extra components (hoses, pumps, wiring, sensors, switches, etc) should fail, the transmission will revert to it's 'un-cooled' state, rather than become unlubricated.. I was able to configure the system on my 928 trans using the filler and drain openings. Seems like this might be a viable approach for most trannys and a way to work up a cooler system without extensive machine work on the transmission cases.. You might also, should you have your tranny apart, consider having the internals cryogenic-ally treated. I am told this is similar in results to bead blasting (it is supposed to reduce 'internal stress' in the part that is 'super-cooled') and the process is fairly rea$onable and quick. I was told all the NASCAR teams do this routinely, so on my final transmission ( before I ran out of spendable income and ceased racing my big sporty car) I had my internals cryogenic ally treated. With good cooling and perhaps that cryo-treatment, I was able to race a full season without another failure of my gears..Cryogenics might be BS, but the cost was comparatively little in my racing budget so I did it and I'd do it again for a high-torque application. Running a Vanagon at sustained higher speeds against a headwind/uphill or with a big load...in combo with extra power..it will create more heat in the gears...If and when the internals become excessively hot the various components expand, often at different rates, causing even more friction, which in turn causes even more heat...Better to spend a few hundred on keeping things cool, if you are running a power train that might push the design limits of your tranny. Don Hanson Mon, Jan 4, 2010 at 3:42 AM, Scott Greiner <greines@yahoo.com> wrote:

Frank, Thank you for your time and thorough details. If you are ever in the Phx, AZ area, let me know! Dinner and Drinks are on me. Scott Greiner Mesa, AZ 1982 Diesel Westy-With a 1997 Jetta AHU 1.9 TDI DZ Transaxle Re-Built with a 3rd 1.14, 4th .70 & a 4.57 R&P by AZTransaxles in Phx, AZ - Thanks Bill Engine Left Mount - "To clear the Turbo", Viton Fuel Line Kit & VS Sensor, etc from GreaseWorks- Thanks Justin; great website!! R&R of 1997 Jetta TDI Donor Car's Engine, ECU, Wire harness, intercooler, rebuilting the turbo, in to my 82 Diesel Westy- Thanks Paul my friend & neighbor. Exhaust System - Stock 1997 Jetta's Header pipe with 4" high flow muffler form local shop. Misc parts, thanks BAP, PartsPlace Inc., Carl's VW Speed Shop, Autohaus South Bend Clutch Inc - Thanks Andy for the 228mm Clutch Plate Air Cleaner - K&N from Pep-Boys Intercooler Piping Fabrication by my friend Mark-Thanks! Lots of help from the awesome members of this forum-Thanks! A whole lot of Vanagon Websites - Thanks for Shaing! My Cuzin Carl for giving me this broken down VW Vanagon. My Wife for putting up with me though all this. Thanks Margaret My friend Zac for starting me on Bio-Diesel. Adding a 1987 Vanagon Instrument Cluster "bought off E-Bay" for Cruise Control-Soon!

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