| Author | Message | ||
     Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 111 Registered: 9-2013 |
Good ol' TH400 leaks fluid front & back, started small, but now to the tune of 2 small puddles of Dinosaur's finest Dex II at each stop longer than an hour. So I decided to remove Mr Incontinent and give him a new set of pampers:new seals, new steels, new frictions and fore/aft endplay according to factory-new specs. On top of that, I will install a TransGo shift kit (with soft shift setting, please). Gearbox has ''only'' 90k miles on the clock, but aside from the leaks, I'm not happy with the - sometimes - hard 1-2 shift. Playing a bit with a new, adjustable, vacuum modulator brought no improvement. My lift, where it is placed in the garage, can lift the car about 4 feet off the ground, which I judged sufficient for this project, but I'd need to sacrifice transmission jack accessibility. I'll show you how I worked around that issue. Other essential tools for this job is a set of swivel tools. They are essential in accessing the 6 gearbox and 3 torque converter bolts. Space is too small for a normal socket plus universal joint adapter. Lying under the car, I found out that some part of the exhaust needed to be removed to allow the gearbox to drop. I found that task surprisingly easy, no rust (I have the stainless exhaust), no dust, straightforward undoing of 4 bolts. A kid could have done that! Then, some of the parkbrake linkage had to be unbolted & put out of the way. Same for the gear selector motor. Again, straightforward unbolting. After that, the 3 driveshaft bolts had to be undone but boy, did they fight me, look on the picture how long a leverage was needed to finally make turn those nuts! The bolts on any car would have snapped faced to the torque I had to apply, but this is a Rolls Royce and all 3 survived my attack. Next were the bell housing bolts: I build a very long extension rod with SnapOn's finest 5/8 swivel socket at one end. This enabled me to undo the 2 top bell housing bolts in total comfort. Those 2 top bolts, I was told, were the hardest to reach, but I got them out in a matter of minutes! I think the SZ Corniche has more spare room than the 4 door variant. By then, my gearbox was hanging only on the remaining 4 bolts, so I thought that some support from below would be in order, and for that purpose, I used our family safe again. Readers of my 'oilpan removal thread' will instantly recognise my 2 hotel-style safe deposit boxes. What a useful companion to have in the workshop! But wait, wasn’t there something else connecting the gearbox to the car? Blimey, yes, the torque converter bolts! They are a nightmare to remove, I was told, but here’s my recipe for undoing them with no sweat and no swearing. I got all 3 out in less than 20 minutes. First, you need to identify where they are. For that, look at the torque converter (looking along the gearbox towards front of the car). You’ll see 3 – what I call – ‘’connecting bridges’’. Each bridge has one bolt behind, by which the flyheel bolts to the torque converter. Those bolts need to be undone from the front. they bolt to the flex plate, and I discovered one ''tunnel'' through which I can access them with another construction of extension rods and swivel tool that the end. I lifted the engine some 3 inches (need to undo all 3 of your engine mounts), then, either with the starter motor or with a screwdriver inserted in that slot specifically cut into the lower part of the flywheel housing, pry with a large, flat screwdriver onto the teeth of the flywheel until the ‘’connecting bridge’’ lines up in such a position as to access it from the other side, i.e. front of the car. I discovered a ‘’tunnel’’ big enough to insert my extension construction with a swivel socket that the end (will post the size later, forgot it). You can see on one of the pictures that found this tunnel by looking over the right end of the steering rack while having my left ear close to the front right brake disk. Finally, I undid the 4 lower bellhousing bolts. They are the easy ones. Last but not least, the whole gearbox still sits onto 2 guidance nipples to facilitate re-insertion, meaning that it needs to be pried off before it can be lowered. In my case the car was lifted and I was able to roll the gearbox away on the little trolley which I put under the supporting safe. All in all, it was just over 5h of work, It was mostly fluent work, undoing the propshaft was the main hick-up, I did not expect to cogitate a solution with such a huge lever and I am under the impression that reinstallation will go quicker. But first, I'll do a complete overhaul together with TransGo shift kit installation. JP DAF-10195               | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 112 Registered: 9-2013 |
the comments to my photos seem to got lost (((( | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1633 Registered: 6-2009 |
JP, There are no "comments to the photos" if what you're talking about is what you write between the curly braces of the image command. That's used as alternate text when an image won't load or by accessibility software for a description of the image. If you want actual visible comments you need to put them as their own lines above and/or below the photo in question. I tend to put these in using the bold formatting command (see the Formatting page) either above or below each photo to separate that text from my own commentary in a post. For example: Orchid Cactus Photo:  Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 938 Registered: 5-2012 |
Hi JP Nice job and thanks for sharing it. Have you a more distant pic to show the lifts you use. They appear to be scissor/hydraulic. Geoff | ||
| David Gore Moderator Username: david_gore Post Number: 1731 Registered: 4-2003 |
Hi JP, Congratulations on getting the hardest part over and done with successfully. Looking ahead, I found using 2 guide pins made by cutting the heads off two suitable length bolts and cutting a slot for a screwdriver where the head used to be facilitated reinstalling the transmission as it ensured quick and easy alignment with the bell housing. Fit the other bolts and nip up to take the weight off the guide pins then remove them using a screwdriver and replace the bolts. I used a B & M overhaul kit but kept the shift modification to give better clutch plate service life - the changes were perceptible under hard acceleration but if I wanted to "waft drive" passengers to impress them with the traditional R-R ride quality, it was simple matter of "feathering" the accelerator when the gear change was about to occur and the resulting change was barely noticeable. Takes a little practice to get it right but easy afterwards. | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 113 Registered: 9-2013 |
David, I read about the guide pins idea but found that the 2 pins on the casting were sufficient, but I was probably very lucky to get it in on the first attempt. | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 114 Registered: 9-2013 |
Geoff, The lift is a Nussbaum Sprinter 3000. http://www.nussbaum-usa.com/po...lio_item/sprinter-2/ Its german-made, not cheap at 3k-something. You can buy cheaper Chinese ones working of the same principle...but I did want to buy a lift only once. You must put some foam or rubber bricks between the lift's surface and the car's sills. I don't regret that purchase, I can do all the work on this and other cars. It will lift long-base SZ cars as well, and even my Merc GL. | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 115 Registered: 9-2013 |
Brian, Can't edit my post anymore in order to add descriptions to my pics. In short: 1st pic, shows the leverage arm that was needed to undo the bolts on the front driveshaft hardy disk. 2nd: I have 2 hotel-type safes which are super-practical almost every day. The wheels had to be prevented from spinning as I was turning the bolts with my huge lever arm. Park brake was not sufficient. The other pics are self-explanatory. The pic with the screwdriver tip shows how I turned the engine in order to align the torque converter bolts so that I can get access to them. | ||
| Lluís Gimeno-Fabra Grand Master Username: lluís Post Number: 399 Registered: 8-2007 |
Testomony of faith: I have been there, in his garage and I have seen it. He is really dismantling that poor old gearbox :-) Lovely... good luck. | ||
| Jean-Pierre 'JP' Hilbert Prolific User Username: jphilbert Post Number: 118 Registered: 9-2013 |
Here're my findings during de-gutting of the TH400:  Pic 1 shows the converter with some fresh fluid and some older one. I would not brush my teeth with that. This shows that there is not much circulation between gearbox (fresh) and converter (dead-end) fluid. As there is no drain plug on the converter, it seems the only methods to drain the converter fluid is to remove the converter and suck it out (need to remove the gearbox for that), or to drill a hole into the converter while still installed. Any of those solutions are suboptimal, but hey, the engineers designed this into the system, so I assume that not-so-fresh fluid has strictly no detrimental effect on the operation of the torque converter.  Pic 2 shows the flex plate in place after gearbox removal. Caution must be exercised to install the converter in the same position after gearbox overhaul!  Pic 3: One should measure the input shaft endplay right after gearbox removal. This enables you to select the new ''selective thrust washer'' according to your previous endplay. There exist 7 different-thickness selective thrust washers. Any overhaul kit will contain all of those.  Pic 4: no special slide hammer needed to remove the front pump. Simply use a rubber hammer and massage the pump out by hitting the thicker, less protruding shaft. Pic 5: trophy of that evening: front pump with forward clutch attached. The forward clutch came out together with the pump because it was still ''hanging'' on the bushing, which shows that the bushing clearance was still very, very good. Nevertheless, I elected to change all the bushings for education and for good measure.  Pic 6: always measure how far out things are sticking in that gearbox, or how far in they are located. This enables simple verification upon assembly that all items are seated correctly.  Pic 7: Now, if you venture into TH400 overhaul, you will be faced with much new terminology such as front pump (it's called that way even though there is actually NO rear pump), forward clutch, direct clutch, intermediate clutch, center support, reaction carrier, output carrier, output shaft, valve body, front & rear servo aso. Pic 7 shows the orientation plan which was stapled to my workbench. |
