SteveA Posted January 5, 2010 Share Posted January 5, 2010 As part of a 200tdi conversion we are moving over the Discovery crown wheel and pinions from the donor vehicle and fitting them into series diffs, but setting the pinion heights looks like it could be a bit of a ball ache e.g. what height to set it at? and what tolerance should this measurement be to? Also, can anyone tell me what the difference is between rationalised and pre-rationalised differentials? we have pinion heights for both, but are unsure if either of these are relevant. Thanks Quote Link to comment Share on other sites More sharing options...
Gremlin Posted January 5, 2010 Share Posted January 5, 2010 Why?? when you could have bolted the whole disco diffs instead of the series diffs!! Its a straght swap! G Quote Link to comment Share on other sites More sharing options...
SteveA Posted January 5, 2010 Author Share Posted January 5, 2010 It'll be something to do with the air-locker rear diff, the number of splines on the rear half shafts and lack of oil level holes on the Disco diff I guess Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted January 5, 2010 Share Posted January 5, 2010 Steve don't know if this is of any help, but did what you could call the opposite. I mounted the housing off of TDI axle with a 24 spline airlock (RD128) into my series axle casing along with the series R&P. I just made a hole to fill in the oil using a nut and a bolt. as simple as that! Don't worry about the other nut it is for my airlock bulkhead thiny because I didn't have the right tap for the threads. Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted January 5, 2010 Share Posted January 5, 2010 Rationalised should be metric and pre rationalised will be imperial. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 5, 2010 Share Posted January 5, 2010 As part of a 200tdi conversion we are moving over the Discovery crown wheel and pinions from the donor vehicle and fitting them into series diffs, but setting the pinion heights looks like it could be a bit of a ball ache e.g. what height to set it at? and what tolerance should this measurement be to? Also, can anyone tell me what the difference is between rationalised and pre-rationalised differentials? we have pinion heights for both, but are unsure if either of these are relevant. Thanks On series diffs with 3"od carrier bearings the pinion height was 1.5" from the bottom of the bearing saddles, plus or minus the value etched into the pinion face.Later pinions were presumably produced more accurately and had a Zero etched on the face.for a height gauge I had a steel bar about 2" dia that I machined exactly 1.490" long that I sat on the pinion face.I had another straight ground steel bar that I would roll across the carrier bearing saddles, and if I could just get a .010" feeler gauge between the height gauge and the saddle bar the height was correct.Later metric carrier bearings are smaller in diameter, So I had a steel disc (can't remember the thickness )that I sat on the height gauge to make up the difference. Bill. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted January 5, 2010 Share Posted January 5, 2010 When fitting true trac replacement diffs into series axles one has to fit a spacer ring between the diff carier and the crown ring. Presumably this implies that the series crown is thinner than the newer crowns. Thus a reverse fitting would be difficult without machining either the carrier or the crown. I think. G. Quote Link to comment Share on other sites More sharing options...
DaveSIIA Posted January 6, 2010 Share Posted January 6, 2010 When fitting true trac replacement diffs into series axles one has to fit a spacer ring between the diff carier and the crown ring. Presumably this implies that the series crown is thinner than the newer crowns. Thus a reverse fitting would be difficult without machining either the carrier or the crown. I think. G. Could be that the pinion diameter is smaller on the Series to give the lower ratio. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 6, 2010 Share Posted January 6, 2010 When fitting true trac replacement diffs into series axles one has to fit a spacer ring between the diff carier and the crown ring. Presumably this implies that the series crown is thinner than the newer crowns. Thus a reverse fitting would be difficult without machining either the carrier or the crown. I think. G. The crownwheel mounting flange on the 3.54:1 carrier has a greater offset than the 4.7:1 carrier, hence the need to fit the spacer ring and possibly longer bolts when fitting 4.7:1 crownwheels to a 3.54:1 carrier. Presumably the market for 4.7 type Tru Tracs is too small to warrant making a special carrier for them. only concern I have with using a spacer ring is you lose the spigot diameter that locates the crownwheel concentric with the carrier an are just relying on the bolts to do so. Bill. Quote Link to comment Share on other sites More sharing options...
Daan Posted January 6, 2010 Share Posted January 6, 2010 I dont think you can fit 3.54 c+p onto a 4.7 carrier, because of the offset, like bill mentioned now being the wrong way. You would need a spacer with negative thickness, which hasn't been invented yet. Daan Quote Link to comment Share on other sites More sharing options...
Gazzar Posted January 7, 2010 Share Posted January 7, 2010 I dont think you can fit 3.54 c+p onto a 4.7 carrier, because of the offset, like bill mentioned now being the wrong way. You would need a spacer with negative thickness, which hasn't been invented yet. Daan I think that's what I was trying to say, but understandable! I always thought negative thickness meant it was time for..............BIG ANGLE GRINDER!!! G. ps - sorry about this 0-0 I'm feeling irreverent (or is it irreverant??). Quote Link to comment Share on other sites More sharing options...
Daan Posted January 7, 2010 Share Posted January 7, 2010 I think that's what I was trying to say, but understandable! I always thought negative thickness meant it was time for..............BIG ANGLE GRINDER!!! G. ps - sorry about this 0-0 I'm feeling irreverent (or is it irreverant??). Sorry, hadn't worked that out from your post, but anyway, we are saying the same thing. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted January 7, 2010 Share Posted January 7, 2010 Sorry, hadn't worked that out from your post, but anyway, we are saying the same thing. Don't you apologise for me being too dense to explain something! G. Quote Link to comment Share on other sites More sharing options...
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