Mo Murphy Posted June 22, 2015 Share Posted June 22, 2015 I'd like to cool the oil in my gearbox. Whilst away recently in high temperatures and long climbs it got fearfully hot. Has anyone here fitted oil cooling to their LT77 gearbox ? What are your experiences of installing and running such a set up. With the greatest respect to those who like to try to help, I'm looking for actual experiences rather than what you've read somewhere else ? Cheers Mo Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted June 22, 2015 Share Posted June 22, 2015 I was of the impression it's not easily done. The main reason I've fitted a Stumpy R380 to my 110. However I will be following this thread with interest. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 22, 2015 Share Posted June 22, 2015 I'd invest a couple of quid in some temperature-indicating labels, stick one on the box and see how hot it's really getting. Much over 50deg is too hot to hold your hand against but is nowhere near the limits of the gearbox oil's comfort zone - overcooling it could be worse than letting it run at 100deg+ 1 Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted June 22, 2015 Author Share Posted June 22, 2015 An interesting point fridge. What is a safe temperature for atf to get up to ? Mo Quote Link to comment Share on other sites More sharing options...
reb78 Posted June 22, 2015 Share Posted June 22, 2015 There is an adaptor housing for the LT77 I think, that will allow you to run an oil cooler. I was under the impression that the points were there on the rear housing of all LT77 boxes, but they weren't drilled/tapped to accept the fittings on many. See this thread post 9 for info on the cooler and the rest of the thread for other ideas: http://forums.lr4x4.com/index.php?showtopic=48184 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 22, 2015 Share Posted June 22, 2015 An interesting point fridge. What is a safe temperature for atf to get up to ? Mo Not sure about safe but normal working range extends well over 100degC. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted June 22, 2015 Share Posted June 22, 2015 ATF oil temp chart: http://www.digi-panel.com/trannyoil.htm Stickers available from Ashcroft. 1 Quote Link to comment Share on other sites More sharing options...
Ex Member Posted June 22, 2015 Share Posted June 22, 2015 Discos and RRs in hot climates had oil coolers on the LT77 from the factory. I thought that on a Defender it hit the tunnel. Quote Link to comment Share on other sites More sharing options...
DavidW Posted June 23, 2015 Share Posted June 23, 2015 I had a disco v8 lt77 rebuilt to defender spec at Ashcroft and wanted to keep the oil cooler kit seeing as I already had it. They said couldn't do it with the defender rear end. Quote Link to comment Share on other sites More sharing options...
pat_pending Posted June 23, 2015 Share Posted June 23, 2015 I had a disco v8 lt77 rebuilt to defender spec at Ashcroft and wanted to keep the oil cooler kit seeing as I already had it. They said couldn't do it with the defender rear end. Curious, as I'm sure I've seen coolers on 77s in military defenders. I checked my parts catalogue and it shows an oil cooler take off for a Defender 77 box. Quote Link to comment Share on other sites More sharing options...
DavidW Posted June 23, 2015 Share Posted June 23, 2015 Interesting, the plate looks quite similar to the disco part I had (unfortunately no longer) too. I was told they weren't really necessary, but you may have found otherwise. I think the temperature sticker idea is a good one. Quote Link to comment Share on other sites More sharing options...
pat_pending Posted June 23, 2015 Share Posted June 23, 2015 It shows it's possible, requires the correct tail housing though. Easiest way to go would be find an ex mil' box with all the correct bits already on. Mo, when I worked at A L/R main dealer I rebuilt dozens of lt 77s, all of them had suffered overheating. I think the cause was the mainshaft and layshaft clearances being too tight, I set them up with an extra few thou' and had no problems. They do get hot anyway and it would be a good idea to see if you have a problem first. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted June 23, 2015 Author Share Posted June 23, 2015 Thanks for your help chaps. I'll do as fridge and pat suggest and try the stickers although I'm far from the hot sun and steep mountain climbs now ? Mo Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 23, 2015 Share Posted June 23, 2015 I rebuilt dozens of lt 77s, all of them had suffered overheating.I think the cause was the mainshaft and layshaft clearances being too tight, I set them up with an extra few thou' and had no problems. I do wonder if slightly cooler oil would make any significant difference to a very localised hotspot like that? Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted June 23, 2015 Share Posted June 23, 2015 Did you get any issues with difficulty shifting etc. Mo during the heat? Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted June 23, 2015 Author Share Posted June 23, 2015 None James. Quote Link to comment Share on other sites More sharing options...
aigeas Posted January 14, 2017 Share Posted January 14, 2017 Hello. I would like to ask if there a kit for cooling the LT77 gearbox? I live in Greece where temperatures get quiet high in summer. I think it would be a good upgrade along with a temperature sensor-monitor connected to the gearbox. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted January 14, 2017 Share Posted January 14, 2017 (edited) V8 Discoverys had cooling. My understanding is that it won't fit in a Defender due to clearance issues at the gearbox. It could probably be done if you did not mind modifying the left side of the gearbox tunnel and seatbox. Might be difficult in left hand drive, but right hand drive would probably work. See item 18. http://www.allbrit.de/UNI.cfm?PAGE=803110&SPRACHE=EN http://www.allbrit.de/UNI.cfm?PAGE=803307&SPRACHE=EN Edited January 14, 2017 by Red90 Quote Link to comment Share on other sites More sharing options...
honitonhobbit Posted January 17, 2017 Share Posted January 17, 2017 Moseph I found that cooling the T box helped to cool the main box - I used the Rocky Mountain finned extension (and would do so again) I also used exhaust wrap along the section that runs close to the gearbox And thirdly I popped into Merlin Motorsport and bought a Red Line version of ATF that is super-duper high temp All worked well in temps of 45plus up and down mountains towing a 2 tonne trailer Although, its worth pointing out, my mate in his RRC doing the same route had no issues with his box and that was so hot it was shimmering in the heat - he was running standard Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 17, 2017 Author Share Posted January 17, 2017 Indeed Dave, I put Redline in after that trip. It was great last year, with no problems in the heat. I have found however that on frosty mornings with Redline, gear changes are reluctant until the oil warms up. I assume it doesn't like the cold. Mo Quote Link to comment Share on other sites More sharing options...
honitonhobbit Posted January 17, 2017 Share Posted January 17, 2017 I had the same issue with a recon LT77 from Ashcroft's - used a fully synth oil from the start. Great 10 months of the year; two months of the year was a nightmare for the first few miles. I used to start it, put the T box in neutral, put the gear box in 4th and go inside for breakfast. 10 minutes of that and it was fine Worth having a chat with Shabs at Syncro Gearboxes Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 17, 2017 Share Posted January 17, 2017 But did your box actually get too hot Mo? Oil's optimum working temperature can be over 100deg easily. I still say whack a temperature label on the side of the box & see what you get before you spend a load of time & money adding a new point of failure to your vehicle Quote Link to comment Share on other sites More sharing options...
Ex Member Posted January 17, 2017 Share Posted January 17, 2017 4 hours ago, Mo Murphy said: Indeed Dave, I put Redline in after that trip. It was great last year, with no problems in the heat. I have found however that on frosty mornings with Redline, gear changes are reluctant until the oil warms up. I assume it doesn't like the cold. I don't have any problems with it and I assume it gets a lot colder here. We were having highs of -20 C last week and commuted with the 90. Parked outside all day. No problems shifting right away. You are using MTL? Quote Link to comment Share on other sites More sharing options...
honitonhobbit Posted January 17, 2017 Share Posted January 17, 2017 JU, where did you acquire those remarkable stickers? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 17, 2017 Share Posted January 17, 2017 Lots here, guess it is where JU got them from too, or one of the other very similar places: http://uk.rs-online.com/web/c/automation-control-gear/sensors-transducers/temperature-sensitive-labels/ Quote Link to comment Share on other sites More sharing options...
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