rvwp Posted April 8, 2015 Report Share Posted April 8, 2015 Hi, My TR6 is suffering from the the dreaded transmission knock when cruising at say 30 mph in top. There isn't any diff noise or whine. By holding the diff input flange and turning a rear hub there is definite angular movement between the diff output and input shaft. Also there is some play in the drive shafts, but how much of this is splines or UJ's is difficult to assess. However the diff play is easier to feel. Question: How much angular play should be expected/acceptible. If less than I have what are the difficulties that may be encounterd in stripping and reshiming the diff to acceptable levels. I am a competant person with an engineering background and have rebuilt many engines and gearboxes but never a diff. If I have to have the diff out I would atomatically replace the drive shaft UJ's Appreciate any help/guidance. Thanks Rich Quote Link to post Share on other sites
ed_h Posted April 8, 2015 Report Share Posted April 8, 2015 The factory spec for backlash is 0.004-0.006", but it is measured at the crown wheel. Diving into a differential is doable, but not for the faint of heart: http://bullfire.net/TR6/TR6-38/TR6-38.html Ed Quote Link to post Share on other sites
Stag powered Posted April 8, 2015 Report Share Posted April 8, 2015 If it is an otherwise quiet diff, the problem with excessive backlash is often the bronze thrust washers under the little bevel gears inside the diff. Removing the diff is not particularly difficult, but make sure you mark the bearing caps so you don't mix them up. The workshop manuals say you need a case spreader to refit, but I have done several without, simply by placing the outer bearing races in position at an angle and tapping the whole assembly back into the diff casing using the wooden handle of a hammer. To remove the centre pin holding the gears, simply tap out the roll pin holding it in place, but IIRC the pin will only come out one way as the hole seems to be tapered, so if it doesn't shift, don't keep whacking it harder, try knocking it in the opposite direction. The thrust washers should have the thickness stamped on them, but this has normally worn away. The very centre doesn't wear so can be measured to give you the required thickness, sometimes a slightly thicker pair of washers can be fitted to account for wear in the thrusts under the gears on the output shafts. The diff in my TR originally came out of a Dolomite Sprint, I fitted new washers at the time, and again about 70,000 miles later. it has now done about 230,000 miles on its original bearings, and apart from oil seals and the two sets of thrust washers, it is still working well. Neil Quote Link to post Share on other sites
rvwp Posted April 9, 2015 Author Report Share Posted April 9, 2015 Hi Guys, Thanks for the insight to the wonders of the TR6 Diff, especially the link Ed, very informative. I feel very happy now to strip and rebuild the diff to reduce the backlash which is probably the main factor in my jerky transmission. Of course I will replace the UJ's in the drive shafts at the same time whilst they are out of the car. Now hopefully replacing these UJ's should be simple, or ?? Thanks Rich Quote Link to post Share on other sites
ed_h Posted April 9, 2015 Report Share Posted April 9, 2015 Simple? Yes. Without risk? Not exactly: http://bullfire.net/TR6/TR6-39/TR6-39.html Ed Quote Link to post Share on other sites
JJC Posted April 12, 2015 Report Share Posted April 12, 2015 The bull fire.net description of the diff rebuild is very impressive. The depressing part is replacing the oil seal in the inner side shaft. The one that connects to the half shaft. I'm just at the stage of separating the flange from the shaft. As the article says not easy. Anyone done it and got any tips? JJC Quote Link to post Share on other sites
Mark69 Posted April 12, 2015 Report Share Posted April 12, 2015 Ed's work is very impressive he came to my aid a while ago and have followed his work since. When I replaced the seals in my different I had my local engineering shop split mine cost me twenty quid Quote Link to post Share on other sites
Steves_TR6 Posted April 12, 2015 Report Share Posted April 12, 2015 The bull fire.net description of the diff rebuild is very impressive. The depressing part is replacing the oil seal in the inner side shaft. The one that connects to the half shaft. I'm just at the stage of separating the flange from the shaft. As the article says not easy. Anyone done it and got any tips? JJC I did this job last year, and worked out a nifty trick to separate the parts to get vat the seals. Bolt them back to back! Tighten the four bolts evenly and one of the two side will let go, then using sockets as spacers you can repeat to get the other one apart. Have a search on the forum as I posted pics previously. HTH Steve Quote Link to post Share on other sites
JJC Posted April 12, 2015 Report Share Posted April 12, 2015 If I knew how to search on the forum I'd probably be clever enough to split the flange from the shaft anyway. JJC Quote Link to post Share on other sites
JJC Posted April 12, 2015 Report Share Posted April 12, 2015 Bolt them back to back! HTH Steve When you say "bolt them back to back" what are "them"? Remember I'm not an engineer but I have managed to remove the inner shaft without damaging that lovely bearing. JJC Quote Link to post Share on other sites
rvwp Posted April 13, 2015 Author Report Share Posted April 13, 2015 Hi Guys, Can see how placing the flanges face to face and bolting through would work, but I'm guessing you were lucky Steve. I reckon after 40 years together plus separating the taper by just bolt pressure might not be enough? Has anybody used a company down south to rebuild their TR6 diff, importantly using quality bearings/seals, rather than rebuild at home. Hardy Engineering in Leatherhead Surrey who advertise in the practical Classics specialise in gearboxes and Diffs. By conversation they seem to know about TR6 Diffs and are quoting £300 +vat to rebuildwith new bearings/seals etc. Whilst clearly it can be done it seems fairly fraught with problems and am wondering if its worth it when taking into the cost of parts, bearings etc. Be interested to know members experiences. Regards Rich Quote Link to post Share on other sites
TriumphV8 Posted April 13, 2015 Report Share Posted April 13, 2015 Hi Rich, the diff relys much more than other parts on the quality how the work is done. In my opinion this is much more relevant than the parts itself which with no doubt despite that should be of acceptable quality. So you end up with diffs that show a limited mileage even on a poor performing US TR6 with carbs up to my 5 litre that runs for lots of years now without damage. Some years ago it got a QUAIFE LSD and meanwhile several times new sealing rings especially those at the stub axle that do not stand the extraordinary heat when driven hard on the highway. Expect 30 degrees plus driven speed in Km/h over a longer time > 170Km/h > 200 degrees oil! So if its the first diff I would give it to a well named specialist. Quote Link to post Share on other sites
stuart Posted April 13, 2015 Report Share Posted April 13, 2015 If I knew how to search on the forum I'd probably be clever enough to split the flange from the shaft anyway. JJC This is the thread you will need to read. http://www.tr-register.co.uk/forums/index.php?/topic/47989-tr4a-diff-output-seal/ Stuart. Quote Link to post Share on other sites
JJC Posted April 13, 2015 Report Share Posted April 13, 2015 Stuart Great thanks. Wish I could find threads like that! JJC Quote Link to post Share on other sites
Steves_TR6 Posted April 13, 2015 Report Share Posted April 13, 2015 Searching on this forum is an art, yet another that Stuart excels at ! Quote Link to post Share on other sites
stuart Posted April 13, 2015 Report Share Posted April 13, 2015 That wasnt too difficult, I knew it was your reply Steve so I just searched your content and found it that way. Stuart. Quote Link to post Share on other sites
Steves_TR6 Posted April 13, 2015 Report Share Posted April 13, 2015 That wasnt too difficult, I knew it was your reply Steve so I just searched your content and found it that way. Stuart. I wondered if Albert might have helped! Quote Link to post Share on other sites
JJC Posted April 13, 2015 Report Share Posted April 13, 2015 Steve - having just tried it and not got very far had a closer look at your picture. Looks as though you used bolts smaller than 5/16. I guess to get enough thread. The bolt head on larger bolts fouls the flange. I might try studding. The flanges do seem very tight. Did you hit it to get it to split? JJC Quote Link to post Share on other sites
JJC Posted April 20, 2015 Report Share Posted April 20, 2015 Well the bolting back to back worked a treat. So thanks for the tip Steve and thanks for finding it Stuart. What you didn't say was how impressive the shock is that you need to get the flange to let go. Fortunately I have an expert friend with a big hammer and drift and impressive accuracy with the hammer. The consensus from the experts round here (not me I just hold things and make the. Coffee) is that you need the shock so in a press it would be difficult to do because the support you'd need for the flange would be in the way. JJC Quote Link to post Share on other sites
Steves_TR6 Posted April 20, 2015 Report Share Posted April 20, 2015 Good work JJC Fwiw I didn't need to hit/shock mine, but the diff was rebuilt in the 1990s so only 20 years old really :-) Steve Quote Link to post Share on other sites
astontr6 Posted April 22, 2015 Report Share Posted April 22, 2015 Dear All, Parting the Diff Hub/Stub Axle Years ago the Triumph Garage near where I lived, used a Sykes Pickavant Hydraulic Hub Puller, 8 tons Pressure applied. The stub axle was held in a vice, the puller applied, an old bath towel put over the assembly and then the flange hit with a alum. drift and club hammer. There was always a large crack as the hub came off, as the hub had started to cold weld to the stub axle. This is the method that I have also always used. There has been no Triumph taper yet that has defeated my SP Hydraulic Puller!!! If you live near me I would do it for you? Bruce Quote Link to post Share on other sites
Nikos Posted September 1, 2020 Report Share Posted September 1, 2020 Hi everyone, I seem to have to an impaired crown and pinion in the 3.45:1 diff of my 1972 TR6. Replacing crown and pinion would be an option, however I am located in Athens and unfortunately there no TR6 diff specialists that could do the job on proper standard. It would be great to have any reference to diff specialists in the UK that are best placed to recondition my unit or exchange it with a properly reconditioned one. Thanks in advance Nikos Quote Link to post Share on other sites
cvtrian Posted September 1, 2020 Report Share Posted September 1, 2020 (edited) Nikos Pete cox sports cars - https://petecoxsportscars.co.uk/ should be able to help with parts and reconditioning in the UK, and Richard Crewe Read, on this forum, might be able to offer an exchange. Its a long way from Athens and they are heavy items..... https://www.tr-register.co.uk/classified/2446/TR56-345-TR4A-37-Ratio-Diffs-Fully-rebuilt-for-sale I see on the TR R website there is a Triumph Sports Club Greece - https://www.tr-register.co.uk/international-groups website www.triumph-club.gr based in Athens In Tr Action, TR Register Greece is listed as Yiorgos Karageorgos 148 Emm. Benaki Street, Athens, 11473 Good luck Ian Edited September 1, 2020 by cvtrian Quote Link to post Share on other sites
Openscape Posted September 1, 2020 Report Share Posted September 1, 2020 I wouldn't use Hardy Engineering, full of hype. They rebuilt my diff but after 500 miles it was whining again. I included a good quality original CW&P, which they said was good to use. They offered to look at it again but at my expense of courier costs, not to mention all the work to take out and replace. Be very careful who you use if farming out the work. Quote Link to post Share on other sites
RogerH Posted September 1, 2020 Report Share Posted September 1, 2020 Hi Nikos these people have had a couple of good recommendation on this forum - no bad ones. http://www.testransmissions.co.uk/tes-transmissions-contact-us-2008.html They are in Westbury Wiltshire UK. I have no connection with them. Quote Link to post Share on other sites
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