Diff backlash with Truetrac

[Romulus]

Anyone with a truetrac fitted to their M86 diff experiencing excessive backlash? I've measured approximately 10 deg of backlash in the driveshafts left to right on both sides. Its not the CW&P back lash, that's been measured and in spec. Another observation is the driveshafts move up and down around 2-3mm when installed. I'm wondering if the truetrac is shagged. Hit and miss with these units, they're great for dealing with power but NVH is questionable IMO.

[MR_FG_09]

Yeah ive got a wavetrac in mine & it is quite clunky on the low speed on off throttle I can't confirm specifics on exact measurements but on wot it's awesome

[FrogXA]

I've got a Wavetrac in my BF XR8 and it's quiet as, wouldn't even know it's there to be honest. Agree though that at wot it is awesome.

[MR_FG_09]

Yeah I can't confirm 100% as I had a IMS twin bush hat fitted at the same time which definately makes the rear end more solid so it's hard to eliminate as the wavetrac & dss cv's went in at the same time

[Tom Tucker]

My trutrack has bulk backlash. Also IMS diff hat

[MR_FG_09]

Yeah ive learned to live with it I guess on the street as I do abit of happy laps roll racing style events where the full wot power down is awesome & tracks nice & straight plus the odd launch from the lights in Mexico

[FrogXA]

I've just gone from the CAT600 bushes to the IMS diff hat and still don't hear the Wavetrac at all. The whole diff is actually quieter with the IMS compared to the CAT bushes. I don't have the cv's though.

Check what type of oil they put in your diff also as the Wavetracs and Truetracs don't like slippery LSD type friction modifiers. I've got Penrite 80/90 mineral oil in mine and just change it more often.

[k31th]

of course the IMS is quieter than CAT bushes, as the CAT bushes are basically the noisiest mofos you can fit into that position ahha

[MR_FG_09]

I'm running Nulon 80w 140 Full synthetic as per Ray at Western suburbs diffs & gearbox's instructions in Brisbane as he gives the wavetrac his lifetime warranty

[FrogXA]

Nothing wrong with that, that's what I used to use for years but it wasn't the full synthetic. I used the mineral. I bought my Wavetrac from Ray as well and at the time (about 2015) he recommended a Penrite Limslip 140 LSD oil but when I did a bit of research, it had the friction modifiers in it so I decided to go with the Nulon 80w 140 based on what I had read on the American Wavetrac site.

 

I emailed the Australian Wavetrac distributor recently about what the best oil to use would be when I got the IMS kit installed and I just got a short reply with a link to the American website that I had looked at in 2015 when I bought the Wavetrac. All the oils they recommend are a bit hard to find at most local Australian parts stores.

 

Anyway, the performance/ tuning shop who installed the IMS kit for me said mineral oil was still the way to go and they do a lot of diff work so I went with their Penrite 80/90 recommendation.

[Romulus]

I had the right shaft replaced as the outer boot was leaking but the new shaft slops around in the diff like a wooden spoon in a bowl of porridge. I'll source a set of low k used territory shafts and fit them. I read to use a straight 140w mineral oil. Any oil used should be a mineral based on and rated at least 80-90w/140 with no friction modifiers. At some point the truetrac will have to come out and get binned (or sell on fleabay) and replaced with a new unit. But that's a $2.5k job that can wait for a later date.

 

Thanks for the feedback.