Rock Crawler gears in 75 Series

[Mr X]

SQ, or anyone running a 75 Series t/case,

I've got the Marks gears (-68% low / -8% high) in my diesel Bundy. I was just wondering if anyone else with these gears has that beautifully ear-splitting gear whine. I've had mine for 2-3 years & when they 1st went in, the t/case was pulled apart 3 times to check everything & Marks sent me a 2nd set (which were slightly better - but still heaps noisy).

Their explanation was along the lines of the manufacturing process being unable to get the tolerances to the same level as the original Toyota gears.

Does anyone else have this noise & have you done anything to reduce it?

Thanks,
X.

[humphey]

hi mate , i have a set in me shorty with a 75 series trans with marks gears yes they are a bit noisey but mine are not to bad , the worst noise is at 80/100 km but i just live with it .

[humphey]

put some lucus oil add in and that helped a bit .

[dumbdunce]

are they roller bearings for the output gears or the bushes? did you replace all the bearings etc through the whole transfer case? did you leave anything out? the thrust washer on the outer end of the idler shaft is pretty famous for getting left out of these transfer cases and they make some bad noises as the idler gear eats its way through the case.

did you properly clearance the case as per the instructions and make sure there was no potential for contact between the gears and the case - you need to make sure there is about 1mm clearance as under load the case does distort a bit and the gears move around a little bit.

even in stock form the landcruiser split transfer is never completely quiet even from new.

I have installed a couple of sets of those gears and found them not to be noticably much noisier than stock. sometimes with new gears it takes them a few hundred km to settle down a bit but they should be pretty good.

just turn the stereo up

and if you've still got your factory bundera transfer gears they will be worth something to someone with a 60 or 75 series, the 2.3:1 low range is a marked improvement over the 2:1 in the bigger cruisers.

[Mr X]

Thanks boys,
I was curious more than anything. I'm quite willing to put up with the noise for those insane ratios.

Dumbdunce, I had them installed by my regular 4WD workshop dudes & they pulled them out & checked everything after they were installed, & again a few hundred km's later. I've probably done 15-20k km on them now & the t/case was inspected again recently (unrelated issue) & there is no noticable wear. Thanks for the details - I'll check with the boys next time I'm there.

...Yeah, it took me about 3 days to buy some bigger speakers!!!!

My old FJ40 had a hideously noisy gearbox after a snatch strap/tree incident. I used to suffer from a bit of tinitus, which I put down to playing in a band & going to gigs. I sold the '40 & the ringing in the ears stopped!!!

[SQ]

Hey Mr X! I found when my gears were first put in, which was last September, they were really noisy. Now though, I hardly notice them. There's a bit of a whine above 80, but it's not annoying.

I've also got a Mate with a 60 Series with the same gears as mine and is finding that they arn't as noisy as they used to be as well.

You've probably already checked, but I found the gears sounded a bit quiter after I put the the gear stick boots down properly. It made a bit of a difference for me.

[madnavi]

How good are these on and offroad

[dumbdunce]

How good are these on and offroad

they are pretty awesome. you can drive slower, up steeper hills without stalling or slipping the clutch, you get thrown around less, less chance of vehicle damage, and less stress on other driveline components unless you really go gangbusters.

[sierrajim]

Try some nulon gear additive. Have used this in many makes of vehicle including the gearbox of an old 75 series ute that had a stuffed 5th gear, the noise almost dissapeared.

Can get it at Repco, Bursons etc.

[Mr X]

Thanks vitarajim, I tried the Nulon last oil change & it seemed to take the edge off the noise (or was it all in my head???). I might try a few different additives like the Lucas stuff humphey tried....or some fluffy floor mats.....or a 6.5 Chev & extractors......

Thanks for all the tips, lads.