Rotella T4

[Guest]

Anyone else have problems with this oil? After I've changed my oil with it I've had a hard time shifting. The gears are clunky and it never seemed to clear up not even after a 100 miles or so. I found a bottle of some highmileage oil treatment stop leak/seal rejuvenator (figured it couldn't hurt the old dinosaur seals plus clutch plates are easy enough to come by although it hasn't affected the clutch) it's loaded with ZDDP, added a touch of that and now it's smooth as butter again like it should be. Should I be moving on up to the T6 as I'd rather not have to add anything to my oil? I refuse to pay $15 a quart for the motorcycle oil so if that's your suggestion mosey on...I also added the stop leak stuff to my leaking final drive at 1 part product to 4 parts gear oil and it also stopped the intermittent high speed leaking. I can say the stuff works for sure but would rather not use it if I didn't have to.

If there's another diesel oil suitable and within the same price range please let me know.

The stop leak oil treatment I'm speaking of. It's thick and sticky like honey but has quieted down valve train noise quite a bit since using it and also stopped gasket weeping too.

[Nessism]

If STP helps then I wouldn't be afraid of using it. ZDDP keeps going down with each new formulation it seems because it can damage catalytic converters. Maybe try the regular formula instead of the high mileage stuff which I think is even thicker than the standard stuff. Since you live in Texas where it's hot I don't see much of a problem. Thick oil is mostly a concern at low temperature so even if you add some of that stuff I doubt the overall viscosity will exceed 20W-45 which is fine.

[John Park]

The 550/650/650G gearboxes are derivatives of the 400/450 box which is, in my experience, more sensitive to the oil properties than the 5 speeds.

There is a move afoot to get the zinc out of diesel oils to protect the catalytic converters so the days of GS friendly cheap oil may be drawing toward a close. I never found Rotella to be all that wonderful in these boxes anyway, so went to synthetics about thirty years ago.

I see nothing wrong with adding some ZDDP if Shell decides to leave it out. There is a limit to how much you want to add as some sort of undesireable effects are supposed to happen if the levels get too high.

My theory - and that's all it is - is that the shift forks on the 'small' box have a different geometry on the shift drum making them more prone to cocking and dragging. The good part of that is that you know when the oil is wrong or shot by the gearbox action.

And before I mosey on..... yes, $15 oil will probably fix it. But you probably knew that already or you wouldn't have warned everybody including yourself.

[Gorminrider]

Anyone else have problems with this oil? After I've changed my oil with it I've had a hard time shifting. The gears are clunky and it never seemed to clear up not even after a 100 miles or so.

I've found many of the diesel oils crap out in the gearbox like you say, but for me they are ok for 600 miles or so and the crispiness then mostly shows up at slow speeds..stoplights etc... I also think I notice some variation in different diesel oils as to how long before the gearbox chops the oil up. It sounds like your issue is a bit more...still
T6 is no better, IMO, despite it being JASO compliant... But it is worth trying some of these and or knowing that these are at least ok if you have to get some oil at a roadside service station or small town.
Finally, I find this to be especially so on my Suzukis,( even more especially on the gsx 400 six speed ) versus the couple of Hondas I've had/have.
Others here seem pleased with T6 but not all...so I wonder How much this might be due to some previous abuse, country specific differences in oil composition, or actual gearbox difference I don't know.
I don't hear these complaints from the $15-a-quart people (american quart that is) but it is awfully dear to spend more on the oil than the motorcycle

[Nessism]

ZDDP in Rotella oils was in the 1600 PPM range two formulations back, then it went down to 1100, and now it's similar but with other changes. Most people using Rotella are happy enough but I wonder if the lastest formula has something else going on which affects gearboxes? Motorcycle oils have similar amounts of ZDDP with some exceptions, namely 20W-50 "V-Twin" oil typically up in the 1600 PPM range. This is expensive oil though. Rotella with STP may be the low cost answer if it works for you.

[Gorminrider]

I found a bottle of some highmileage oil treatment stop leak/seal rejuvenator (figured it couldn't hurt the old dinosaur seals plus clutch plates are easy enough to come by although it hasn't affected the clutch) it's loaded with ZDDP, added a touch of that and now it's smooth as butter again like it should be.

I think it's interesting that you found an additive helps!

[TxGSrider]

Many years ago when I was a kid (early 1980's), I had a T250 that shifted a little hard and made some noise. Since STP was the miracle fix-all, I poured some in the transmission (I don't recall how much), and low and behold, it quieted it right down and it shifted easier... for a few minutes. Then the clutch started slip so bad that it wouldn't hardly move. So I pulled the plates out and cleaned them off with gasoline (or something), filled it with regular oil and the clutch was ok and the noises and hard shifting came back.

[Wingsconsin]

ZDDP Plus

https://zddplus.com/zddplus-oil-addi...IaAkytEALw_wcB

[gsrick]

I've been using T6 for about 6 years now and haven't noticed any issues.

[Skinner]

I used T4 on my old GS650GL and never experienced any problems at all. Now I'm using it on my 750 Katana and am having issues with a "sticky clutch" when the bike is cold. After it warms up for a minute the problem goes away. I'm attributing this to the T4's 15W40 viscosity - it's perhaps just too thick when cold. I bought a jug of T6 for the next oil change so I'll see if it makes a difference.

[John Park]

Many years ago when I was a kid (early 1980's), I had a T250 that shifted a little hard and made some noise. Since STP was the miracle fix-all, I poured some in the transmission (I don't recall how much), and low and behold, it quieted it right down and it shifted easier... for a few minutes. Then the clutch started slip so bad that it wouldn't hardly move. So I pulled the plates out and cleaned them off with gasoline (or something), filled it with regular oil and the clutch was ok and the noises and hard shifting came back.

I had a T250 as well. I don't think they changed the gearbox more than they had to when they made the 400 twin. The one I had was also clunky until I put some synthetic in; the price didn't matter as there wasn't much in there and you only changed it about as often as the piston rings. Different $$ situation when you have three quarts and a motor to fry it and crap in it.

The 650G - I've never had one - uses one of the gearsets of the 6 speed to drive the shaft bevel gears, and that pair has a reputation for failing [??] from having to work all the time. Given that, I'd be pretty careful about oil type and freshness, considering the cost and complication of fixing it. But fresh dino oil with enough ZDDP should be as good as any for gear longevity.

The big 5 spd gearbox doesn't seem to be anywhere near as fussy as the 6 speed about oil.

[Nessism]

FYI, lubing the shift shaft where it goes though the engine cover can help with shift smoothness. Grease is best but you have to remove the cover (obviously.)

Interestly, on my KZ750 with the shift lever attached directly to the shift shaft, the shift quality was okay but far from ideal. After installing some rearset GPz footpegs and articulated shift linkage the shift quality improved noticeably. Apparently the KZ shift lever was leading to a sideways bending moment which created binding when shifting, but the articulated linkage eliminated that; booting the lever resulted in pure rotational motion at the shift shaft and that greatly improved shift action. This taught me how critical it is to eliminate friction at the shift shaft (if possible.)

[leftlostcommonsense]

With the straight t4 I have nothing but trouble from the moment I do an oil change with it. It stays clunky no matter what with the T4 unless I add the zddp then all is well. Without the additive I have to put quite a bit of force to shift no matter which way I go or the temperature of the engine, and also have a hard time finding neutral. I have hit a few false neutrals too whereas I can shift with ease and no problem whatsoever with the additive. It may be time to move on to one of those higher dollar oils as I don't like the idea of continuing to add an additive at every oil change. Either way, maybe this will help someone later on down the road with a clunky gearbox on the cheap lol.

[Nessism]

Have you tried reducing clutch cable freeplay? Maybe your clutch plates are warped?

[steve murdoch]

I've been using T6 for about 6 years now and haven't noticed any issues.

Ditto, only for 5 years.