When It Rains It Pours Clutch Slippage G56

[rsl0311usmc]

I wanna give a big thanks to toyota mdt for the input on oil and especially this pedal adjustment. Honestly I think you saved me from losing my mind LOL. So I adjusted the pedal further out above the brake pedal and wow what a difference. It still takes a little force in 1st and reverse but nothing like it was. I really appreciate it toyota mdt tech thanks for all your input.
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[toyota_mdt_tech]

Ok I got the doorman boot arriving today and still waiting on the delvac 50 oil.

So should I adjust the pedal in or out?

I got it about three quarters above the brake pedal.

I appreciate your help 1st and reverse are driving me nuts.

Not going into 1st or reverse is a tell tale sign of clutch just not quite fully releasing. So adjusting the pedal up a bit should do it. Wont take much and also make sure your pushing clutch all the way down, slide seat forward if needed and no balled up floor mats under depressed pedal.

Did they use hypoid gear lube, ie GL5? Its a no no, you must have GL4

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[toyota_mdt_tech]

I wanna give a big thanks to toyota mdt for the input on oil and especially this pedal adjustment. Honestly I think you saved me from losing my mind LOL. So I adjusted the pedal further out above the brake pedal and wow what a difference. It still takes a little force in 1st and reverse but nothing like it was. I really appreciate it toyota mdt tech thanks for all your input.
20221014_181020.jpg

You shouldnt have to force it, this will put a heavy load on your synchros (wear). Maybe adjust pedal just a little higher. Just make sure you have the free space, ie some movement before you feel clutch pressure, this way, you know clutch is fully engaged. Maybe the gear lube? The GL5 can create shifting issues, be nice to know what they used.

I just did all this, so its all very fresh in my mind, I did swap my ATF+4 long ago to my redline 75W90 GL4 years ago (full synthetic), including T case too.

Once you get adjustment dialed in, its golden for the life of the clutch.

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[toyota_mdt_tech]

I wanna give a big thanks to toyota mdt for the input on oil and especially this pedal adjustment.

Well, I want to give a thanks to rsl0311usmc, its obvious you have, or are still serving our country, so thank you for your service to our great country.

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[rsl0311usmc]

Well, I want to give a thanks to rsl0311usmc, its obvious you have, or are still serving our country, so thank you for your service to our great country.

Thanks man I appreciate everything. Not sure what fluid they used other than 75w 90 weight. I can't wait to get the mobil delvac sae 50 in there. I may at this point return it for the redline you told me about. But its going to be here soon. As for clutch pedal man, it was to the floor everytime before and it wouldn't go in. So I adjusted the clutch pedal about three quarters of an inch at the bottom of the clutch pedal above the top of the brake pedal if that makes sense. So far a big big difference thanks to you toyota md tech. Now I won't lie I push a little hard for first and reverse but nothing like I was before. Before I was literally trying to in a shift motion bang it into gear it was terrible and wouldn't go without like three slams forward. As far as the other gears go I noticed they shifted even better after the adjustment. I am not sure how far up on the clutch pedal versus the brake is considered to far. Thanks again everyone.

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[rsl0311usmc]

You shouldnt have to force it, this will put a heavy load on your synchros (wear). Maybe adjust pedal just a little higher. Just make sure you have the free space, ie some movement before you feel clutch pressure, this way, you know clutch is fully engaged. Maybe the gear lube? The GL5 can create shifting issues, be nice to know what they used.

I just did all this, so its all very fresh in my mind, I did swap my ATF+4 long ago to my redline 75W90 GL4 years ago (full synthetic), including T case too.

Once you get adjustment dialed in, its golden for the life of the clutch.

A part of me is wondering like your saying if it has anything to do with gl4 or gl5. I know gl4 is what's required but all I was told was 75w 90 gear oil. It's better after the pedal adjustment by far but the delvac 50 can't come soon enough just out of curiosity

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[toyota_mdt_tech]

A part of me is wondering like your saying if it has anything to do with gl4 or gl5. I know gl4 is what's required but all I was told was 75w 90 gear oil. It's better after the pedal adjustment by far but the delvac 50 can't come soon enough just out of curiosity

Trying to find articles on GL4 vs GL5, GL5 is corrosive to synchros and more of an extreme pressure lube for hypoids and can hinder synchro performance. Remember, a synchro is like a brake. As you slide the shifter from one gear to another, you apply pressure on the synchro (cone shape) which then using friction, gets the mating gear set rotating at the same speed and once the speed is matched, the hub slides over the mating spline to lock that gear to the shaft.

Our transmission are constant mesh design, meaning gears are always meshed already, we are just locking the gears to the shaft. That is done with the synchro and another cool device called an inertia lock. Synchro matches the speeds, inertia lock holds the gears in place. The inertia is what some call dog teeth, the same teeth are on the underside of the slider. Pointed tips, and the sides of the teeth narrows as you go to the base of the teeth. This narrowing is what holds the gear in place under a load. When you grind a gear on a full synchro transmission, you are clashing the dog teeth. There is a drive side and a coast side on these teeth. If you ever get a gear that pops out under load or decel, the teeth are narrower at the tip instead of the base one either coast or drive side, so under load, they push themselves apart. The dancing shifter during accel and decel is a sign dog teeth is going away.


Certainly GL5 temporarily isnt going to kill your transmission, but if it is GL5, over time, synchros will corrode (eats yellow metals) and the extra friction modifiers in GL5 impede the action of the synchros. Synchros rely on some friction, GL5 makes them slipperier hindering shifts.

OK, probably more info than you needed, but good info for other members.

My truck with my 75W90 GL4 is only clumsy cold shifting down into second which is my main start gear, I just come to full stop before shifting to second. Shifting up isnt an issue and in short order, all is good rest of the day, shifts fine after 20 minutes or so.

You installers said gear oil, that is a generic term for both hypoid and transmission oil, but to refine it more, hypoid or transmission oil. So its possible they did put in GL4 but you mentioned stink, that usually points to GL5

Here is a link, any generic search using GL4 VS GL5 should get you some more answers.

GL4 vs GL5

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[rsl0311usmc]

Trying to find articles on GL4 vs GL5, GL5 is corrosive to synchros and more of an extreme pressure lube for hypoids and can hinder synchro performance. Remember, a synchro is like a brake. As you slide the shifter from one gear to another, you apply pressure on the synchro (cone shape) which then using friction, gets the mating gear set rotating at the same speed and once the speed is matched, the hub slides over the mating spline to lock that gear to the shaft.

Our transmission are constant mesh design, meaning gears are always meshed already, we are just locking the gears to the shaft. That is done with the synchro and another cool device called an inertia lock. Synchro matches the speeds, inertia lock holds the gears in place. The inertia is what some call dog teeth, the same teeth are on the underside of the slider. Pointed tips, and the sides of the teeth narrows as you go to the base of the teeth. This narrowing is what holds the gear in place under a load. When you grind a gear on a full synchro transmission, you are clashing the dog teeth. There is a drive side and a coast side on these teeth. If you ever get a gear that pops out under load or decel, the teeth are narrower at the tip instead of the base one either coast or drive side, so under load, they push themselves apart. The dancing shifter during accel and decel is a sign dog teeth is going away.


Certainly GL5 temporarily isnt going to kill your transmission, but if it is GL5, over time, synchros will corrode (eats yellow metals) and the extra friction modifiers in GL5 impede the action of the synchros. Synchros rely on some friction, GL5 makes them slipperier hindering shifts.

OK, probably more info than you needed, but good info for other members.

My truck with my 75W90 GL4 is only clumsy cold shifting down into second which is my main start gear, I just come to full stop before shifting to second. Shifting up isnt an issue and in short order, all is good rest of the day, shifts fine after 20 minutes or so.

You installers said gear oil, that is a generic term for both hypoid and transmission oil, but to refine it more, hypoid or transmission oil. So its possible they did put in GL4 but you mentioned stink, that usually points to GL5

Here is a link, any generic search using GL4 VS GL5 should get you some more answers.

GL4 vs GL5

I appreciate all the information and help.

So today, I got impatient waiting for my Delvac SAE 50 and talked to an Amsoil guy thats local.

I saw that he had in stock 75w 90 MTG.

I was looking for redline like you were saying, but I would've had to order that also.

I noticed on the Amsoil it meets Mercedes-Benz specs for the G56.

He had only 6 quarts, so I grabbed them and got to thinking.

For the seventh quart, I have a bottle of Amsoil synchromesh for an NV3500 I have in a K1500.

So today I drained that junk GL5 out and mixed up the secret sauce LOL.

I also put a new boot on and forgot how much fun that was.

Then I drove her and instantly saw a shifting improvement by far.

It was literally almost perfect but still missing just one more thing.

Like you said toyota md tech I have to get the clutch pedal dialed in just right, so that's what I did.

I adjusted the pedal a tad higher because every time I did I noticed 1st and reverse seemed to get easier.

For this truck, it seems to like a higher clutch pedal.

Now I can get into first and reverse with just a sturn pull or push, nothing super crazy like before by any means.

To give a comparison 1st and reverse felt no different shifting when I had the stock one in.

As far as the rest of the gears and shifting, it's smooth as butter.

I am happy with this clutch now and really appreciate all the help, information, and tips.

It's alot of money to put out, and it's frustrating when you can't get it right.

Oh, btw no more smell in the cab either .

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