eplummer

Sorry, I know the title is misleading and the truck is not shifting into neutral. But its newest problem is that it no longer shifts into 2nd, it just "freewheels". I.e., when it would normally shift into 2nd, the engine revs and the driveline stops spinning. The pinion and spur gears still spin madly, but until the engine revs slow down, the truck just sits there. And then you hear a "dink" noise and it's back in 1st and back to normal driving. The drive cups on the diffs are tight. I started to take apart the "external shift unit" to examine the one-way bearing and it looks clean and functions well (by hand). If the one-way bearing was malfunctioning, what would be the symptoms? It seems to me it would "slip" in 1st gear. I couldn't take the shifting clutch apart because I can't get the bearing inside the 39 tooth spur gear to slide off the shaft. Any ideas? Thanks!

BTW, it was shifting normally up until this problem started. And now it does this freewheeling every time it tries to shift into 2nd.

eplummer

Update... I was able to remove the bearing from the spur gear shaft and inspected the external shift unit clutches and everything looked ok. I am stumped as to what would cause this behavior!?!? I will disassemble the transmission next. The Genesis shifting and transmission units seem to be heavy duty, well built units, but I am trying to understand the engineering behind the doubled pinions/doubled spur gears. Since the pinions are fixed together and spin together, why not just have one pinion/spur at each shift unit?

The Real Dogman

You do have just one pinion at each shift. The small pinion is your first gear, the larger pinion is your second gear and third gear is inside the tranny. It sounds the one way bearing(Drawn Cup Roller Clutch) inside the tranny may have malfunctioned or is malfunctioning..

eplummer

I definitely need to study up on my gearing basics!

CEN Racing

What it sounds like, is your center outdrives (set screws) are loose. In the front and rear of your truck, there are 2.5mm set screws that hold the GS093 (rear) center outdrives to the MX037 bevel pinion gear.


If these screw become loose you will experience "free wheeling" as you stated. Check both the front and rear set screws that hold the center drive shafts to the MX037 bevel pinion.

Tighten them with lock tite so they do not come loose.

CEN Racing

GS043 for the front (center) and GS092 outdrive for the rear (center).

Set screw uses a 2.5mm hex and is 5mm x 5mm

eplummer

This behavior has replaced the shift to 2nd, and only occurs at that point. I can drive around in first all day with no slippage. I can hold the truck in place and force it to spin the tires under load and there is no slipping until the instant it shifts into 2nd. If the outdrives were loose, I would think it would always slip, especially after a tank or two.

CEN Racing

Then the only other possibility is the one-way bearing in your 2nd speed is not operating properly and is slipping.

CEN Racing

If your Truck is less than 60 days old contact our Customer Service dept and they will be happy to help you out with a solution.

Thanks.

eplummer

It's not within warranty, so I'll continue trying to fix it. This article was helpful (even though many of the graphics wouldn't load): http://www.rctek.com/transmission/in...ny_design.html. And another: http://www.rctek.com/info_bearings_one_way.html

.46NitroAddict

Ok eplummer,
If I understand your problems' description & subsequent descriptive responses correctly, I think your problem is in your 2nd gear clutch. Once you read the following dribble, you may see why I think it is so! I agree with you on the out drives, If your truck spins all wheels when against your foot!

Sorry for how long winded this is going to be, but this is how I understand the shift from 1st to second operates. I will use the part #'s from the Genesis LE manual, cause that's what I have & may avoid some confusion. All directions are view from the rear of the truck looking forward. Anyway here goes.....

When your motor rpm increases from an idle in a clockwise direction, to a point that your engine clutch shoes (GS003) fly outwards engaging with your Clutch bell (GS079), causing both your 1st gear pinion 17T (GS089) & 2nd Gear 21T (GS090) to also spin, at the same rpm, in a clockwise direction. This in turn spins both of the 1st & 2nd mating spur gears. [scratching your head yet? I was for a while until I sussed this out - I thought how can both sets of gears spin when they are different ratios].
Well, as the 1st gear pinion 17T (GS089) turns clockwise it spins its mating spur gear 43T (GS087) anticlockwise, this gear is mounted on a 1-way bearing hub (GS047) {locked when spun anticlockwise}, this drives the shift hub (GS055) that in turn spins the 3 speed transmission main input shaft anticlockwise via the hubs pin (GS061). Since the 2nd Gear pinion turns its mating spur gear (GS088) that is mounted on a clutch bell (GS056) & since this is currently disengaged [I will come to this later] it does nothing - it is just spins in neutral for the moment. So to summarise, the 1st gear pinion spins clockwise, this turns the 1st gear spur anticlockwise, causing the 1-way bearing to drive the transmissions' main input shaft anticlockwise. 2nd gear turns but provides no drive, because the clutch is disengaged!
As engine rpm increase , so too does the rpm of the 1st speed pinion & spur gears. This also cause the rotation of the shift hub (GS055) & its 2nd gear clutch shoes to also increase. When the rpm of these clutch shoes is fast enough the centrifugal force on them is such that they overpower their 2 outside springs & fly outwards engaging with the 2nd Speed clutch bell (GS056).
It is at this point that the drive is throught the 2nd pinion & spur gear. Since the 2nd gear spur is also turning anticlockwise & it is mated to the shift hub (GS055) via the clutch shoes, its' rpm is now greater than that produced by the 1st gear spur, thus defeating the 1st speed spur 1-way bearing. {when the 1-way is turned clockwise in relation to its center shaft, it freewheels}. Thus the transmissions main input shaft is now spun at a higher rpm in a anticlockwise direction by the 2nd speed gears & 2nd speed clutch. 1st gear is now in neutral due to the 1-way bearing.
When engine rpm drop to a point that the 2nd speed clutch shoes disengage, the 1st speed 1-way then locks up taking up the drive dities. 2nd gear, is now in neutral again.

If this makes sence to you, & you say that your truck will run all day in 1st & even do burnouts with all wheels, but stops when 2nd gear engages. Then your problem must be either your 2nd speed clutch not engaging correctly (check the center ballbearing adjustments - very critical otherwise the hub will just spin inside the clutch shoes & not force the shoes out to engage) or the 2nd speed spur gear is spinning on the clutch bell - unlikely since it is sort of keyed, but check it anyway!
If by some off chance the 2nd speed clutch shoes' 2 center ball bearings are both adjusted correctly, it may be possible that your 2nd speed is engaging, & it is you 3rd speed that is causing your problem. If this is the case then the same principle will still apply. Obviously for 3rd gear to be the problem you would have to be going damn fast.

As for the correct adjustment, of your 2nd speed clutch shoes' center ball bearings taken from my last post [link=http://www.cenracing.com/phpBB2/viewtopic.php?p=2164&sid=bd41468fc4ec35b8748a91608570953e#2164]here[/link] I realise this quote is about 3rd gear, but the center ball bearing adjustment is still the same! It is also a very good idea, to use a loctite thread locker on these center bal bearing grubscrews - so the blighters don't vibrate loose, & stuff up your adjustments!

I hope this sorts out your problem, .46NitroAddict [>:]

The Real Dogman

Wow nitro, you ok buddy?? That looked like it hurt just a bit....Great job!! That pretty much sums it up, Especially the part about third gear one way not functioning properly as a result of second engaging, they are linked.


Good Luck and have fun!!

eplummer

Nitro, thanks for taking the time to write all this up! I think this will help many people, including myself. I spent much of yesterday thinking about how the shift unit functions and realized my misunderstanding was thinking that the spur gears are locked together, which I realize now (of course) they are not! Everything on the external shift unit was set just right, and shifting to second worked perfectly up until the moment this problem occurred. So like you said, I started thinking about the internal shift unit. I was one of those that never could get it to shift to 3rd, so a few months back I took apart the tranny and tried a suggestion that was posted on CEN's forum, which was to shim the shoes apart with washers. I followed the manual (which matches your directions) to tighten the set screws. Still it never shifted to 3rd, but it has been ok in 1st and 2nd for a gallon of fuel. So... last night, when I peeked through the tranny access hole and used a screwdriver to check the internal clutch shoes spring tension, sure enough the clutch shoes were so loose you could swivel the shoes about 30 degrees without the bell moving. So I started thinking that all the screws (including the set screws) loosened a bit and when 2nd engages, 3rd is also trying to engage (or maybe 3rd is engaging first) and the hub is simply spinning inside the shoes. But this still wouldn't freewheel the drivetrain, because the hub and shaft would still be spinning via the larger spur gear on the internal shift unit. There must be something else inside the tranny that is disengaging when the shift to 3rd happens. Unfortunately, I won't be able to disassemble the tranny for a few days, but I am anxious to solve this problem!

.46NitroAddict

Hey The Real Dogman,
Thanks. Yeah, it was like 3 hours past my usual bedtime, so it was kinda hard to get it out! But, I think I got across what I wanted.


eplummer, I hope this helped your understanding of how the shift unit works. I was like you for a while until I pulled it all apart & started turning stuff!

Keen to see what you find,
.46NitroAddict [>:]

eplummer

An update... I took the transmission apart, and at first I didn't see anything unusual, broken, etc. As I was washing the internal one-way bearing, one of the little "leaf springs" that keep the rollers in place (see http://www.rctek.com/info_bearings_one_way.html) fell out. Further inspection showed that all of the rollers were loose in the bearing, which was very different from the similar one-way bearing used in the external shift unit (all of its rollers were firmly held in place). Still, the one-way action worked fine when I tried as hard as I could by hand to get it to slip. I put it all back together and it worked fine (no free-wheeling) for about half a tank and then started doing the same thing as before. I tightened down both shift units so they couldn't shift and was able to run another couple tanks through in 1st gear only with no free-wheeling. My theory is that the internal bearing (which is obviously damaged) has a "breaking" point now, and as soon as the shift to 2nd happens, that point is reached, and it freewheels until it slows enough to grip again.

.46NitroAddict

Hi eplummer,

Sounds like you have solved the problem. A slipping 3rd gear unit, 1-way bearing.

To prove it, have you locked up only the 3rd gear clutch? Since doing only this, will isolate its associated 1-way bearing. Allowing you to test 1st & 2nd gears without the suspect 3rd gear shift units' 1-way bearing influencing the result. Obviously your gearing is going to be way different to normal - as you know, much taller!

I realise you said, you locked the 2nd & 3rd gear clutches together, & all worked fine, but what happened when you locked 1 of them at a time? Thus isolating each 1-way individually!

Regards, .46NitroAddict [>:]

The Real Dogman

What was it I said the problem was in post #3. Somebody needs to start listening to me.....I feel so neglected, nobody loves me!!!!

Glad you found the problem. You need to change that part!!! I think you can change the "Drawn Cup Roller Clutch" one way bearing, look for the number on the end of the roller clutch and tell us what it says or better yet take a picture and post it. I can tell you how to change it for about $10


Let us know!!

.46NitroAddict

Hi
Congratulations TRD, yet again you were on the money....Don't dispair we listen.....!!!!!

At least after all this, eplummer now has a fix for his problem, ... and a better understanding of how his transmission & clutches, etc. all work!!

Win, Win,

Regards, .46NitroAddict [>:]

madbeast302

three years later I'm trying to help my buddy and all the answers are right HERE!!

.46NitroAddict

Hey madbeast302,

No worries - wicked little beasts aren't they! Especially once you get them sussed!!

Regards, .46NitroAddict [>:]