Keep breaking 3rd gear

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0ld school

0ld school

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I have broke 3 transmissions in 2 years. They are 18 spline 833 4speeds. It is always the 3rd gear, on the countershaft. It usually does not hurt the 3rd drive gear. This last time it did thou. They are all in street cars, making about 720 hp/660 tq. I don't speed shift, or have sticky tires. It always happens when it hooks in 3rd gear.

I know everybody is going to say get a Lenco, but I cant cut the cars. Is there anything I can do to help? Would the gear oil matter? I use 80/90 gear oil now. Is there anything you can do to the gears to strengthen them? I will be buying another countershaft, and drive gear tomorrow. Can you send them out for treatment? This is getting expensive, and the counter shafts are getting harder to find.

Lastly, I see they make a Chinese countershaft frown anybody have any luck with them? Harder to find originals anymore.....
 
Thats a little much for a 833 i would think, i wonder if the 5 speed trans that bolt in place would be any stronger

Short comings of the original chrysler overdrive. Inherently weak due to the undercut mainshaft in the 3rd gear and 3-4 synchronizer area


[ame]https://www.passonperformance.com/images/stories/passon_documents/Passon_5-Speed_Flyer_2010-11-18.pdf[/ame]
 
Agreed. Although I personally think its too much for street, i respect him and his car, if 700 is good for him on the street then more piwer to him, ill never down anyone for having more powa lol. Im not sure if there are many was to beef up a 833 especially if you already have the 18 spline. Passion performance also offers a hemi overdrive kit but not sure if it will make any improvements
 
I think I'm going to go with an American powertrain kit. they say no cutting to install. it will be a tko 600 tremec 5 speed. I can also up-grade the trans to a 950 ftlb rating. they can ship this kit in 2 weeks. if this kit works well, I will replace all the others as well.

anybody with any experience with this kit?
 
SuperStock said:
Where at the countershaft did it broke? At center?

Whats about the clustergear?
Click to expand...

third gear on the countershaft and the drive gear also. third is in the center of the main shaft and the counter shaft. i'm told they are pulling apart under power and breaking the teeth....
 

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The clustergear have only 2 pairs of bearing at each end; at the center is bearing-spacer (red arrow). If clustergear (housing) or countershaft broke, you can strengthen it by remove the bearing-spacer and add roller-bearing instead. I have not yet done it, nor heard anyone done it, just a thought.

However, from your picture, not the clutergear's housing broke but the cluster's gear itself. I have no idea how to strengthen it.

Btw, I love 720 HP :burnout: .What motor is it?
 
Since the cluster-gear is only supported on the outer ends...............I'm having trouble accepting the bending countershaft theory. Nor can I imagine that big meaty clustergear itself deflecting. If it was cluster-pin related I would expect 2nd to pop first; that gear is further up the cluster from the back and closer to the center, and since it has fewer teeth, they would be more heavily loaded.
What I can imagine is the mainshaft nose moving up and away, carrying that front bearing with it. There's just not enough support there in those few needle rollers.But what do I know!
I would be looking for a better front bearing, perhaps with more-balls or bigger balls,or something.

Now, I'm no engineer,and this is purely speculation on my part.
 
You need to call Jamie Passon and ask him for advice.
 
the 3rd gear in a mopar trans is the weak link. if you're lifting off throttle and then punching power back on, its taking hell of a beating!!! also clutch probably doesn't slip to absorb some of the power?? we use a soft loc it will slip and absorb the power, without breaking parts. might try a jerico trans, the gears are straight cut and very big. I think clutch needs to be looked at also .just food for thought.
 
a few years ago, I had a friend ran a 18 spline mopar trans behind his 500 " mopar. he broke 3 rd gear a lot. he did his burnouts in 3 rd gear. also had bronze puck clutch disc and lots of pressure. mccandless told him he had wrong setup. way too much clutch, and doing burnouts in 3 rd gear was causing his breakage.
 
No disrespect to Jamie Passon but I'd call Brewers and/ or Liberty. They seem more race oriented which is what original post was about.
 
SuperStock said:



The clustergear have only 2 pairs of bearing at each end; at the center is bearing-spacer (red arrow). If clustergear (housing) or countershaft broke, you can strengthen it by remove the bearing-spacer and add roller-bearing instead. I have not yet done it, nor heard anyone done it, just a thought.

However, from your picture, not the clutergear's housing broke but the cluster's gear itself. I have no idea how to strengthen it.

Btw, I love 720 HP :burnout: .What motor is it?
Click to expand...

it is a 500" motor......
 
Looks like perfacar gave you the answer in posts 14 and 15. Not sure you like the answer. But it is the correct answer.

Don't do burnouts in 3rd gear. Use a sintered iron clutch set up. Parts will stop breaking when the clutch is right.
 
I had a car do this a while back. We were not fixing the trans but just installing other transmmisions. Not 18 spline but not that HP either. And it was always Third gear.

What we found was the bell housing was not indexed to the crank properly. Since then we always index the crank to the bell and found many to be out. Even stock bells when moved to a different block.

If you **** the input it will change the mesh of the gears to tight or loose. Most good bells when purchace have weld on alighnment pin washers for this reason. Buy a magnetic dial indicator and check this first. They make eccentric dowl pins with slots to turn for adjustment. But when using them every time you take the bell off of the motor it has to be reindexed when installed. A large hole on bell and a weld on thick Bushing/washers are the way to go with a steel bell.

Standard bells also flex with that much HP. Blow proof steel with a mid plate is the best. Steel mounts also help. Properly installed and reamed bushing also. Steve
 
I have the fix for this problem coming soon! I will post pics, maybe this week. stay tuned!
 
Oldmanmopar said:
I had a car do this a while back. We were not fixing the trans but just installing other transmmisions. Not 18 spline but not that HP either. And it was always Third gear.

What we found was the bell housing was not indexed to the crank properly. Since then we always index the crank to the bell and found many to be out. Even stock bells when moved to a different block.

If you **** the input it will change the mesh of the gears to tight or loose. Most good bells when purchace have weld on alighnment pin washers for this reason. Buy a magnetic dial indicator and check this first. They make eccentric dowl pins with slots to turn for adjustment. But when using them every time you take the bell off of the motor it has to be reindexed when installed. A large hole on bell and a weld on thick Bushing/washers are the way to go with a steel bell.

Standard bells also flex with that much HP. Blow proof steel with a mid plate is the best. Steel mounts also help. Properly installed and reamed bushing also. Steve
Click to expand...

Its not this. I always set bellhousing run out. you are also correct, they are almost always way off! I also always use a Lakewood bellhousing. My problem is, to much power for the transmission. fix is on the way......
 
0ld school said:
Its not this. I always set bellhousing run out. you are also correct, they are almost always way off! I also always use a Lakewood bellhousing. My problem is, to much power for the transmission. fix is on the way......
Click to expand...


Unless you bought a sintered iron clutch, you have not found the fix yet.
 
yellow rose said:
Unless you bought a sintered iron clutch, you have not found the fix yet.
Click to expand...

The clutch has nothing to do with it. Every time it has broke the trans, the clutch was engaged. Foot nowhere near the pedal. When I roll hard in third gear, that's when it would break. Clutch engaged, hooking under power. The trans is just to weak. If it keep breaking when I dumped the clutch, or shifting, then yes maybe the clutch......

I have found the fix. I will post pics shortly....
 
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