Dogleg weakness?

[EricJB]

I seen it posted many times that the dogleg 5 speed is weak.

Where is its weakness?

 

Has anyone blown one up from abuse ( hard launch), and what broke?

[Jayden71]

I'm interested in this too as I'm gonna throw one in mah 521 here soon.

But I don't drive mine very hard or very often

[EricJB]

I have run them for almost 20 years, and have never had a failure. I just mated an LZ23 to one, and am concerned that it might be too much. So I'm contemplating swapping the slicks out for street tires to keep it together. But if 1st gear is strong and 5th gear is weak, I will leave it alone.

 

If nowone has blown one up, I guess I will be the lab rat.

[HRH]

They are weak. My dogleg in my 510 was rebuilt three years ago, roughly 15,000 miles or so on the 510 in that time, estimated. I have (had) a high strung L20B with 11.5 :1 compression. I'm also hard on transmissions. Anyway, only three years of autocross and fun on the street, I have bearing howl like you wouldn't believe. Still works, but since I had to yank the motor, I'm using this opportunity to swap trannies and go with a 280zx 5 speed. Lots stronger for continued abuse.

[wayno]

I have went through about 4 of them, not a good transmission for a truck.

Only time I had to be towed home was because of a dogleg locking up, my datsuns always made it home somehow except for that day, won't put another one in a truck again, I just build a shortshaft 5 speed out of a 85/86 nissan 720 tranny anymore for my L block engines, the parts are out there to put one together, you just have to find them.

Why do you want one anyway, there getting hard to find and are expensive.

[EricJB]

It's already in the truck, and I have a spare. The plan is to swap it out for a Z box, or even a jatco auto from an 81 turbe zx.

 

Just need to make it live for awhile.

[EricJB]

They are weak. My dogleg in my 510 was rebuilt three years ago, roughly 15,000 miles or so on the 510 in that time, estimated. I have (had) a high strung L20B with 11.5 :1 compression. I'm also hard on transmissions. Anyway, only three years of autocross and fun on the street, I have bearing howl like you wouldn't believe. Still works, but since I had to yank the motor, I'm using this opportunity to swap trannies and go with a 280zx 5 speed. Lots stronger for continued abuse.

I had one that howled pretty bad in 5th. If that is the weak spot than I have no worries, as I never use it.

[wayno]

Except for the one locking up when I let the clutch out in first, and yes I did dump the clutch, I was in a hurry, I was making a U turn and was holding up a car, needless to say they had to go around me.

It locked up tight, the clutch had to be in for the engine to run, but it would roll, because I could push it around even though the front of the tranny was locked up, the shifter was jammed also.

Most of the time 5th gear would start howling real bad in my dogleg trannys, as I haul a lot of weight, and I tow a trailer, 5th gear doesn't like constant pressure, it's not made for it, it's a small car transmission, and they don't haul much or tow things.

I went through one about every year and a half, I got tired of changing them out, so I built a one out of a 85 shortshaft 5 speed.

http://community.ratsun.net/topic/28473-how-to-put-together-a-shortshaft-5-speed-for-a-l20b/page__view__findpost__p__422824__hl__wayno__fromsearch__1

[kelowg]

blown up two of them, broke 2nd gear countershft tooth and syncro's wear out btween 1st and second, suspect the bearings are most likely weak point

[Logical1]

I own 4 doglegs that I have swapped in & out several 510's I love the pattern and have no problems other than sychro wear. My current DD is a L18 with dual SU's and a subi lsd with 7" tires, I dump the clutch on her and shift like animal - Still running strong. I am very interested to find out the major weak points though as I would like to re-build one and improve anything I can.

[datzenmike]

It's all relative. I generally say they are weak because I expect that the person contemplating an install on his 510 is going to 'drive' it and performance will be uppermost in his mind at least 50% or more of the time. If it was going to be driven like the family mini van then it would last forever. On top of this EVERYONE drives differently and what some would call 'spirited driving' others would call 'going shopping', and not all motors are stock power. So there are several levels of possible abuse to consider here... different driving styles and different power levels.

 

Very generally the FS5W63A dogleg is more than adequate for a stock L16 or 18 but only just adequate for L20B and larger. Because of this I would recomend a 620 truck or a 280z or zx 5speed because they were intended for six cylinder or truck abuse to begin with. Yes you have to shorten the driveshaft but this is way cheaper in the long run than rebuilding the dogleg or converting to the 71B later.

 

I'm not saying they won't last, that depends on driving style, performance and the age and wear on the dogleg you get, but if you want performance you'd remove the L16 and install an L20B or larger motor. So it makes sense that when you upgrade from your four speed to a five speed you would get something more 'robust'. Another thing to consider is that the dogleg is somewhat rare and has only one other range of gear choices, those from the '80-'81 A10 with the Z20 motor. The 71B is very common (280z, 280zx, Maxima and 620 trucks with L bolt pattern, and in non L bolt pattern on 720 trucks and the S110 and S12 200sx) and comes in at least 3 ranges of 1-4 gears and several overdrive 5th gears..

 

The dogleg is a fine five speed, make no mistake, but is not as strong as the 71B.

 

 

Tips for extending the life of any 5 speed:

 

Change the oil every 3-5 years or 30K miles.

Use only GL-4 80W90 oil or equivelent that says 'yellow metal compatible'

NEVER use 5th gear to accelerate to pass on the highway, climp steep hils or if towing or heavily loaded. Downshift to 4th.

Inspect for leaks visually at least every 3 months and check oil level every 6 months.

Disconnect the driveshaft if towing by the front for more than 30 miles.

[hang_510]

i abuse dog legged trannys and never had one die.

[datzenmike]

You probably looked after it.

[EricJB]

So dumping the clutch with the loud pedal on the floor, rev limiter at 6600. Should we start a pool on how long it lasts?

[HRH]

About 3 years I reckon. They're tough, just not that tough. And $350 for three years isn't a bad return on investment, but I rather like when they don't break regardless of abuse.

[wayno]

It may last as long as you own/drag the truck, you never get into 5th anyway, so personally I don't see the point in even using it.

Except for the one that locked up, all my doglegs started howling real bad in 5th, and the second gear syncros would go bad, as I shift very fast between these gears when under load going up hill, but I have the same issue with the 720 transmission 2nd gear syncros also, eventually they are unable to take the continued abuse, but I have no issues with 5th anymore, and I am always under load in 5th on the hiway, hail LZ23.

 

Any transmission you use is going to get abused, between the locked rearend, and the highly modified engine, none of them will last forever.

Have your ever fast shifted between first and second on a dogleg tranny, you know that the reverse gear is not locked out on a dogleg, at least the ones I had were not, I could go from 1st to reverse without any restrictions.

 

I think how you actually use your truck, it isn't going to matter what tranny you use, you just need the gearing that works best for you.

[EricJB]

The only reason I'm using it is because it's been in the truck for a looong time. It was my DD, farm truck, sold, bought back, street rod, and now drag project. I have replaced every moving part on the truck, but never got to the gearbox.

All the changes I made this year has left me with no time, money, or energy to swap it out. So I am trying to get an idea of how much shock it will take, and then give it 10% less.

Eventualy it will probably get an auto. It would be nice to have a couple of doglegs to sell, to pay for the auto.

[hang_510]

So dumping the clutch with the loud pedal on the floor, rev limiter at 6600. Should we start a pool on how long it lasts?

it will be the 3rd thing that breaks, not the first.

[wayno]

The only reason I'm using it is because it's been in the truck for a looong time. It was my DD, farm truck, sold, bought back, street rod, and now drag project. I have replaced every moving part on the truck, but never got to the gearbox.

All the changes I made this year has left me with no time, money, or energy to swap it out. So I am trying to get an idea of how much shock it will take, and then give it 10% less.

Eventualy it will probably get an auto. It would be nice to have a couple of doglegs to sell, to pay for the auto.

 

 

I wouldn't worry about it, just go as fast as you can, fact is, I am the only one I know that has locked one up, and all the other dogleg issues I have heard about, or had happen to me, have to do with 5th gear howling.

[datzenmike]

Draging is all about getting into and through the gears as fast as possible and the dogleg does not lend itself to this at all. 1st to 2nd should be quick and precise and any time lost here is ten times harder to gain back at the top end of the strip. Just sayin'..

[EricJB]

Draging is all about getting into and through the gears as fast as possible and the dogleg does not lend itself to this at all. 1st to 2nd should be quick and precise and any time lost here is ten times harder to gain back at the top end of the strip. Just sayin'..

No doubt. That 1st to 2nd is a bitch. The loose shift pattern doesn't help either.

[wayno]

If your shifter is loose, then it's likely the shifter bushings, take the shifter out and inspect them, that's an easy fix.

[datzenmike]

This is a very common bushing used from at least '74 on the B210/260z/280z/280zx/620/Maxima/200sx and more. The number is 32855-H1010 about $4.

[ddrum]

My transmission on my L16 is approximately 26 inches long and my shifting pattern is

 

1 3 5

2 4 R

 

and ive heard doglegs have

 

R 2 4

1 3 5

 

so are there different shift patterns for doglegs?

[datzenmike]

No. It's name derives from the shift from 1st forward, sideways to the right, and forward into 2nd. This would somewhat resemble a dogs hind leg.

 

The only 26" H pattern L series 5 speed would be have to be an FS5W71B from a later 720 truck. There were 26" and 31.5 " Z series 5 speeds available in them. Someone has put the front case from a 620 or z/zx onto it and converted it for use on an L series motor. Nice going, they are a nice strong transmission for a 510..