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Getrag strength. Im impressed. by Fierobsessed
Started on: 11-28-2004 05:45 PM
Replies: 25
Last post by: AaronZ34 on 12-02-2004 01:03 PM
Fierobsessed
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Report this Post11-28-2004 05:45 PM Click Here to See the Profile for FierobsessedSend a Private Message to FierobsessedDirect Link to This Post
I've been inside a Getrag, and many other transmissions from many vaious manufacturers including Mitsubishi and Honda. The Getrag, is BY FAR, the strongest FWD Manual transaxle I have ever seen, and the most durable. The one I opened was a 91 Quad 4 getrag. Heres why I feel it is one of the strongest/durable designs I've seen.
First of all, First gear is 3/4" thick. I have never seen a transmission with that strong of a gear.
The syncronisers are STEEL, the actual friction surface was Sintered Brass, witch is some tough stuff.
Getrag syncroniser detents (blockers) A whole heck of alot better then The Fiero Isuzu ring springs with the 3 blockers, or Honda's "just a ring" blocker. The getrag uses coil sprung, ball bearing detents to hold the blockers. These are the best because there are no real wear parts, and the blockers kinda follow to the engagment collar once its in gear, witch helps prevent the transmission from blowing out of gear. The engagment collar has an unequal Arrow for engament, It looks like a hole saw with backward teeth. What this means is it's designed to anticipate the next gear, but it also means that when the engagment is not complete, it Will blow the engagment ring off the gear, with much greater noise and force, but wears the transmission out much less then it sounds (or feels) like it does. Thats why a getrag grind is so loud, its actually better then the grinds where a transmission almost catches that gear, witch is a big problem with Honda's transmissions. Getrags shift forks are also impressive. I have never taken apart a transmission that didn't have shift forks that had two friction points at the far extreems of the fork. I've seen them wear some, especially on honda's and some on Fiero 4 speeds (4.10:1 model) and worse, a weak cast aluminum piece like the one on the Fiero Isuzu's transmission, witch sometimes break from force. The Getrag has something I have never seen on any other transmission. It is an alumium piece like the isuzu, but the casting is different. The fork only has 1 pair of friction surface's on it, the top and the bottom The WHOLE arc of the fork rides inside the engagment collar, its the only transmission I know of that has this, The fork cannot break, and wear is distributed amongst a LOT of metal as opposed to being consentrated on the tips of the forks.
Getrag's bearings are about the same as Honda's witch are the best. The drivers side ends of the input and output shafts ride on closed bearing sets, meaning they are almost sealed, with exception to having areas for lube to get in. Im pretty sure these are actually ball bearing so they can handle thrust loads, the shafts are actually bolted to the bearing, so all the thrust loads are handled by these bearings alone. They are also inherently very low friction. The other ends are handled by fat needle bearings witch can handle great side to side loads, and they are as well very low friction. The differential carrier bearings are like wheel bearings, They require VERY specific shimming and spacing in order not to either burn up, or have slop. I like the Honda's bearings, they use VERY heavy duty ball bearing differential carriers, they require a very simple shimming procedure, and are nearly fail proof. If the getrag had this it would be one step closer to perfection.
The differential itself, is pretty stout, The ring gear is about 1.25" thick, witch is borderline overkill. Diff carrier has a hardened steel pin holding the spider gears in place, thats about the best you can get before a posi unit. This unit can be broken by doing long burnouts. Thats the nature of the open differential. Overall though, the Getrag is one tough transmission, Weakest point being the differential spiders, from a sheer torque standpoint. If you do burnouts, you might also take the differential pin with the spider gears. Im not seeing any possibility of chewing off the teeth on any part, no wearing on the shift forks, and pretty tough synchros. I cannot fathom what kind of force it would take to break a getrag that does not have differential abuse wear, nor witch part would break, Input shaft maybe, But I dont know for sure. I would like to here some stories of what went wrong with Getrag's.
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Report this Post11-28-2004 06:10 PM Click Here to See the Profile for Formula88Send a Private Message to Formula88Direct Link to This Post
In almost every case of Getrag failure I've heard of the case torqued or cracked and the differential blew. That or there was a clutch failure that took out the transmission. I think mounting the transmission as to limit the torque on the case would help a lot. Also, heavy wheel spin, since there is no LSD, can cause 1 wheel to spin much faster than the other and blow out the spider gears. Again, another differential failure.

Always looking for more data, though.

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Fierobsessed
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Report this Post11-28-2004 06:24 PM Click Here to See the Profile for FierobsessedSend a Private Message to FierobsessedDirect Link to This Post
Was it that the case went and the diff followed? Or was it that the differential blew and that broke the case? If you have heard of a blown getrag that didn't have a differential failure, I'd like to see it.
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AaronZ34
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Report this Post11-28-2004 06:33 PM Click Here to See the Profile for AaronZ34Click Here to visit AaronZ34's HomePageSend a Private Message to AaronZ34Direct Link to This Post
Imagine having a look inside a 284, offered on GM FWD 3.4L TDC equipped cars. Every part is about DOUBLE the size of a 282. I was also amazed. But somehow I still managed to **** up a 284 with a 3.4L TDC...That was only running high 13s...

Here is the story. I was at the track, expecting to run a high 13 or even a flat 14. This is in the white car in my sig, with a new(rebuilt by me, so a few minor interior mods) motor and equal length headers. The 14.7 was without the new motor and headers. So first run, I was using some drag radials, and the guy said you'd better wamr them up. So even tho I don't like doing burnouts in the water pit, I took his advice. I used 1st gear, and the car pulled right out. I was pretty embarassed. So I backed up, and did it again, but as soon as it started, I went for second gear that way it wouldn't pull out. I used the clutch, got it all the way in, let off the gas, and pulled the shifter back(all this was done hard, like a race shift). Well I thought it had grabbed 2nd, but it hadn't. So I let off the clutch, and mashed the gas to WOT, still pulling the shifter back. I guess I couldn't hear the grinding over a 3.4L pegging itself at 7150rpm. Yah it messed up the 2nd gear synchro REALLY bad. But I am simply amazed that it didn't drop the entire tranny or at least drop 2nd. It still has a 2nd gear, and I still use it. I just have to be REALLY nice to get it in without grinding. But when racing it seems to hit 2nd just fine. Main thing is that I can't downshift into 2nd anymore.

Long story short, it is bulletproof, yet not to a 17yr old with high octane gasoline for blood.

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p8ntman442
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Report this Post11-28-2004 06:46 PM Click Here to See the Profile for p8ntman442Click Here to visit p8ntman442's HomePageSend a Private Message to p8ntman442Direct Link to This Post
Fieroobsessed, did you put in a limited slip when you had it apart? I agree on how they are stronger, just redid an izuzu this weekend, and the getrag is beefier, but also much harder to take apart in my opinion.
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Fierobsessed
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Report this Post11-28-2004 06:49 PM Click Here to See the Profile for FierobsessedSend a Private Message to FierobsessedDirect Link to This Post
I can only imaging what kind of damage that did. Most likley, you ground down the engagment ring, and the teeth it engages to on the gear. Thats one way to break it. But, again, thats not overstressing the transmission, just abusing it in the worst way.
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Fierobsessed
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Report this Post11-28-2004 06:52 PM Click Here to See the Profile for FierobsessedSend a Private Message to FierobsessedDirect Link to This Post

Fierobsessed

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Who said I put it back togather? lol. And I agree, its much harder to split and reassemble. I'm going to hate putting in the detent/interlock block back in. But then again, I think Rodney's directions will come in handy.
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Report this Post11-28-2004 07:00 PM Click Here to See the Profile for WillSend a Private Message to WillDirect Link to This Post
I pulled apart a transmission from a W41 Oldsmobile. The owner had apparently liked doing one-wheel-wonder burnouts. The thrust washer between the differential case and one side gear had galled into the diff carrier and worn itself into shreds of steel that had adhered to the magnet in the case and the one in the VSS. The washer on the other side was heavily worn. All the other components of the transmission looked fine (thankfully including the 3.94 final drive and 1.03 4th gear set).

The center distance between input and output shafts is one of the biggest factors determining the amount of punishment a transmission can take. The 282's shaft center distance is 76 mm. Do you know the shaft center distances of other manufacturers' transmissions? Most particularly the Honda boxes and the Mitsu boxes used in AWD DSM's...

I wonder if I should start looking for HD replacement bearings for the 282... maybe with a little machining of the diff carrier...

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Report this Post11-28-2004 09:23 PM Click Here to See the Profile for AaronZ34Click Here to visit AaronZ34's HomePageSend a Private Message to AaronZ34Direct Link to This Post
I'll have mine out come X-mas time, I'll get some pics of the inside of it to see how bad it is. But the GM Synchromesh that I changed a few months ago still looked clean...lol

Mine is weird. When I do burnouts, they aren't one wheeled. Both my wheels are spinning, leaving black stripes, and smoking. My passenger tire spins a bit faster, but it is very hard to tell.

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Report this Post11-28-2004 09:45 PM Click Here to See the Profile for oneblack85gtSend a Private Message to oneblack85gtDirect Link to This Post
sorry guys, im really bad with trans vocab :\

ok, question about the getrag's...what cars came with the gleason-torsen LSD? if u have the trans sitting on the ground, and both of the places that the axles are mounted into spin the same direction, that's LSD right? cuz if so...im a happy happy man

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Report this Post11-28-2004 09:57 PM Click Here to See the Profile for aaronrusSend a Private Message to aaronrusDirect Link to This Post
according to a gm engineer i met, john heinrichy, the 4 speed muncie v6 trannies are the strongest of the fiero transmissions, not the getrags..getrags are a close 2nd, but the 4speeds are more torque friendly
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Report this Post11-28-2004 10:34 PM Click Here to See the Profile for Formula88Send a Private Message to Formula88Direct Link to This Post
 
quote
Originally posted by AaronZ34:
Mine is weird. When I do burnouts, they aren't one wheeled. Both my wheels are spinning, leaving black stripes, and smoking. My passenger tire spins a bit faster, but it is very hard to tell.

That is what can blow your spider gears. The different speeds the tires are spinning is very hard on the differential.
Also, your burnout damage hit the weak link of the 284. The synchros. I've read that the transmission is seriously strong, but the synchros are the weak link.

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Report this Post11-28-2004 10:53 PM Click Here to See the Profile for p8ntman442Click Here to visit p8ntman442's HomePageSend a Private Message to p8ntman442Direct Link to This Post
awww, putting them back together is fun, wait till you replace output shafts and gears and find there are different output shafts for the same year, and then the shim situation, ugh, dont get me started, but if you need help, pm me and ill give you what I got in my head about rebuilding the 282.
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Report this Post11-28-2004 11:17 PM Click Here to See the Profile for wcapmanSend a Private Message to wcapmanDirect Link to This Post
Just to throw in a few comments. I run a Getrag behind a N*. It puts 250hp to the rear wheels and 225 ft.lb of torque at 2000 up to 275 ftlb at 5500. Torque curve is almost flat! That was measured on a chassis dyno in Huntsville. Good engine/lot's of torque. Getrag holds up just fine.

I think one of the reasons is that the transaxle case no longer supports the dead weight or the torque over from the engine. When this was all mounted up, a middle fore/aft member was added to the cradle and a mounting plate was installed between the engine and tranny that mounts to this plate. No engine movement relative to the cradle (you can do this with a N* because the engine is really smooth). If you look at a stock installation the engine is mounted on the front and the trany is mounted in two places at the opposite end. SO all movement of the engine, tranny combo results in twisting of the tranny case and extra case torque. Also all gravity loads are applied to the tranny case, which could be trippled for impact during actual driving conditons on a rough road. This twisting can change the alignment of the diff bearings under load.

I have another 282 built up with a Gleason LSD but it isn't installed inthe car yet. I was waiting until I have to replace the clutch but the Quartermaster just won't quit. I have heard opposing stories of the strength of the Gleason-Torson. Anyone with actual experience?

Has anyone else ever mounted a tranny like this? Zumalt's original SBC kit with rigid mounts was similar but from what I've heard no one could stand to have a SBC rigidly monted for any length of time because of the chassis vibration. I drove one once and hated it.

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Will
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Report this Post11-29-2004 12:46 AM Click Here to See the Profile for WillSend a Private Message to WillDirect Link to This Post
 
quote
Originally posted by oneblack85gt:

sorry guys, im really bad with trans vocab :\

ok, question about the getrag's...what cars came with the gleason-torsen LSD? if u have the trans sitting on the ground, and both of the places that the axles are mounted into spin the same direction, that's LSD right? cuz if so...im a happy happy man

What I've heard says that only a handful made it out of the factory in cars and all of those went to the racing program...
Pull your axles. If you see the cross shaft for the spider gears, then you have an open diff. If you see all the way through then you have a Torsen (extremely unlikely).

[This message has been edited by Will (edited 11-29-2004).]

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Fierobsessed
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Report this Post11-29-2004 01:28 AM Click Here to See the Profile for FierobsessedSend a Private Message to FierobsessedDirect Link to This Post
I think its safe to say that no torsen diff's made it to public market

As far as the transmission case taking a weight/torque beating. The only thing I have ever seen happen is the mounting bolt bosses shear off the trans case. Im willing to bet that the forces exerted on the transmission by engine weight are less then negligable, I doubt they have any affect on the transmission. I dont think the cases are flexible enough for that to do any damage. But then again When you pull the front wheels off the ground, the differential is the "hinge" that the car lifts apon. Lots of force involved there.

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Report this Post11-29-2004 10:52 AM Click Here to See the Profile for WillSend a Private Message to WillDirect Link to This Post
With an overall 12.6:1 first gear, 300 ftlbs at the input shaft comes out as nearly 3800 ftlbs at the axles. Since the rear transmission mount is less than a foot from the axle centerline, there should be between 5,000 and 7,500 lbs of force on the rear trans mount... no wonder I split the stock bracket into three pieces.

Actually, the force won't be that high because the other powertrain mounts take quite a bit of it, but I think that the lion's share is taken by the rear trans mount. At any rate, the forces on the mount during acceleration dwarf forces associated with engine weight. That's why I didn't have any concerns mounting the transmission like stock with my Northstar.

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p8ntman442
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Report this Post11-29-2004 01:10 PM Click Here to See the Profile for p8ntman442Click Here to visit p8ntman442's HomePageSend a Private Message to p8ntman442Direct Link to This Post
some gleason torsens are out there, last year i saw a couple get scoffed up by mantapart and sold for 1300 bucks each, now I think TRS has one for sale for 850. As far as 282's with gleason torsen limited slips being sold at a dealership, I dont think so, in fact I dont think it was an option on the w41 cars when purchased. They were added to some of the w41 cars (w40 clones into w41) no true w41 had a torsen in it, or was raced, they were w40's that were given the Hot #2 w41 grind cams, baffled fuel tank, and limited slip. The car and driver car, thats tested in the magazine to produce a 14.6 quarter mile time, has a sunroof and black background center caps on the wheels instead of silver. (hmmmm how many of the 204 w41 cars had the sunroof option?????????? extra weight what? , it wasnt a from the showroom w41, it was a jacked up w40 car. which may have had the gleason torsen).
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Report this Post11-30-2004 10:09 PM Click Here to See the Profile for wcapmanSend a Private Message to wcapmanDirect Link to This Post
From an engineering standpoint, EVERY load exerts some strain on the parts. Strain is movement under stress. In other words EVERYTHING deflects to some extent. Dead weight of an engine on a tranny case is multiplied many times over during impact loading , such as hitting bumps, etc. Put a dial indicator on a tranny inner bearing race. Then apply a few hundred pounds to the tranny mount and watch the dial move. Bearings don't like things moving more than 0.0005".
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Report this Post12-01-2004 12:28 AM Click Here to See the Profile for Golden86Send a Private Message to Golden86Direct Link to This Post
Reading this thread ALMOST makes it ok to be going through all this trouble in finding a getrag over an isuzu. After my auto to 5 speed conversion I think I will be happy I chose the getrag over any other trans, even the muncie 4 speed.

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Report this Post12-01-2004 09:00 AM Click Here to See the Profile for spearceClick Here to visit spearce's HomePageSend a Private Message to spearceDirect Link to This Post
This is what happens to a 282 Getrag when you do a high RPM launch with sticky tires and really good clutch


The syder gears came through the case and took a chunk out of the pressure plate

Steve

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Report this Post12-01-2004 09:50 AM Click Here to See the Profile for brysonSend a Private Message to brysonDirect Link to This Post
So it's looking more and more like if we can find a stronger differential, the transmission will be able to handle more power...is that the general idea?
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Report this Post12-01-2004 06:55 PM Click Here to See the Profile for FierobsessedSend a Private Message to FierobsessedDirect Link to This Post
Did you do a burnout before the transmission blew?
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Report this Post12-01-2004 07:53 PM Click Here to See the Profile for WillSend a Private Message to WillDirect Link to This Post
What kind of 60' time had you been getting? What kind of tires and how high did you rev it? How often did you do this, and how much power are you making?

My transmission handles 12's just fine, but I feed the clutch rather than dumping it.

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Report this Post12-01-2004 09:29 PM Click Here to See the Profile for FrugalFieroDirect Link to This Post
I was there when spearce blew that tranny and it wasn't pretty. You know its not gonna be good when you can't even move/push your car (cause the differential is swiss cheese) and its taking a leak all over the track as you are looking at the hole in the tranny case!

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Report this Post12-02-2004 01:03 PM Click Here to See the Profile for AaronZ34Click Here to visit AaronZ34's HomePageSend a Private Message to AaronZ34Direct Link to This Post
 
quote
Originally posted by Will:My transmission handles 12's just fine, but I feed the clutch rather than dumping it.

So will 400+ hp at 8,000rpm be too much for the 282?

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