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Crashtd420

A 521 in Massachusetts

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Well I'm glad I started removing the tail housing.... it did break the bond, so it definitely would have leaked..... and it really needs a cleaning.....

 

On to my problem.... its loose, I can get about a 1" gap but that's it..... 

The only thing i see hanging on is the rod that is connected to the shifter....

20181214-135816.jpg

 

I see the pocket where the shifter goes is sliding into the tailhousing.....

20181214-135822.jpg

 

So does the rod stay in the tailhousing or with all the internals?

 

 

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So I left the transmission alone for now.... I was able to put my new cap and rotor on.....

20181214-150536.jpg

 

123 ignition sells the only correct rotor.... and instead of the beru they sell I was able to cross reference the number to a oem bmw part right from Germany..... 

Hopefully next year I dont have that miss fire come back..... 

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Yes, the rod stays in the tailhousing. Inside the tailhoising at the end of that rod is a finger which protrudes down into the gets where it contacts with the three rods mounted in the mid plate. It is free to move, and only connect via push pull motion. Just twist the tailhousing around and it should come loose, at which point you can see what it looks like to make more sense.

 

 

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Success..... 

So these are I believe the gates stroffgren was talking about.....

20181216-140901.jpg

 

This is the rod connected to the shifter....

There is a small bar that engages the gates.....

20181216-141133.jpg

 

To separate I did remove this...

20181210_171152.jpg

There was a spring, and something else .. I just pulled the spring out because things were a little stuck inside and I didnt wanna loose it.... 

But I was able to loosen the end a little.... this allowed me to rotate the shifter end and the rod on the inside further right which disengages the gates.... then you can pull the housing further off but  you get hung up on a bearing, rotate rod slightly left and housing will slide right off..... 

 

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I'm glad I went through the extra effort.... I could really examine the gears and bearings....

Front ...

20181216-141117.jpg

 

Rear...

20181216_141104.jpg

 

I did notice some damage to one gear.... luckily just the edge.....

20181216-141059.jpg

 

Doesnt seem like anything I need to worry about, all the syncros seem new, and all the bearings are great..... the way this was glued together I almost think it was rebuilt before I ever got it..... 

Now to wash the cases.... they are nasty...

Edited by Crashtd420
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Reverse idler gear. All other gears and in constant mesh so no grinding. Reverse has no synchro ring so you have to manually mesh it and often if the vehicle is not stopped the gears will clash. If damaged they might howl a bit but reverse is not used much anyway. They are also straight cut and not as quiet and cheaper to make.

 

 

20181216_141104.jpg

 

See the big nut on the mainshaft lower right just behind the speedometer pinion worm drive? Make sure it's not loose. It should be staked to the mainshaft so you may have to pry that loose to tighten it some more then re-stake it.

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I did find this place while looking for info and parts for the 71 series transmission....

 

https://www.midwesttrans.com/FS5W71_Manual_Transmission.html

 

While they had standard rebuild kits with bearings and syncros,  they also had alot of the other parts too, like gears and shift forks and more.... I looked under diagrams and found alot more parts and info than if you tried searching for a vehicle.... 

 

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1 hour ago, Crashtd420 said:

I did find this place while looking for info and parts for the 71 series transmission....

 

https://www.midwesttrans.com/FS5W71_Manual_Transmission.html

 

While they had standard rebuild kits with bearings and syncros,  they also had alot of the other parts too, like gears and shift forks and more.... I looked under diagrams and found alot more parts and info than if you tried searching for a vehicle.... 

 

 

Damn looks like they sell rebuilt 5 speeds. What model year would drop into a 521???

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I was seeing that.... I thought I saw one that had the 12" tailhousing..... but I cant find it now.... I think the 83to85 has the short one but I think you would still have to get the correct bellhousing...... 

But they also call it a 71f?

So I'm not sure what that's about.... 

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Yeah, you’ll lose 5th if that nut comes loose, so stake it into place. It’s a very common problem on 5 speed roadsters.

 

Interesting about the reverse idler. My 4 speed clashes in reverse sometimes even when I’m stopped. One of the shafts takes a while to slow down, and it will grind for a split second as it meshes. It does it mostly when it’s cold out. Kind of annoying.

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Ya I found it again under the 83 720.... and it does have the wrong bellhousing....  

Screenshot-20181216-192108-Chrome.jpg

Even the 1980, which I believe is an L20b, is showing the same longer transmission the same bellhousing...

   ( not for the L series)

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Just now, mainer311 said:

Yeah, you’ll lose 5th if that nut comes loose, so stake it into place. It’s a very common problem on 5 speed roadsters.

 

Interesting about the reverse idler. My 4 speed clashes in reverse sometimes even when I’m stopped. One of the shafts takes a while to slow down, and it will grind for a split second as it meshes. It does it mostly when it’s cold out. Kind of annoying.

Ya while its appart I'll make sure, easy insurance..... 

I'm glad the whole gear isn't bad.... 

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They never made a short 5 speed with an L case except for the dogleg 5spd, if looking for that transmission search 1977-79 Datsun 200SX 5spd, just keep in mind that it is not really a good transmission for a truck.

But you can make one out of a 85/86 shortshaft 5spd and a front case off a 1980 720 truck with an L block in it, they made every part you need, they just never put it together that way at the factory.

Edited by wayno
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3 minutes ago, wayno said:

They never made a short 5 speed with an L case except for the dogleg 5spd, if looking for that transmission search 1977-79 Datsun 200SX 5spd, just keep in mind that it is not really a good transmission for a truck.

I was just trying to see if they sold anything with an L case.... doesnt look like it..... only seems like 80s on up for full transmissions,  nothing with an L series bell.... 

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19 hours ago, datzenmike said:

See the big nut on the mainshaft lower right just behind the speedometer pinion worm drive? Make sure it's not loose. It should be staked to the mainshaft so you may have to pry that loose to tighten it some more then re-stake it.

Bingo! Most common failure on these transmissions.

 

A loose nut will allow the gears to knock back and forth and over time, that causes the thrust washers to have grooves worn in them. If the nut is loose, and you tighten it, check the end play of the gears. If there isn't any, the thrust is gone and the gears will weld themselves to each other. I've had this happen to me twice.

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The early 5 speed transmissions only had a nut. If it loosened reverse and fifth become unstable. (I had a '78 620 5 speed that lost 5th and a week later 2nd. Wish I had kept it and taken apart. In a way it got me interested in transmitions) Later the nut has a skirt that can be staked into a slot in the mainshaft. It's torqued to 100- 125 ft lbs. If staked it can't come off but wear can leave it with no torque. I have a high mileage '79 280zx 5 speed and the nut was wiggly. I un-staked it and gave it a good crank with an adjustable wrench with a pipe on the handle... it turned less than 1/4 turn and I re-staked it again. 

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Can I buy one of those 5 speeds and simply swap my L bell housing in it?  

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Last winter, Feb 2018, I got a L-20-b engine and five speed transmission out of a 1980 720 2 wheel drive truck.   On this transmission, the bell housing is NOT removable.

 

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Daniel they are actually talking about the front case not just the bellhousing like a chevy transmission.

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40 minutes ago, d.p said:

Can I buy one of those 5 speeds and simply swap my L bell housing in it?  

No you need a bellhousing for the 71b series with the L bolt pattern.... 

The 4 spd you have is the 63 series....

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The only good thing is it uses the same speedometer pinion.... so you can reuse that from your 4spd....

 

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3 hours ago, Crashtd420 said:

No you need a bellhousing for the 71b series with the L bolt pattern.... 

The 4 spd you have is the 63 series....

 

So I can buy one of these and get a bell housing from a 71b transmission with an L bolt pattern?

Edited by d.p
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The FS5W71B came on the L series 4 and 6 cylinder, the Z series, the SD (diesel) and the CA series through '86.5. Pardon the pun but in all cases the only real difference is the front case which has the engine bolt pattern. You can put a 4 or 5 speed L series front case on any of them to convert them for L series use.

 

The FS5W71B came with 3 distinct gear ratio sets relative to each other that are wide, mid and close ratio. 

 

The FS5W71B transmission is 31.5" long with the exception of the Z series which may also come in 26" length. If you have a 521, 510, 710, A10 or S10 that came with a stock 26" 4 speed the 720 26" 5 speed with an L series front case would save you shortening your driveshaft.

 

The 5 speed from a 4x4 720 will not have provision for a speedometer drive. This can't be altered. Using the GPS on your phone is bull shit, do it right on a vintage 521.

 

All FS5W71B from '85 through 86.5 have a larger 62mm counter bearing that will not fit the 56mm hole in L series front case. Just pull the 62mm bearing off and replace with the proper 56mm bearing and good to go. In this case use the L series cover plate that has the corresponding 56mm cavity in it. Possibly the 1st/2nd shift rod in the '85 and up transmission my be 16mm wide rather than 14mm wide hole in the L series front case. Just drill it out. 5/8" is just 0.005" smaller than needed but will probably work. The other shift rods are the same.

 

 

 

 

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