5spd transmission damage?

[toshts]

Had a 5spd fall into my hands, couldn't resist the price of free and the tail housing around the seal sits is dented in a little. 

 

 

Needs a real good clean but I'm wondering if the dents a problem and if its fixable? Appears to be from a later 620, should bolt right up to my lz if I get the dent sorted. 

[Draker]

It's fixable, but you'd have to be pretty careful. Since it's aluminum, if you try to bend it back out it'll just crack. You'd have to add a lot of heat in that area, then could probably be bent back to round. Still a bit risky. you could also.... just run it. If it has issues, then try fixing. That's probably what I'd try first. Most likely the seal will wear quick in that area. Or maybe wear the drive line over time. 

 

[toshts]

Gotcha, I was considering taking a socket or other tapered round piece of hollow metal that's a similar size and trying to lightly pry or tap it back into shape but I am a fan of the running it and seeing what happens idea

[Draker]

If you do, you really need to add heat. Otherwise it WILL just crack and snap off.

[datzenmike]

That probably impacts the seal so pop it out, needs to be replaced anyway, and tap the aluminum till it is more round along with the steel dust shield.

 

If there is only a reverse light switch it's not from a 620. The FS5W71B was optional on the '77 model year and was a mid ratio five speed with the '79 having a wide ratio to go with the 4.11 differential that year only. The 4.375 and mid ratio five speed were an option that year.

 

If curious which of the two you have, place in first, mark the input and output splines. Turn the input 20 times while counting the output turns.

 

Wide ratio.... 5.5 output turns

Mid ratio...... 6.0 turns.

[Draker]

22 minutes ago, datzenmike said:

That probably impacts the seal so pop it out, needs to be replaced anyway, and tap the aluminum till it is more round along with the steel dust shield.

 

Probably true about the seal, but if you try to bend it back without heat it'll crack. Map gas should help here.

[ggzilla]

so how would you do it, something like this?

 

* remove seal

* stick a large socket into back (just to cover the open hole and prevent the gear lube from catching fire)

* heat the bottom flattened are with MAPP gas torch. How hot, it won't get read like iron does

* then what? Tap the deformation?

[toshts]

3 hours ago, datzenmike said:

That probably impacts the seal so pop it out, needs to be replaced anyway, and tap the aluminum till it is more round along with the steel dust shield.

 

If there is only a reverse light switch it's not from a 620. The FS5W71B was optional on the '77 model year and was a mid ratio five speed with the '79 having a wide ratio to go with the 4.11 differential that year only. The 4.375 and mid ratio five speed were an option that year.

 

If curious which of the two you have, place in first, mark the input and output splines. Turn the input 20 times while counting the output turns.

 

Wide ratio.... 5.5 output turns

Mid ratio...... 6.0 turns.

Got a new seal ordered, replacing it either way so might as well try and round it out best I can. 

 

Counted 5.5 turns, its a wide ratio. Has 3 electrical plugs on it. 

[toshts]

3 hours ago, Draker said:

 

Probably true about the seal, but if you try to bend it back without heat it'll crack. Map gas should help here.

I'll definitely take your advice and use heat, I'll probably run some gear oil rtv around the outside when installing to try and help make up for the deformation

[toshts]

A little wish full thinking here - would the tail section from a 4spd fit onto the 5 speed? I've got 2 of them sitting around and it'd be real convenient, if not I might start looking for a different tail shaft. Also what about from a d21 5spd? 

[datzenmike]

1 hour ago, toshts said:

Got a new seal ordered, replacing it either way so might as well try and round it out best I can. 

 

Counted 5.5 turns, its a wide ratio. Has 3 electrical plugs on it. 

 

Then from a '79 620 or possibly '80 720 2wd. I can tell if you post a picture of the rear driver's side of the tail.

 

Negative. A four speed is much different and does not have room for the 5th gear.

[toshts]

The tail bushing was pretty bad, I couldn't find just a tail section for sale locally and the cheapest 5spd I could find locally was 500$ so I called up my machine shop and sent him pictures of the damage and he told me to bring it in. 

 

 

He ended up making a cut in the damaged area of the aluminum, making a slight interference fit steel tool to press in and restore the shape, welding it back up from the outside and milling the excess off the inside. Seal fits perfect now, waiting on the new bushing to arrive for reassembly. 

 

Also noticed this gear has some decent chips, after looking at diagrams I think it's the reverse idler gear?

 

 

After reading other posts I'm gonna go back in and count the gears and potentially order a new one but is the reverse idler gear between the 4spds and 5spds if they have the same tooth count? Also read you could just flip the gear around if it's damaged on one side, is that just because the other gear engages with it from the top? 

[ggzilla]

Yay, a good machine shop is a treasure

 

47 minutes ago, toshts said:

The tail bushing was pretty bad, I couldn't find just a tail section for sale locally and the cheapest 5spd I could find locally was 500$ so I called up my machine shop and sent him pictures of the damage and he told me to bring it in. 

 

 

He ended up making a cut in the damaged area of the aluminum, making a slight interference fit steel tool to press in and restore the shape, welding it back up from the outside and milling the excess off the inside. Seal fits perfect now, waiting on the new bushing to arrive for reassembly. 

 

[ggzilla]

Why bother to replace the idler gear -- does it make noise when you shift to reverse? From the photo it looks like they shifted to reverse more than once while the car was moving and ground the gears. But it looks like slight damgage. I don't think you can flip it over as the teeth are flat on the front edge

 

49 minutes ago, toshts said:

Also noticed this gear has some decent chips, after looking at diagrams I think it's the reverse idler gear?

 

 

After reading other posts I'm gonna go back in and count the gears and potentially order a new one but is the reverse idler gear between the 4spds and 5spds if they have the same tooth count? Also read you could just flip the gear around if it's damaged on one side, is that just because the other gear engages with it from the top? 

[toshts]

19 minutes ago, ggzilla said:

Why bother to replace the idler gear -- does it make noise when you shift to reverse? From the photo it looks like they shifted to reverse more than once while the car was moving and ground the gears. But it looks like slight damgage. I don't think you can flip it over as the teeth are flat on the front edge

 

Gotcha I might have misunderstood other posts then - not sure never ran this transmission, it was a free listing on Facebook marketplace think it's been sitting in a garage since the 90s. But if it doesn't look bad I won't worry about it, just thinking that I've got 2 spare 4spds and if the gears the same might as well. Gears are also pretty cheap to order and it's all apart anyway

[datzenmike]

Reverse gears are all straight cut so same on either side of the tooth. You should be able to turn it around. Why don't you try and get back to us? count the teeth as well

 

The 720 4 speed reverse idles is unique to the 720 and only used through '82.

 

The 5 speed idler comes in two flavors 22 and 23 teeth for the two transmission ratios, wide and mid range. Both part numbers do not match the 4 speed.

 

 

Even if noisy while reversing just how far do you drive in reverse 1 mile for every 30,000 forward miles???? Forgetaboudit.

[toshts]

7 minutes ago, datzenmike said:

Reverse gears are all straight cut so same on either side of the tooth. You should be able to turn it around. Why don't you try and get back to us? count the teeth as well

 

The 720 4 speed reverse idles is unique to the 720 and only used through '82.

 

The 5 speed idler comes in two flavors 22 and 23 teeth for the two transmission ratios, wide and mid range. Both part numbers do not match the 4 speed.

 

 

Even if noisy while reversing just how far do you drive in reverse 1 mile for every 30,000 forward miles???? Forgetaboudit.

Gotcha, everything's at the machine shop right now and I don't think he's in today (one man operation, open random days of the week depending on what else he's got going on) so I'll get a tooth count when he's back in. He was mainly worried about it chipping more and the chips damaging other gears but knowing it's reverse now I'm not too worried about it. 

[datzenmike]

Oil is much lighter than even water so any chips will sink to bottom of transmission and the drain plug has a magnet on it. Don't worry. See if the gear is 'reversable'.

 

On the L series 280zx there are three reverse idlers for the wide, mid and close ratio transmissions. 

[toshts]

I got the transmission back from the machine shop today and am having trouble with reassembly. It currently has the front housing attached and reassembled with just the tail housing left for me to put on. I held the shift rod fully to the side so it cleared the forks, gently wiggled it down into place, it fully seated, got the shift rod lined up in the forks, hand tightened the bolts to let the rtv cure and put the shifter back in to test it out before putting it in the truck. I have 1st and 2nd, it shifts over to the 3rd and 4th slot but doesn't go into either of them or into the 5th and reverse slot. Pulled the tail housing back off thinking I'd misaligned something and the middle of the 3 fork rods doesn't move up or down. The outer 2 fork rods do both move up and down into place just fine. I have the tail housing off my old 4spd and all three fork rods move up and down, assuming their supposed to be able to do that?

 

When I first picked this transmission up I threw the shifter into it to test all the gears and it went into all 5 with no problem. Not sure if I didn't line them up properly or if the middle fork is seized now, need some guidance on what I'm doing wrong. 

 

Sorry no pics - my internets down so I can't use my computer to upload them but will when it's back up

[toshts]

Think I figured it out, the middle rod moves fine when rod on the bottom that sides the fork in the tail is up in it's middle position (sorry not great descriptions) but everytime I try and put the tail section on it dropped back down, any tips on how to keep it in place? 

 

[toshts]

Turns out the bolts that hold the check balls were all loosened all the way, realized when one fell out lol. Tightened them, set the forks in neutral, reassembled and have all gears now 🙂

[Thomas Perkins]

Hey toshts.Is Donnie Roberts a trusted parts seller?Do you know him?He is up in Oregon too.He sells a lot of Nissan parts on Facebook.

Edited Tuesday at 05:16 AM by Thomas Perkins

[toshts]

4 hours ago, Thomas Perkins said:

Hey toshts.Is Donnie Roberts a trusted parts seller?Do you know him?He is up in Oregon too.He sells a lot of Nissan parts on Facebook.

I've messaged him a handful of times for different things but he's never had what I was looking for - always was nice and professional but never ended up buying from him. He lives pretty close to me, if he ever gets a brown/beige interior parts truck I'd probably buy from him, prices are a little on the higher side though

Edited Tuesday at 09:43 AM by toshts

[Thomas Perkins]

9 hours ago, toshts said:

I've messaged him a handful of times for different things but he's never had what I was looking for - always was nice and professional but never ended up buying from him. He lives pretty close to me, if he ever gets a brown/beige interior parts truck I'd probably buy from him, prices are a little on the higher side though

Thanks.

[toshts]

Calamity

 

 

Guess I'll be filling it through one of the sensors lol

 

I was surprised at how easy it was to get the trans in/out of the truck. It is 2wd and I had the manifolds removed so best case scenario but it only took me about an hour to get the drivetrain out and roughly half an hour to get the trans back in and mated to the engine (not including crossmember or driveshaft). All the other transmissions I've pulled with the engine still in have fought me tooth and nail both when removing and installing and I even had extra hands for most of them. Gonna finish reinstalling everything, let the rtv finish curing then hopefully give it a test drive tonight if all goes smoothly.