Datsun Roadster Forum-311s.org

Hi all,
I really need some help here, last weekend I took my 68 SRL out for a spend , twice since car was put together, cruising about 90 miles on the freeway all of a sudden the 5th gear went neutral on me, now I don’t have 5th gear but able to get home without problem. Got home reverse in to garage NO reverse so now I lost 5th gear and no reverse on the same day, prior to this all gears plus reverse were good shift nicely in all gears.

I called Skip Miller over at Pasadena and explained my situation to him, he said I might have to replace the reverse and 5th gear.

So my question is has anyone had this issue before and able to salvage 5th and reverse gears?
and when you lost your 5th gear did you also lost your reverse?

Thanks all
vinh

DO NOT DRIVE THE CAR! It sounds like the mainshaft bolts have loosened and backed off. This is not the same failure I have had with 5th gear. Your transmission could self destruct at any moment. Its time to pull the engine and trans and take a look.

Sorry to be the bearer of bad news, however there is a bright side, it hasn't blown up and you might be able to save the whole 9 yards. You won't know until it comes apart however.

Will

Will,
When I try put in reverse I feel a little grinding, could this be bad news? that was after I had these issues

Pulling the motor is no problem, I put the whole drive train in and am able to remove it but when come to taking apart and rebuilding the transmission I have no clue.
I have posted on wanted list for purchase or rebuilt transmission, any help here?
vinh

Hi Vinh,
Skip Miller at Miller Imports will be able to diagnose what the problem is and fix it.
I would be scared to drive the car, so might want to get it towed.
I'm sure Skip will also check the slave cylinder, slave hose, clutch pedal pin as well for you.
Good luck, sorry about the trouble.

Linda

The reason I think its the mainshaft nuts is because 5th and reverse are next to each other, and when the mainshaft nuts back off, neither one can engage so you have both neutral. If driven more, those nuts that are just loosened could fully back of and the whole inside of the transmission will start to slip and slide causing all kinds of issues, and could lock (In theory.) If you pull the whole mess out, and take it to the shop, they can pull it apart and find out what happened pretty easily.

After killing 3 5th gears, one being welded, the only thing that happened when I had issues was that 5th started to slip like the clutch was slipping, and then it went neutral. Reverse worked fine. The fact that your reverse is not fine, points fingers at the mainshaft nuts. I'd vote better safe than sorry. If its just the 5th gear for some reason, a new splined one is about $400 from Dean (if I remember correctly.)

Will

Linda,
I have spoken with Skip Miller. to save dollars, I told him I can bring him the tranny and have him rebuilt it, the price he quoted me (labor only, parts not include) is out of my budget.

Anyone out there have one for sale, or rebuilt for me and I will pay you?
Vinh

Vinh,

I would bet almost anything that Will is right that the main shaft nuts came loose.

You may not need to rebuild your trans.

Mine came loose once and I fixed it without taking the engine out completely, just pulled the radiator and move it forward.....
I don't suggest you do it that way, but you can pull the trans and rear housing without too much trouble. If the nuts backed off, you will need to reassemble and tighen the xxxx out of them.

Hey Phil,
You made it sound so easy perhaps it is, I don’t know, I never done it before. Just concern I might do more damage to it.
When the Tranny is out, how do I get to this nut, can I just remove the back housing and it there?
Does anyone have pictures to guide me where to tighten or fix this issue?
Again as I stated earlier on my post, all gears shift nicely without issue, even down shift. So I hope I didn’t screw up any gears inside.

thanks

I think we have had a similar thread on the board here a year or so ago. You might try searching the topic. It had pictures and a pretty good write up. I know a guy in San Luis Obispo who might be able to do it for a decent price. He has built mine, replaced 5th twice, and with the splined 5th in, its sweet. If push comes to shove, I can give you his phone # and you can get in touch with him.

Will

Will,
I might have to ask for that phone number if I dont find a replacement soon.

thanks
vinh

Datsundude wrote: When the Tranny is out, how do I get to this nut, can I just remove the back housing and it there?
thanks

The short answer is yes...
See Page 119 of the service manual "U20 5 speed"

1. Drain Gear oil
2. Disconnect Striking Rod from control lever. (gear shift from rod going into the gear box)
3.Pull up Split Pin and Release Nut and remove companion Flange from rear Extension. (remove cotter pin, nut and flange to U-Joint)
4. Release Fixing bolts and detach rear Extension Housing, disengaging Striking Rod From Fork Rods.
(Romove housing after unbolting..The rod that goes into the trans needs to slide into the housing a little. Its L shaped and engages into a slot of three rods that do the actual shifting of the sliders.

Phil

If you have a problem, post pictures and we will help. Be gentle..


LOL

Remove housing after unbolting..The rod that goes into the trans needs to slide into the housing a little. Its L shaped and engages into a slot of three rods that do the actual shifting of the sliders.

That L rod is called the "strike rod". The "L" portion of it is cast iron and can easily snap off if you're not careful when removing the extension housing.

Mike,
Could you post some pictures of the transmission guts for Vinh?
Thanks,
Phil

Here are two showing the area in question.

with the double nut, that will keep it from backing off right? splined or not? I know that when Brian rebuilt mine, he double nutted it, but I can't for the life of me remember if I got a splined gear or not. Should it matter at that point?