Powertrain locked up three times whilst driving today - anyone have thoughts?

We have a 1960 Bugeye with a 948 cc engine and Datsun 5-speed with the Rivergate kit and Gerard's bits for using the Datsun clutch/pressure plate.

A number of years ago, a friend was driving it and reported that the transmission had locked up on him in an intersection but he shifted to neutral and got going again. Subsequently we pulled the engine/tranny and had the transmission checked out again by the shop that rebuilt it and they found nothing.

Today, it happened three times that the power train locked up: chirp out of the right rear tire and I stop. My memory of the first two instances is that I was downshifting from second to first and thought that I'd hit both the brake pedal and clutch at the same time. Specifically, I don't remember what I did, but I ended up stopped and shifting into neutral then to first and carry on. The third time I think I might have been up-shifting first to second and realized that I definitely hadn't hit the brake pedal.

We just pulled it out of storage a week ago and today I put maybe 20 miles on it.

Looks like we'll be pulling the engine/trans this winter and I won't be driving it, except for maybe puttering around the neighbourhood (with no traffic), hoping it'll happen again.

There were no obscure noises or loud screeches or the sounds of things grinding and breaking, and everything seemed happy like always after each incident.

Anyone else had this (somewhat) less than pleasant experience? Suggestions? I'm assuming something to do with the clutch, but that makes no sense at all to me.

Thanks, Doug

I don't know how the ring and pinion are cut on this car, but a loose pinion can be pulled backward on trailing throttle and collide with the carrier, locking the diff when it gets to the squared off opening through which the spider and axle gears are serviced.
Bob

I'm with Bob on this Doug, I wonder if it doesn't have more to do with the diff. My first thought wasn't pinion but half shaft, possibly bent possibly cracked or chipped.

Thanks guys - guess I'll start at the aft end this winter. And the explanation from Bob and JP sure makes a lot of sense. We've hardly driven it over the last few years, partially because of my reliability concerns. Hopefully will be resolved this winter - I believe I've got replacement bits buried around here ('never throw out a half shaft'), and hopefully the problem will be obvious when we pull things apart. Thanks, Doug

You might diagnose my suggestion by pushing the assembled pinion backward and trying to move a wheel that is jacked up.
Bob

Actually, that sounds like a good idea to try, as it doesn't require immobilizing the Sprite. We have an A-H 3000 in the garage, so I won't be bringing the Bugeye indoors for disassembly until we put the 3000 away for the winter - being able to do the diagnosis sounds like a great idea. If it shows something, we could change the pumpkin (I swear I've got a spare around here somewhere) out on the driveway. Thanks! Doug

Dang! No smoking gun!
We pulled the axles and diff out and everything looks good: axle splines are straight and they rotate easily; the crown wheel/pinion look mint and minimal wear on the spider gears. No play on the pinion when pushing and pulling from the outside; no play when gently prying from the inside.
Fished out a spare 3.9 diff - and it's missing two of the spider gears (NLA at AH Spares and MOSS) and the shaft that they should ride has been pulled and put back in but is really tore up. Plus the carrier has a bend in it. Looks like I've got a small boat anchor.
We're about to take apart a wire wheel third member I've got and if it looks good, we'll put it in (and get the 3.9 ratio) and see if somehow magic occurs and there's no problems.
Probably we're looking at pulling the engine and transmission this winter, and getting the transmission disassembled again, hoping to find some wear points.
Ideas (brilliant and otherwise) much appreciated. thanks for the suggestions thus far. Doug

We're putting everything back together with the original parts - when we pulled the last third member apart, we found that it had been sandblasted but whoever did the work had left the filler plug out, so there's sand in the diff area etc. etc. etc. And put the sandbox special back together, but label it. It's an early 60s quarter elliptical wire wheel assembly, so I'm thinking I might have the matching front end around here somewhere.
And we'll pull the engine/trans later this winter and see if we learn anything. Dang confusing. Doug

Sorry we sent you down the rabbit hole, but it was the most logical choice.
Bob

No complaints at all! Nice to check potential issues. ANd Gracie Slick sent a lot of us down the rabbit hole - and I enjoyed it! Doug

I went over your problem three times, and would have said diff. also. On my TR 6 a bolt backed off on the flange to my diff. and locked up my car I pulled my trans only to find the bent bolt at the diff. I do not know Datsun trans but if the shifting forks are worn or not tight to shifting shaft it could lock between two gears as most first reverse gears are not on the same cluster gear set. Step two go to a Datsun web page and ask them. Madflyer

Figure I'll putter around the neighbourhood tomorrow after everything's tidied up and see if anything happens.
We've got another bugeye project with a 1275 (that needs the longblock rebuilt) and the Datsun 5 speed, so will maybe swap engines/transmissions around and see what happens.
I did do an internet search for Datsun type 60 transmissions but didn't find anything; also dropped to Rivergate on the long chance that they might have heard something.
Doug

Are the Datsun trans easy to find and cost friendly to just swap them. How did you get the first one.

Madflyer

Madflyer said:

Are the Datsun trans easy to find and cost friendly to just swap them. How did you get the first one.

Madflyer

Click to expand...

they used to be - not rare and more and more expensive as they come from a Datsun 210

The transmissions are from the Aug. 1979 to 1982 Datsun rwd 210. And scarcer than hens teeth. I've got three, collected over many, many, years - don't specifically remember where or when. If you can pick one up, do so, as you can sell them for a (smallish) fortune.
Got the BE back together today and drove gently around the neighbourhood before tucking it away for the next few weeks. No sudden graunches or stops. Sleepless in Seattle? How 'bout confused in Calgary??

If you can’t find one at a res able price
the guys at rivergate can inspect nd rebuild your transmission
I had them check mine out and replace some synchros before I installed mine .
been a strong quite performer
Rivergate Restoration Products
340 Reavley Road
Sale Creek, TN 37373
423-332-2030 (Fax: 332-6914)
info@rivergate5speed.com