Scomber Posted January 27, 2016 Report Share Posted January 27, 2016 So my transmission is noisy, and it turns out there was quite a bit of metal flake in the lube. I'm not sure this transmission is going to live. This is (as I said) a 720 with an L20b, which means it's a 1980 model year.What years of trucks and motors will have compatible transmissions? I understand the Z24 leans over, but the tranny mates up? What are my options? Quote Link to comment
flatcat19 Posted January 27, 2016 Report Share Posted January 27, 2016 Trans will mate up, bit with the lean. You could swap the housings. Quote Link to comment
Scomber Posted January 27, 2016 Author Report Share Posted January 27, 2016 (stupid question) Quote Link to comment
Scomber Posted January 27, 2016 Author Report Share Posted January 27, 2016 Also, I'm in a climate with road salt. There aren't a lot of old ones around. What's the latest thing that works? Quote Link to comment
datzenmike Posted January 28, 2016 Report Share Posted January 28, 2016 I assume that you changed the oil? The '80 720 (I assume 2wd) has wide ratio gear set same as the '79 620. This is the only exact transmission other than another '80 720. If not concerned with carrying heavy loads a mid ratio transmission can easily be substituted. The following L series 5 speeds are all mid ratio... '77 and '78 620 '77-'78 280z '79 280zx (only this one year) '77-'80 810 and '81-'81 Maxima The only other L series 5 speeds are the close ratio only used on the '80-'83 non turbo 280zx. It will fit and work fine on an empty truck, but if used for work or hauling a heavy load you will find that first is harder to take off in. It's intended for lighter cars or cars with larger displacement engines and not a heavy truck with small L20B and 3.90 differential. Quote Link to comment
Scomber Posted January 28, 2016 Author Report Share Posted January 28, 2016 Thanks. Let me explore another avenue. If everything inside is too crunchy, how hard is it (with a clean space and normal hand tools) to take this thing apart and replace the shaft bearings? That seems like it would be relatively cheap, parts wise, but would... uh... stretch my skill set. Then I'd just live with whatever gear slop there was, knowing the thing isn't just going to go BANG on me. How big of bearing press would I need? Quote Link to comment
datzenmike Posted January 28, 2016 Report Share Posted January 28, 2016 Various gear pullers, some pretty specific to the 71B, a good press, snap ring pliers, wrenches..... The counter bearing is the most prone to noise and then failure, it's also the easiest to get at. Quote Link to comment
Scomber Posted January 28, 2016 Author Report Share Posted January 28, 2016 Hmmmmmmmm....................... Quote Link to comment
Scomber Posted January 28, 2016 Author Report Share Posted January 28, 2016 Would a 4 speed bolt up in the same spot without modifications? Does the 4 speed for the same truck have the same gear ratios, other than missing 5th? Quote Link to comment
datzenmike Posted January 28, 2016 Report Share Posted January 28, 2016 The 4 speeds are identical but... 4 speeds. Same thing the '79 620 is identical. All the others will work, not saying a 280zx won't work but best if truck is just for commuting. Quote Link to comment
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