Help PLEASE

hey heres the deal, i have a 1990 mazda 2200 x-tended cab. It WAS an automatic but i fried the tranny, well turned out to only be the converter, but i didnt find out AFTER i had the 5 spd in. Anyways put the new starter, clutch, brackets blah blah in and i have NOOOO power off the line and it wraps just short of 4000 rpms at 75 mph. Is my tranny screwed or do i have to switch to a 5 spd rear end or what??? Help i gotta take an 8 hour trip home every couple months and its KILLING my baby!!! <img src="{SMILIES_PATH}/icon_sad.gif" alt=":(" title="Sad" />

I can't see that the tranny is screwed up but the rear could have diferent gears in it and the auto rear ends do have that plug on the front of the pumpkin is that not to help with shifting the auto tranny into a overdrive gear.

The plug ontop of the rear diff is usualy for the ABS. Atleast most of the mazda's i've worked on thats what it was for.. my toyota's had that too.

Okay atleast we know what that is for now but is the rear ends geared differently enough to make tha big of a change.

the auto and 5 speeds are geared differently i had the exact same prob with my 75 datsun standard cab

I may be wrong but I think that all B series have 1:3.91 rear end gear sets whether a/t or 5 speed.They are not geared for top end but for low to midrange pulling power.Thats why most of us complain about no top end.My truck broke into the 90 mph range only after it was modified.Lol.BJ &quot;Artificial intelligence is no match for natural stupidity.&quot;

Bump.The overdrive in the a/t is electric and the rear end has nothing to do with it shifting into o/d.There is a solenoid on the tranny that does that.BJ

According to the MazdaTrucking site BJ is correct - M/T &amp; A/T both use the 3.909 to 1 rear end gearing. The final gear ratio in the transmissions differ, but not enough to accout for the RPM issue. I can say that at 75 mph my daughters truck does run around 3,400 rpm with 18&quot; rims.

And at 75 mph my 2200 with automatic is turning 3200 rpm with 15 inch rims,so I suspect the rpm differnce may be due to tire size and not tranny,assuming ur daughters truck is a 5 speed.BJ

Next tachs on Bseries are electric but the speedo is gear driven.Did u happen to swap the speedo cable out of the 5 speed truck when u put the tranny in or did u use the speedo cable out of the a/t truck?If u r turning 4000 rpm in a 5 speed truck and only running 75 mph,something is out of sync.Try having someone match your speed on a stretch of open road and see how fast they are going versus how fast u r going.I bet ur speedo is off.BJ