# SD25 Diesel transmission swap



## Nisseamer (Oct 15, 2013)

Hi Folks
I have a 1987 D21 extended cab with a 5 speed manual and SD25 diesel. It is stuck in third gear but the clutch seems to work fine. It won't shift out of third either while moving or stopped, but the clutch disengages the engine from the transmission as normal.

I was climbing a hill and when over the top went to shift and it wouldn't move. I yanked pretty hard once and it came into a neutral position but made quite a bit of noise....before I rolled to a stop I shoved very hard and managed to get it back into third (it wouldn't go into any other gear). It didn't grind while going in, it just finally and with great resistance went back in. I drove the last 80 km home in third without incident or any unusual noises. Managed to just squeak over the one hill that worried me by giving it everything it had at the bottom.

I just had the transmission overhauled a year ago at a transmission shop because it was howling third and starting to make similar noised in other gears. The shop said the bearings were completely shot....which made sense given the noise it made.

After the overhaul it had a faint whirring noise for a while but the original overhaul mechanic was too "ham-fisted" a driver to even hear it when i took it back to him for a test drive (or didn't want to!?). Now, after a year of only occasionally noticing that sound it started to make the same whirring noise (different than the previous growling of the bearings) a little louder in most gears, though not sounding critical at that point, and I didn't make it home (about 300 km).

I have had the truck for three years and the stick has always had a lot of play in it when shifting. I have had that in other vehicles so wan't concerned...I think it is only a nylon or teflon spacer/bushing required to fix it.

I live in a fairly remote part of the country (Canada) with the nearest mechanic shop over 100 km away from where the truck is at my home now. 

Question(s):
Is there another tranny that could go in that truck that would mate up to the diesel and existing drive-lines? I'm not too worried about gear ratios.
Any idea what might be gong on inside this thing?

It is my only vehicle so need to get it fixed very soon.

Thanks very much for any ideas or help you may have. 
Cheers

Gerry


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