Transmissions and tcases, decisions ??

[jekquistk5]

Alright so here is the situation. I have a th350 and 208 in the truck right now, I have no 3rd gear, and the shifts from 1st to second are sloppy as hell. I picked up another 350 with a 203 attached for dirt cheap, but it has the short output shaft. I also acquired an old sm465 with the ten spline output attached to a 205. Now I know a lot of you may say just double it, but I do not want to do that right now, in the future yes, but not now. I want to keep the auto, and would like to put the 205 in but the 208 will work as well. What direction should I head, swap outputs of the th350s, keep the 208, or make some sort of adapter to attach the 205 to the short 350? or sell everything and get the 350 rebuilt. Installing a part time kit in the 203 is out of the question. I just want/ need high gear for running the dunes in 2wd. Opinions?

 

[nvrenuf]

Imo, if you want to keep an auto then swap the outputs (fyi, complete tranny disassembly required) and reuse the 208 because of the lower low range ratio.

I would also keep the 203 range box and 205 as the beginning of a doubler parts collection. These plus a doubler kit and a 27 spline 205 input shaft and your set whenever you're ready to do it.

 

[Greg Ducato]

Imo, if you want to keep an auto then swap the outputs (fyi, complete tranny disassembly required) and reuse the 208 because of the lower low range ratio.

I would also keep the 203 range box and 205 as the beginning of a doubler parts collection. These plus a doubler kit and a 27 spline 205 input shaft and your set whenever you're ready to do it.

That is sound advice

 

[1979jimmy350]

throw a rebuild kit into the 350, you can get a rebuild kit, shift kit and maby a few goodies for the internals for under $200. a th350 is pretty easy to rebuild. And being that it is not a lock up converter you can just flush it you dont need a new converter

 

[jekquistk5]

I think I'll start swapping the output shafts this weekend. I want to do this on the cheap, because the dunes will be the only thing this thing is gonna run this year. I already have to spend another 700 on new 38.5's, so If I can save money and have a transmission that at least shifts with out a huge amount of lag would be nice.

 

[ryan22re]

A 465/208 combo is the exact same length as the th350/208 combo. Uses the same driveshafts and crossmember. All you'd have to do is mount a pedal/linkage and cut a hole in the floor.

 

[diesel4me]

Did you try the usual fixes to the TH350 tranny before condemming it??..no vacuum to the modulator,or one that has a ruptured diaphram wont upshift into 3rd gear at all,or wont till your going about 60 mph,and also feels like it slides into neutral as you let off the gas and "engauges" again if you apply the throttle again..they can also cause mushy or harsh upshifts into second gear too...if the detent cable is way out of adjustment it can affect upshifts also..

I bought a good truck once the previous owner said "had a blown tranny,no 2nd or 3rd gear",all that was wrong with it was the Edelbrock carb someone put on it wasn't set up correctly for the downshift cable linkage,and it was pulling the cable taught at about 3/4 throttle,I fixed that and it shifted perfectly once again..the tranny in my '81 G-10 van had only first gear & reverse when I bought it..I found a stripped plastic gear on the govenor,had it fixed in 15 minutes,and it shifted like new again..

 

[4X4HIGH]

Did you try the usual fixes to the TH350 tranny before condemming it??..no vacuum to the modulator,or one that has a ruptured diaphram wont upshift into 3rd gear at all,or wont till your going about 60 mph,and also feels like it slides into neutral as you let off the gas and "engauges" again if you apply the throttle again..they can also cause mushy or harsh upshifts into second gear too...if the detent cable is way out of adjustment it can affect upshifts also..

I bought a good truck once the previous owner said "had a blown tranny,no 2nd or 3rd gear",all that was wrong with it was the Edelbrock carb someone put on it wasn't set up correctly for the downshift cable linkage,and it was pulling the cable taught at about 3/4 throttle,I fixed that and it shifted perfectly once again..the tranny in my '81 G-10 van had only first gear & reverse when I bought it..I found a stripped plastic gear on the govenor,had it fixed in 15 minutes,and it shifted like new again..

TH350 trans have a kickdown cable which has NO EFFECT on trans upshifting. The only thing the cable is for is to downshift when you mash the skinny pedal and it isn't required as you can manually downshift for passing gear.

A bad modulator or no vacuum will cause the trans to not upshift until very high RPM's (usually like 4000-4500 RPM's). It's been a while since i've owned a rig with a TH350 but IIRC even with no vacuum to the modulator or a bad modulator you can start in first gear and manually upshift the trans and it will shift.

 

[lectric80]

Just to give you an idea, I just finished rebuilding my T350 in Krusty. It is a very simple operation, and you are already going to have the trans torn down to swap outputs. Rebuild kit with new clutches and steels cost about $90, I chose to buy a new torque converter in my case but as said you could flush it.

First year of lockup T350 was 1980 so if this is on your 83 it is going to be a T350C unless it has been swapped at some point in the past. There is a difference in the valve body gaskets between the two, so you need to be sure you have the right kit for your trans. I don't know what effect having a non-lockup converter will have, but I don't believe my converter is a lockup type. I could be wrong though. I sure hope it doesn't hurt anything, but I haven't gotten Krusty up to speed yet to see.