TH350 vs. TH400?

[Belair-o]

Hi, I was prepping to install the speedo bullet housing in the tailshaft of my automatic transmission, and all of a sudden, I am confused about what transmission is in the car. The length of my transmission (21-3/4" from front of bell housing to rear of case) and the pan says it is a TH350:
10519

But isn't this speedo housing in my trans for a TH400?
10520
I had purchased a replacement TH350 speedo bullet housing before getting under the car, but now see that won't work. I assume I need to order the seal kit for a TH400, and return the TH350 bullet. Also, I was going to order a replacement driven speedo gear while I was at it, but don't know if the (red) gear like I have is universal, regardless of which trans I have?
Thanks, Doug

[Rick_L]

You indeed have a TH350, and for whatever reason it has a TH400 style speedo drive. I don't know the answer to your question, but if you look up speedo gears at a website that sells them, you should be able to answer the question. TCI transmissions is a place that has speedo gears and related info.

[Belair-o]

Hi Rick,
That is pretty weird that they cobbled on the TH400 tailshaft. Thanks for your help.
Regards, Doug

[Troy]

I have a 1968 Truck Turbo 400 in my '55, it has a bullet style speedo drive. Mine isn't in the tail shaft housing it's just up stream of the tail shaft housing in the main case.

[markm]

I have seen dozens if not hundreds of Th350s with that style of speedo, they came about in the late 70s when tall highways gears came common. I have switched tailhousings to the early style in the past nothing weird or strange here. The style you have is all I have seen on 700R4s prior to electronic.

[Belair-o]

Interesting about the trany configuration variations. I had no idea from cruising the net that there were any variances.
Regards, Doug

[markm]

If I recall the th350s with big speedo drive th350s also have commie metric threads on rear motor mounts etc.

[Belair-o]

If I recall the th350s with big speedo drive th350s also have commie metric threads on rear motor mounts etc.

Stinkin' commies!

[Belair-o]

FWIW, In case it helps someone down the road, or if I forget (with my oldtimer's disease) and want to know the answer next time I do the task:

I had asked how much trany fluid should I expect to dump when I pulled the speedo gear housing from my TH350? With the car level, I pulled the housing on a recon effort to see what parts I needed to try and seal the leaks, and dumped about 3 qts. of ATF. After plugging the housing back in the trany, and ordering/receiving the parts, I pulled the housing again, and this time got 1 qt. of ATF.
Regards, Doug

[markm]

FWIW, In case it helps someone down the road, or if I forget (with my oldtimer's disease) and want to know the answer next time I do the task:

I had asked how much trany fluid should I expect to dump when I pulled the speedo gear housing from my TH350? With the car level, I pulled the housing on a recon effort to see what parts I needed to try and seal the leaks, and dumped about 3 qts. of ATF. After plugging the housing back in the trany, and ordering/receiving the parts, I pulled the housing again, and this time got 1 qt. of ATF.
Regards, Doug

Had it sat for a while and the convertor drained back the first time.

[Belair-o]

Had it sat for a while and the convertor drained back the first time.

Hi Markm,
Yes, it had sat a while in the first instance, with the convertor draining, and I assume more converter draining at the second instance.
Regards, Doug