Transmission swap advice th400 to th400

[Bobert]

I am replacing my th400 that was rebuilt a year ago with an original out of a cucv with supposedly under 30,000 miles.

Should I use the newer torque convertor or the original?

Should I change the filter in the old one?

I never really liked how the rebuilt one shifted, it always revved higher.

What do you guys think? anything else I should swap over?

 

[nhdiesel]

My opinion/belief is to keep the torque converter matched to the transmission. The reason for this is that a torque converter is very good at collecting particles from the fluid...it works as a natural centrifuge and the particles collect inside it. You don't want to put a torque converter from a transmission with higher mileage or harder use into a fresh transmission, where those particles could get back into the trans. This is why many shops won't warranty a replacement trans unless you have proof that you replaced the TC at the same time.

This is also the reason to ALWAYS replace the torque converter when replacing or rebuilding a transmission. Oh, and flush the cooler and lines while its out as well!

Jim

 

[BKubu]

I concur with NHDIESEL! Keep the torque convertor with the tranny.

 

[Bobert]

Good advice, will do.

What about a new filter? Hopefully there isn't to much junk floating around in ther.

Thanks guys.
Robert

 

[BKubu]

I would always change the filter before you install the new tranny. Good luck, Robert!

 

[flewbyu]

Filter is only a few bucks...cheap insurance.

 

[nhdiesel]

Filters are so cheap for this transmission, and it doesn't require any special fluid (unlike some of the new transmissions running $20+/gal. synthetic) there is no reason not to change the fluid and filter on a regular basis.

One thing we used to do at the shop I worked at for customers who used their vehicles very hard...such as a very good postal carrier customer...was to install a drain plug in the transmission pan. Then we would drain and refill every 2 oil changes. Every 30k we'd drop the pan and replace the filter. That postal customer, who had to beat the he.. out of his Jeep Cherokee every day (over 400 stops, then flooring it back out into traffic), got 170k miles out of his original transmission...and even then, the only reason it quit was because a line rusted through in a place we hadn't been able to notice ahead of time, and he tried to keep driving it.

Jim