Mountains Garage: TH400 Lubrication / Dump Valve Issues

[@timtrusty5107]

I am a transmission builder, and I am just starting to see these on some units that people are buying, I have told my customers that limiting fluid to the converter and the cooler is not a great idea, the cooler the trans runs the longer it will last, and just as you said, if you have the right converter, than all that isnt needed, just seems like a bad idea, and you confirmed it showing the parts, thanks,

[@garywoods148]

Excellent explanation on this topic. I have never liked the idea of a dump valve but like you say it's all the craze. You did the best thing for your customer and likely it will work way longer than it did.

[@ls87gbody]

Shawn I saw a video or read somewhere of people with dump valve setups and problems very similar to those had problems with the o ring on the valves inside the dump blocks not holding up to the heat and as a result bypassing charge pressure altogether even with the valve not engaged. ATF transmissions had a similar problem with their o rings on their dump valves and they in turn fixed the problem with a high temp Viton o ring. Just wanted to share. Love your th400 and powerglide tech vids.

[@mountainsgarage]

@@ls87gbody Excellent, Thank you!

[@RyanDunehew]

It’s hard to tell by the video, but by Hughes instructions the cooler return/ lube circuit should be blocked off completely with a plug and a .060 hole drilled from the line pressure pocket/ cavity into the lube circuit. That separates the lube oil circuit and the converter fluid circuit, with constant lube circuit oiling. I can email you the instructions from Hughes it’s an interesting read. I personally have never done one but was curious as to how to accomplish it if ever needed. And thank you for your great videos

[@mountainsgarage]

Yes please, I would like to read them. It must work as I see others doing it. [e-mail] Thanks!

[@stanleysteemr1316]

Excellent observations, Sir. I really enjoy your videos. The TH400 is my preferred-choice Transmission for muscle-car applications.

[@elsdp-4560]

Thank you for sharing. Vickers is not far from me. They have a great reputation for doing really good work. Enjoyed the video.👍

[@petermullin5387]

Even in transmission class (way) back at SMVTI I don’t recall any discussion of lubrication flow in automatic transmissions. Everything was focused on hydraulic pressure flow. Of course the focus was admittedly on stock (or mildly modified - shift kit at most) transmissions. Interesting stuff, always learning.

[@DURRIESVISION]

Another gr8 video👍.... watching from "Down Under - OZ" 🇦🇺

[@th600mike3]

Wow... permanently bridge the converter out and in??? That's actually batshit crazy 😂

[@thomasryan2222]

I was guessing when I seen the title that they put a late model 4L80 center support with the cooler port wide open in..my bane is my carry out unit put into a vehicle that has a plugged oil cooler and worked great for a week...seen it at least 10 times in 30 years you can always tell by the smell as well as the black oil

[@BigFun4Life]

As always a awesome informative video..Thanks again for sharing your knowledge Shawn…

[@jimessex6907]

I’m really considering going to a sfi case. Can you cover what needs to be done to switch from the stock case to the sfi? Like if there is specially parts specific to the sfi case, or anything else you can think of.

[@KarKamp]

Really want to see ya break down everything about internal/external dump valve’s and their supporting modifications.. The dump valves aren’t solely used for get’n up on the chip their also used for a type of traction control/ wheel speed on no prep surfaces, and you don’t have to specify the term “guys” if that’s going to be a serious thing in the future I won’t be around for it…

[@mountainsgarage]

I always respected Barry Meguiar from Meguiar’s Car Care explaining that Car Guy is a non gender term to make sure everyone felt involved. It had nothing to do with the crazy stuff in the world today, just car folks.

[@javierzapata92]

Mountain garage! Are all th400 the same? I'm trying to replace mine ( 1988 chevy c3500 auto 2wd) the only one I can find comes from a 1993

[@mountainsgarage]

They come in different output shaft lengths and spline count. But if you are talking a 1988 R3500 and a 1993 R3500 then you might get lucky.

[@javierzapata92]

And how do I find that information out? I know the engine was replaced 10 years ago with a crate motor( 7.4l) and it looks like the transmission had been rebuilt

[@javierzapata92]

@@mountainsgarage I'm thinking of rebuilding itmyself. I'm not a mechanic but I've work on cars all my life. Just never rebuilt one

[@JoseSantos-hc4kg]

Looks like a TSI case

[@mountainsgarage]

It is, good eye.