[ponyakr]

The dipstick tube in my TH400 leaks out fluid, when engine is not running.

Here's the history: I decided to check the fluid level. First checked it before starting engine. It showed above the full mark on the stick. But, I've always read that it must be checked while the engine is running and the fluid is warm. So, I checked it that way. There was no fluid showing on the stick, at all. I added a quart, which just barely showed on the stick. It took aprox 2 1/2 quarts to get up close to the full mark.

So, I assumed that the guy who installed it had just not put in enuff fluid. But, the next day, I noticed a puddle of fluid under the car. I put a catch pan under it. Over the next couple of weeks it appeared to have leaked out just about all the fluid I'd put in it.

I assume it has the correct dipstick for the tube. I was gonna pull the tube and check the o-ring & groove, as well as the length of the stick. But, the bolt that attaches the tube to the bell housing is too close to the firewall to remove. So, I'll either have to move the engine/trans forward, or just cut the tube lose from the mounting bracket.

Anyhow, I'm considering just replacing the tube & stick. I've seen quite a few stock tubes which cracked in the O-ring groove & caused a leak. So, I'm considering an upgrade. One I'm considering is this TCI, which appears to have a much better sealing system than the stock, single rubber O-ring. I think they are called "top hat" seals.

https://www.summitracing.com/parts/tci-743803/overview/

But, the description says it is not recommended for tight clearance apps.

"...These are not recommended for vehicles with minimal clearance between the bellhousing and firewall or transmission tunnel..."

My '68 Bird looks to have only "minimal clearance". So, my question is: have any of you guys used one of these in a '68 Bird ?

I'm also considering one of the cheap flexible tube models, which attaches to the firewall. But, it seems to me that if it has a solid attachment, the engine movement & vibration would make that type tube not the best choice. Anybody use one of these firewall mounted tubes ?

They appear to have 2 rubber O-rings, instead of just 1. So, I assume they would seal better than a stock type tube. There are some models that bolt to a Chevy bellhousing. But I haven't seen any that will bolt to a Pontiac bell. So, a question is, if I decide to try one of the flex tube models, would it be best to try to rig up some sort of a block or bellhousing attachment for it ? Or, do some of you guys know of a reasonably priced flex tube that is made for BOP engines ? I found some Lokar tubes, for what I consider a ridiculous price. Don't know if they are any better than the cheap ones or not. Not gonna pay $100 for a dipstick/tube.

I only wanna buy once, and not have to experiment, to find one that works.
Any advice on a positive solution for my problem ?

http://www.ebay.com/itm/STAINLESS-FL...X-DlMg&vxp=mtr

http://www.ebay.com/itm/GM-Turbo-350...3D272286553265

http://www.ebay.com/itm/Lokar-Hi-Tec...3D200720316647

[Cliff R]

The stock tube can be converted to the multiple lip seal set-up. We do this to all TH350 and TH400 transmissions built here.

The modification is nothing more than cutting the tube and MIG welding or brazing on a new end that accepts the multiple lip seal......Cliff

[grivera]

Does it have the seal that looks like a top-hat or an o-ring? The top-hat seals are great.

[ponyakr]

" The stock tube can be converted to the multiple lip seal...cutting the tube and MIG welding or brazing on a new end that accepts the multiple lip seal..."



Thanks for the info !

But I don't do any MIG welding, and can't make one. Do you sell the tubes with this mod ? If so, what would be the shipped price ?

[ponyakr]

Originally Posted by grivera

Does it have the seal that looks like a top-hat or an o-ring? The top-hat seals are great.

Yeah, from what I've read online, the top hats provide the best seal. Mine is a 40+ year old tube, with a single rubber O-ring.

[b-man]

Never give up your original auto trans dipstick tube, that tube is the only tube configuration that will fit your application. The aftermarket 'replacements' are a joke and I'd be surprised if they would fit any car with a firewall. The factory tubes are all very application-specific and there are few if any substitutes that will work.

Find a local welding shop to do the welding, or mail it out to someone who can add the new lip seal end to it.

[ponyakr]

"...Find a local welding shop to do the welding, or mail it out to someone who can add the new lip seal end to it. "


I have no idea what size or kind of tubing needs to be added.

If this is such an easy & common mod, there should be some Pontiac guys here who have these for sale, for a reasonable price. There are certainly plenty of old Birds out there that could use one.

[b-man]

Find a later style GM dipstick tube that uses the improved lip seal.

Cut off the part that accepts the lip seal at the very end of the tube. Discard the rest of the tube, you only need the bottom end of it.

Carefully measure yours and cut it so it will end up same length as before, where it seals to the trans case. Cut and fit and have it welded up by someone who's not a hack. This is what I'll do with my TH400 tube and stick that I found fits my '64 Le Mans that never came with a TH400, the tube/stick assembly that works came from a '69 GP.

It's hard enough to maintain proper identification of all the tubes one might have in a parts collection. Having a variety of them properly identified, already modded and waiting for sale really isn't practical from a business standpoint.

Modding your own isn't that difficult and is practical because you already know it's made to fit your particular car and trans.

[ponyakr]

"...Find a later style GM dipstick tube that uses the improved lip seal..."

OK, but I've never even seen a tube with the top hat seal. So, exactly what years & trans types came with one of these tubes that I need ?

Maybe I just need to ask my local trans man, who is also a Pontiac guy. I reckin if you make a living building transmissions, you should know about dipstick options, huh ? Maybe he has done the mod ya'll describe.

Just thought maybe as many Pontiac guys as there are here, some would have used some of the ones I mentioned, and could relate their experience with it.

But, if having my tube modified is the ONLY way to stop the leak, I reckin I'll go that way. Gotta keep the fluid in the trans.

[ponjohn]

I used a Lokar tube.

[b-man]

Originally Posted by ponjohn

I used a Lokar tube.

How well did it work?

Were you able to add fluid easily with it?

[ponjohn]

Originally Posted by b-man

How well did it work?

Were you able to add fluid easily with it?

I liked it. Had no choice, the x-bodies that had Pontiac engines didn't come with a t400.

It came with a fitting that went in place of the dipstick to fill. I just left it in the glove box.

Very good quality and no leaks.

[b-man]

The reason I asked was because I'd always read that it takes an eternity to fill the trans due to the small ID of the Lokar tube.

Good chance that a first-gen F-body TH400 dipstick tube would have fit your X-body Ventura.

[ponjohn]

Originally Posted by b-man

The reason I asked was because I'd always read that it takes an eternity to fill the trans due to the small ID of the Lokar tube.

Good chance that a first-gen F-body TH400 dipstick tube would have fit your X-body Ventura.

You're probably right.

I don't know what body the tube came off of. I don't recall the exact problem other than it had interference.

[lust4speed]

Originally Posted by b-man

The reason I asked was because I'd always read that it takes an eternity to fill the trans due to the small ID of the Lokar tube.

Good chance that a first-gen F-body TH400 dipstick tube would have fit your X-body Ventura.

My son's '68 Firebird had the Lokar tube installed when we purchased the car. Total PITA with the fill being a very slow process. Even with a small funnel pushed into the top and sealed up, the fluid just drips down the 3/8" flexible tube.

Since the fluid didn't leak out of the O-ring when the car was new, then something has changed. Most of the time it is simply an O-ring that is damaged by physical abuse or old age. Before ordering out some questionable space age solution, find a new 0-ring the correct size and lube it up with trans fluid before sliding it in. If you get the tube sideways sliding it in, it will slice and dice the new one.

Don't think anyone mentioned that the excess fluid comes from the torque converter draining down. The converter holds a lot of oil, and it drains out over several days back into the pan. If a car is driven every day, only some of the oil comes out of the converter, but give it a week and the oil level will be down to the bottom of the converter output shaft and raise the level in the trans over the top of the hole in the trans body.

Really helps to install the tube on a lift where you can view the tube going in the hole to keep it straight. What you think is a straight shot from above is usually anything but.

I've only used a "top hat" seal on my 200-4R trans that had the same diameter hole in the trans, but has a smaller dipstick tube. I can't see any way that you could get both the 1" long grommet and the standard 400 tube in the hole.

[ErikW]

I use this one in almost every Pontiac build I do.
https://www.summitracing.com/parts/ati-406491

But it looks to be the same as the TCI unit. The Lokar one is a joke and a pain in the arse. Try the mod that the others have suggested. Any GM tube from the junkyard with have the same end on it, FWD or RWD on vehicles dating back to about 87. They used that same grommet to seal it into the case on just about all transmissions and transaxles

[Grand73Am]

Originally Posted by lust4speed

I've only used a "top hat" seal on my 200-4R trans that had the same diameter hole in the trans, but has a smaller dipstick tube. I can't see any way that you could get both the 1" long grommet and the standard 400 tube in the hole.

You can't use the regular o-ring dipstick tube with the "top hat" style seal. Won't fit into the seal. The dipstick tube that uses the top hat seal is narrowed down on the bottom end to be able to fit into the top hat seal. That's why it was written above that if he wanted to use the better top hat seal with his original tube, he'd have to cut off the bottom of his original tube and weld on the bottom of a top hat seal style tube.

[Grand73Am]

I've used 4 or 5 of the Lokars flexible dipstick tubes on Classic Chevy resto-mods in the past with no problem at all. Worked very well for me and had no problem filling the trans with fluid. It was slower to fill but it was no big deal to me. I attached the upper end to a convenient place on the firewall. The tube is flexible, so if you leave a little slack, there's no problem with engine/trans movement. Good solution when space behind the engine is limited. And they never leaked.

[ponyakr]

Originally Posted by ErikW

I use this one in almost every Pontiac build I do.
https://www.summitracing.com/parts/ati-406491

But it looks to be the same as the TCI unit.

So, my question is: Have you used this tube in a 1st gen Bird ???

I assume this tube may be the same as the TCI & ATI.

http://www.ebay.com/itm/Allstar-Perf...-/302117160861

Also, what about the possibility of successfully bending a tube slightly, for clearance ?

[Cliff R]

+2 on keeping the original tube and modifying it for the multiple lip seal. They will NOT leak and you keep the original fit. The conversion is pretty easy, it can even be epoxied in place but I prefer MIG or brazing it......Cliff