Turbo 400 doesn't upshift

[AZRodDave]

Confusion abounds!

on the passenger side of the trans should be two cooler line fittings...might be that they plugged the fittings with pipe plugs or something...either way, that 400 runs pretty hot...it needs those cooler lines badly or it will overheat quickly...as do all auto transmissions....

Now as for this booster....did you say the brake booster was full of fluid? 4 quarts in the pan? Is that an estimate or how did you determine that? Normally you'll get about 5 or 6 qts out of the pan when you drop it...some could drain back out of converter but normally if you do a drain refill it's about 6 qts...

There is only one vacuum line running to the trans...for the Modulator...there is no "booster" on the trans....just the vacuum line to the mod, the electrical plug for the detent (kick down) and the speedo cable...are you sure it's a 400? Does the pan have two large dimples in it and is it an odd shape...like not square...?

I guess I'm just confused....pics would help but honestly, a couple of quarts down might make it slip or engage slowly, but normally would not make it totally inop...Was the fluid dark? Also, did the fluid smell burned? I compare the smell of burned trans fluid to burnt bologna...but that's me...guess we need a bit more info...

The pan is an odd shape, so yes a 400. The original fluid that came out was brownish and smelled burnt. I had put in a couple quarts, but no change in the slow engage after putting it in gear, so I drained it and went with fresh. I'm guessing I got about 3 or 4 quarts in the drain pan based on former experience. I put 4 quarts in, then found out it took 6, so added two more. Might try another if you think that might help?

No fluid in the brake booster. Not sure where that idea came from, but someone mentioned it, so of course I went with it. The brakes are fine and working great!

The brake booster and trans vacuum lines formerly shared a t-connection on the manifold. No longer. They each have a separate spot. Hope this helps to clarify things and not mud the waters further?

Sorry for being such an inexperienced technologist...

 

[Yankee Transplant]

if the fluid stunk and there are no lines going to a cooler or radiator the trans is shot (burnt up) as they said its got to have the fluid cooled down or it will fry the trans.

 

[AZRodDave]

Kinda what I figured.

if the fluid stunk and there are no lines going to a cooler or radiator the trans is shot (burnt up) as they said its got to have the fluid cooled down or it will fry the trans.

Most likely scenario, as much as it hurts to hear. Okay then, plan B...

 

[Yankee Transplant]

put your hands on the trans fittings to be sure they dont have lines that lead someplace else to a cooler .. if its plugged off or lines bent and crimped off he got you ,, sorry there are still p.o.s. people out there that will do that ..
where is the fluid level on the dipstick ? if its full dont add no more ..

 

[AZRodDave]

I will look for those next time underneath, YT, and will get some pics. Thanks!

Wanted to move the truck today and tried reverse and it actually worked! I am thinking low on fluid, so will get a couple quarts and some Lucas and see if it helps.

 

[AZRodDave]

Reverse worked again this morning, even though it was a bit slow to engage. FOUND cooling lines, and they are hooked up, though it is a kluge of short metal lines and hose. Will clean that up one day. Put in Lucas Conditioner and will see how that does. It would be great if that $12.99 investment saves me. I am such a 'tard sometimes ...

 

[tmgant]

You said you drained the fluid, but did you not change the filter? Some 400's have a brass filter, but most have a Dacron filter that over time will plug up just being in trans fluid. Tobby

 

[Yankee Transplant]

I had a t-65 in a javelin and the filter was so rotten it sucked a hole in it and I was running it without the filter for a while I guess .. The car had sit for a while and the filter clogged and when I started to run it ,,, it just sucked it right up in there ...it was a screen type filter ..

 

[AZRodDave]

Reverse or no reverse ...

You said you drained the fluid, but did you not change the filter? Some 400's have a brass filter, but most have a Dacron filter that over time will plug up just being in trans fluid. Tobby

No, I didn't change the filter. The pan has a drain plug on it, so I was lazy and just drained and filled and filled some more. Should probably change all the maintenance parts on it before giving up. Thanks for the advice, guys!

The Lucas treatment seems to be working, as it is shifting smooth and at a lot lower revs than before. Yesterday, reverse did not work, but I wanted to move the truck today, and it was working fine. [S Still a bit slow to engage, but that delay is getting shorter. Might be hope for this thing yet! I can't tell you how close I was to pulling that engine and trans out and selling it as a roller...

 

[sgtpontiac]

AZ....I've seen the filter clogged, the pickup tubes fall off

or the oring seal between the case and the pickup tube either leak or be left out....all would cause you fluid starvation issue, slow engage and slipping....real easy way to test would be to overfill the trans by a quart or so and see if the problems continue....this would raise the fluid level above the pickup tube seal and or make up for the tube falling off with the filter...I'd pull the pan to check both...small shoulder bolt holds the filter in place and the pickup tube seals into a rubber seal on the filter and an Oring seal where the tube goes into the case...when I rebuilt them I double up on the upper orings on the tube to make sure the tube seals 100%..as it is normally above the fluid level line....but that's just me...
I wouldn't suggest driving it for any distance overfilled but it would eliminate the filter and pickup tube and oring seal from the equation...jmho...
Ultimately a pressure test would be the simplest as it would indicate fluid pressure as low from any of the above maladies you have.....

 

[AZRodDave]

When I first got this truck it didn't have the fill tube in it, just a piece of one with a rag stuffed in it. I drove it home that way, about 25 miles, then put a good one in from a TH350. From what I could find, they should be the same(?). I think I have put another 20 miles testing on it, underfilled and maybe overfilled this time. Going to try it out again tomorrow and will let it warm up and check it. Seems like it was low when I put the Lucas in, so added another quart and it was just over the full line (warm and running).

Sure wish some of you experts lived closer!

 

[studebaker59]

the dip sticks are not the same between 350 and 400 transmissions.

 

[AZRodDave]

the dip sticks are not the same between 350 and 400 transmissions.

Oh, okay. I assumed that because there was a chrome replacement at a parts store that said it fit both. Thanks.

 

[BlueNorther]

the fitment of the dipsticks on th350 and th400 are the same.

what you have to do is be sure to use a matched set of tube and dipstick.

there are around 5 or 6 different lengths available, and as long as you buy them as a matched pair, you should get proper level readings.

 

[AZRodDave]

the fitment of the dipsticks on th350 and th400 are the same.

what you have to do is be sure to use a matched set of tube and dipstick.

there are around 5 or 6 different lengths available, and as long as you buy them as a matched pair, you should get proper level readings.

Okay, thanks. Going to put insurance on this thing and drive it a while and see what happens. If it blows, then I'll get a refund... on the insurance, that is.