Trans leak

[JOJABOY]

TH400 was peeing on the street. (Other Chevy's get the garage and driveway). So.......I broke down and replaced the pan seal. It wasn't sludgey at all and no metal shavings. Now, skip a head three weeks to the present. Yup, you guessed it....5 inch circle directly under the tail shaft.

Delima.....

Pull drive shaft and replace another seal on what seems to be a great TH400? Or throw a pan under it for a few months as to scrounge a couple thousand and go for a 700r4 swap? Keeping in mind I have a 72 Dana 60 w/ 4.10:1. TH400 turn 3000+ at 65mph and I want a 4 gear bad.
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[Mister-B]

Originally Posted by JOJABOY

TH400 was peeing on the street. (Other Chevy's get the garage and driveway). So.......I broke down and replaced the pan seal. It wasn't sludgey at all and no metal shavings. Now, skip a head three weeks to the present. Yup, you guessed it....5 inch circle directly under the tail shaft.

Delima.....

Pull drive shaft and replace another seal on what seems to be a great TH400? Or throw a pan under it for a few months as to scrounge a couple thousand and go for a 700r4 swap? Keeping in mind I have a 72 Dana 60 w/ 4.10:1. TH400 turn 3000+ at 65mph and I want a 4 gear bad.
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Well, this probably isn't the "correct" way, but it might buy you time. I had a small tranny leak, and decided to run a bottle of Lucas tranny fix. It definitely took care of my leak, and that was like 5 months ago
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[JOJABOY]

I'm definitely going to throw some Lucas down the tube. I think I'm just looking for someone to push me over the edge to go and do the trans swap. LOL

[1972SUPERSB]

Originally Posted by JOJABOY

I'm definitely going to throw some Lucas down the tube. I think I'm just looking for someone to push me over the edge to go and do the trans swap. LOL

I have a similar leak and think its coming from the front seal. I may try Lucas trans fix also. I also want to have a 700R4 badly too!
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[JOJABOY]

I'm going to call around tomorrow. I want to see if I can find a built 700r4, installed to include torque converter, driveshaft, TV cable, lockup and cooler for under $2000.

[Mister-B]

I'm not much of an additive guy, but I'll be damned if this stuff didn't work


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[1972SUPERSB]

I've had 2 700R4 transmissions in my other trucks. They were a 84 and 87 short bed trucks. Bought mine built and ready to go. I installed myself. I will use the same company again this time around for my 72.
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[jocko]

recommend bowtie overdrives up in Hesperia http://www.bowtieoverdrives.com/index.shtml
Trans will be under $2000, with the other stuff you mentioned, $2K will be ball park.
Have you considered a 2004R? That is the route I plan to eventually go. If you have a C20, am guessing you have a 4.10-ish rear end? Think "useful 1st gear final drive coupled to a 4.10" and the 2004R might be a little more streetable - and either can be built to be sturdy for a 3/4 ton truck.
Here's what I'm talkin about (if you have a different rear gear, let me know and I can post that):
(Don't get me wrong, 700R4 is a great route also - but less deep 1st and slightly more o/d exists in the 2004R, that's all)

[JOJABOY]

I have considered the 200-4r. It's practically the same length of the TH400. No real drive shaft work. Only have to swap out the slip yokes. They just seem to be harder to come by. Most are BOP bolt pattern and built for 3800 engines. I am looking to get trans and installation for $2k. Bowtieoverdrives wants that just for the transmission itself.

[jocko]

actually, their level 1 2004R is $1195 and their level 2 is $1395. Not bad. I'd opt for the level 2. Level 3 is more of a race trans. 2 is just beefed up with some stronger parts.

[jocko]

Oops - my bad - sorry about that - missed that you wanted installation included. You are correct, price would be higher. I'm on the fence if I will install my own - prefer to install it myself (somewhat enjoy transmission work, strangely) but it voids the warranty if I don't take it to them to check line pressure (i.e. on a trailer) before I drive it if I install it myself. So if I'd have to take it there to keep the warranty valid, I might as well have them do it, as much as it pains me. Haven't decided yet though. Won't be living here forever, so the warranty may be worthless to me. Just want to make sure I have the TV set correctly so I don't fry it.

[JOJABOY]

Originally Posted by jocko

Oops - my bad - sorry about that - missed that you wanted installation included. You are correct, price would be higher.

No, that's ok. Believe me I have checked with them. They are QUALITY.

There is no shortage of transmission shops here in Los Angeles. I may need an interpreter to get the price I need though.

[1972SUPERSB]

I set both of my TV cables on the ones I installed. Never had a problem. Just make sure and spend the extra money for the correct carb bracket so everything lines up with the TV cable and carb linkage
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[Stocker]

It's dripping off the tailshaft, but maybe the leak is somewhere else. ATF is very thin, especially when hot, and will travel to a low spot and drip off there. Before you replace the rear seal -- or swap out the trans -- try to pinpoint the leak. With luck, it could be something as minor as the dipstick o-ring.

[JOJABOY]

Originally Posted by 1972SUPERSB

I set both of my TV cables on the ones I installed. Never had a problem. Just make sure and spend the extra money for the correct carb bracket so everything lines up with the TV cable and carb linkage
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I'm sure I could do most of it myself. I do kinda have a Marine Corps Motor Pool at my disposal. I would have to have someone shorten my drive shaft though.

I just bought a 72 style accelerator pedal and one of the LFD cable linkage for my throttle. I have a 69 block with a 74 Corvette carb. (Don't know how or why) So, I would have to figure out the TV cable part.

[JOJABOY]

Originally Posted by Stocker

It's dripping off the tailshaft, but maybe the leak is somewhere else. ATF is very thin, especially when hot, and will travel to a low spot and drip off there. Before you replace the rear seal -- or swap out the trans -- try to pinpoint the leak. With luck, it could be something as minor as the dipstick o-ring.

Your right. Could be from speedo cable. I pulled it when I did the trans pan to lube it. could be just running down to the seem where the tail piece meets the trans body. I should look at that in the morning.

Keep messing around Stocker and you will talk me into keeping the TH400. Always has been a favorite transmission. They don't seem to break easy. But if I kept it.....I would want to go with a higher rearend gear.

[leddzepp]

If it is the rear seal, replacement is easy as well. Since you have a th400, you have a slip yoke that slides right off. Use a flat blade screwdriver to pry the seal off as shown below, and tap a new one in place. Check the yoke for a groove worn into it while you have it out.
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[Stocker]

Originally Posted by JOJABOY

Keep messing around Stocker and you will talk me into keeping the TH400. Always has been a favorite transmission. They don't seem to break easy. But if I kept it.....I would want to go with a higher rearend gear.

Hehehee just trying to save you some money & trouble.... of course that won't work if you have to change the diff gearing.

I've only had one TH400, a long time ago in a '69 El Camino. It got beat on pretty hard at times, didn't break the trans but I did manage to twist the output shaft. Dumb kids anyway....

[Tx Firefighter]

Rear trans seal for a Turbo 400 is NATIONAL Part # 7038SA. It will run you about 5 bucks from a parts store.

The fellow above showed a nice diagram of how to change it.

[JOJABOY]

My big debate with myself has been keep the TH400 and swap to a 3.54 posi
Or...New 700r4 and keep 4.10's in the Dana 60. Both probably cost $1500-$2000
(I think)