TH-700R4 Thoughts and advice?

[swissarmychainsaw]

I have a 1984 Chevy Silverado, 305 Th-700R4 shortbed 2wd.


I have owned this truck for just under four years and have been struggling with (and paying for) this transmission more than I would like. The truck is really nice, but I need the trans to work better.
(I'll go in to what "not working right" means).

Special Notes:
Accelerator pedal feel is very stiff meaning you have to really press down hard to "give it gas". I'm now wondering if that is related to the Throttle Valve Cable.

Mostly this truck sits around, but I do take it road trips, camping or dirt biking.
So it's either sitting, or on the highway.

Transmission has leaked for years, and with the last trip to the shop I think we finally have it stopped.

Transmission Shifting:

Normal:
Typically shifts early. Driving up a steep hill, it will shift into higher gear, so I have to nearly floor it to just keep it in a lower gear to climb the hill.
It has behaved this way for the 4 years I have owned the truck. (Now I think that this indicates throttle valve issues, since this controls shift points).

Not Normal:
On a road trip to death valley (aka after 6 hours of driving); the transmission started shifting really late. First to second shift would shift only at
high RPMs, and so on. I was able to get it home, as cruising on the freeway was ok, but this was a sudden change and concerned me a lot.
(had transmission serviced, pan gasket replaced, which was leaking) I don't remember what all he did, but I remember that he replaced a broken
plastic gear, which was either orange or green. this was three years ago.
As I recall this helped things for a while, but the trans still leaked, but I believe that the shifting was back to "Normal".
(I must say I took this to a place that specializes in Differentials, they are not a trans specific shop. They got good review on yelp and I like and feel like
I can trust the own/mechanic.)

A year after that…

I took it back to the shop cause it started leaking REALLY badly.
He pulled the transmission and replaced the front pump seal.
This is the point where I likely should have rebuilt the transmission, because pulling it was expensive.
(leak was better, but still there)

A year after that...

I towed a three rail motorcycle trailer (loaded) about 3 hours each way on a weekend. After that:
It started late shifting again, but only for 1st gear. It only wants to shift into 2nd at around 25 mph, where the engine is revving up good, and then it shifts very hard into second.

Back to the shop:
They "serviced the trans" again and replaced the shifter shaft seal (no more leaking!)
Still shifted really late from 1st to 2nd.
I drove it for about 45 mins on the freeway, to a campground let it sit over night, drove 45 mins on the freeway again, and when I got back to town it started shifting "Normal"(see above) again.

I have taken this truck three times to a shop (same one) and each time they have stopped one leak
(and done the services I mentioned above). Front Pump seal, pan, shift seal. The leak seems to have stopped but the trans is not quite right.

I have just started to educate myself on these transmissions which were always a "black box" to me.
The guy at the shop says it's time for a rebuild, an gave estimates for rebuilt trans from $1500 - $2100 installed with varying warranty levels (most expensive was 3 years from Jasper).
So thats $1650 for the Trans plus $3-400 installation.

The reason I don't like the "just rebuild it" strategy is that it does not tell you what is wrong.
The trans *works* it has not failed, and now it is not leaking.
The trans does not slip, and what it does is not shift right. I have this strange feeling in my
gut that I can actually fix this thing.

My current theory is that the Throttle Valve cable, or "throttle valve" is bad.

What about the "Shift Improver Kits" from B&M?

I found this good article on how the Throttle Valves work:
Throttle Valve 101 [http://www.tvmadeez.com/article/index.php]

I hope this long winded post helps to explain where we are and is not just rambling.

I would like advice from 700R4 Gurus here, I feel like it's worth the time and money to fix it right.
Now, if my mechanics would just feel that way!
--Nick

[piecesparts]

Years ago, I put a 700 R4 in my 84 GMC SWB truck. To this day, I am not sorry---the only thing that I would do to upgrade from this would be a six speed manual tranny, but that is actually too pricey, now. I have a fully built 700 with a 2400 stall converter, to support the cam that I have in my stroker engine. The tranny has the heavy duty planetary and sun clutch setup, heavy duty clutches, the upgrade valve body and hardened seperator plates in it. I run down the highway at 2200 to 2500, depending on what my cruising speed is. My rear end gears are 3.73 and my tire size is at 28.5" tall, so I have a little more RPMs than some people would have. I get around 15 MPG from a 400+ HP engine and tranny combination and it can perform with the pony cars surprisingly well. I also have a shift kit from Transgo in the valve body, that was a noticeable change in the shift capabilities.

[mikev]

Originally Posted by piecesparts

Years ago, I put a 700 R4 in my 84 GMC SWB truck. To this day, I am not sorry---the only thing that I would do to upgrade from this would be a six speed manual tranny, but that is actually too pricey, now. I have a fully built 700 with a 2400 stall converter, to support the cam that I have in my stroker engine. The tranny has the heavy duty planetary and sun clutch setup, heavy duty clutches, the upgrade valve body and hardened seperator plates in it. I run down the highway at 2200 to 2500, depending on what my cruising speed is. My rear end gears are 3.73 and my tire size is at 28.5" tall, so I have a little more RPMs than some people would have. I get around 15 MPG from a 400+ HP engine and tranny combination and it can perform with the pony cars surprisingly well. I also have a shift kit from Transgo in the valve body, that was a noticeable change in the shift capabilities.

I want one of those for my 6.2. Hello, 25mpg!

[kalbert]

If you think it's the transmission is original to the truck, replace it. '84 is a bad year, all the early ones are built with weak parts. Later years they refined the design of a lot of parts inside to be stronger.

The best 700 I've ever been near was a fresh rebuild to factory specs, which is pretty much any of them built professionally with any kind of warranty. What made it so good was the TransGo SK700 kit installed in it. This is not a high performance reprogramming kit, it's a bug fix kit. It fixes all the common complaints, and some you maybe never noticed until they were gone. If you've got by some mistake or misfortune the "554" servo piston, replace it with the TransGo 7-2P.

I know this sounds like a commercial, but trust me. The guy at TransGo knows whats going on. On a related note, the 4L60E kit is gold too.

[mooseknuckles]

personally I love the 700r4....but to me yours sounds like its had one too many band aids, I'd start looking for a newer one and have it rebuilt in the meantime....and at a different shop too!...

[kalbert]

Some other things I just thought of....

There may be worn valves or bores in the valve body, pressure regulator, or governor that are causing the valves to get stuck or hang up. You'd have to take it apart to check for this, and at that point you may as well get a different one.

Installing the TransGo kit is not for the faint of heart, it requires lots of patience and some fine tuning to get things exactly right. The instructions are phenomenal though, and you'll have an Associates Degree in 700R4's when you're done.

Two other things I would suggest are an auxiliary cooler for sure, and a torque converter from a 95+ S10 with a 4L60E and a 4.3 V6. I'd advise against a cooler with an external filter, the oil that is cooled is then used for lubrication, and if some how the filter becomes plugged or the bypass valve isn't working or it bursts, you could starve the transmission of lubrication. The torque converter will stall a few hundred RPM higher and wake the motor up and get you going without being ridiculous or overly hard on anything.

[piecesparts]

The 700s have a lot of wear issues in the older ones with the sonnex valves and the seperator plates in the valve body. However, if you are going to go that far, then by all means update the internal clutches and the governor. we built mine to handle hard shifting and weekend torture and I like it. I would also recommend a theavy duty oil pump, since in my time I have broken two pumps and that is the fix for that issue.

[beamn7]

I would have to say that I agree with the overhaul and certainly with the trans-go kit. You can also install the alto red eagle 3-4 clutch pack and a kevlar 2-4 band.
You may want to look for a later model case. Pre-87 case's are weak and 84 may still have the smaller input shaft. 87+ with the aux valve body is the best case, install the above mentioned parts and also certainly upgrade the forward sprag to a 30 element as well as the pump vane and rotor assy to at least a 10 vane if not more (4L65E 13 vane works great), hardened reaction sun shell (aka "the beast") and hardened input housing. The list goes on and on as far as upgrades you can do but these are the bare minimums I would go with and I've built my fair share of 700's while at the dealer level.

As for your original question, the hard pedal certainly usually indicates a bad throttle valve. That can be replaced easy enough during the rebuild process without having to replace the entire valve body. These valve bodies were still cast so they don't wear as easy as the newer alluminum valve bodies we are dealing with today.......

Oh, and I would stay away from Jasper........

My $.02

Best of luck

[kalbert]

Originally Posted by beamn7

As for your original question, the hard pedal certainly usually indicates a bad throttle valve. That can be replaced easy enough during the rebuild process without having to replace the entire valve body. These valve bodies were still cast so they don't wear as easy as the newer alluminum valve bodies we are dealing with today.......

You know you bring up a good point here. Could be just a stuck or sticky TV valve. If I'm not mistaken I think the bore for the TV valve is an aluminum part that is just pinned in, and prone to burrs and cracking.

There is also the possibility that the TV cable is frayed or pinched or otherwise damaged and sticking. have you disconnected the cable from the carb and verified that it moves smooth and consistent?

[swissarmychainsaw]

It's worth double checking but I believe the cable is OK.

So this is my original bench-diagnosis: Throttle valve (or cable).

It seems that the Throttle valve can be replaced without pulling the transmission right? (included in some shift kits)

Is this worth pursuing? The problem with the trans is that it shifts at wrong times.

Thanks for the time everyone.
--Nick

Originally Posted by kalbert

You know you bring up a good point here. Could be just a stuck or sticky TV valve. If I'm not mistaken I think the bore for the TV valve is an aluminum part that is just pinned in, and prone to burrs and cracking.

There is also the possibility that the TV cable is frayed or pinched or otherwise damaged and sticking. have you disconnected the cable from the carb and verified that it moves smooth and consistent?

[Firebirdjones]

Those TV cables do need to be adjusted from time to time. I wouldn't go replacing things just yet until you check the adjustment. Everything you are saying this trans is doing wrong (and stiff throttle) all circles around that TV cable in my mind.

[BigSlicc]

I had a friend with a 700r4 and his TV cable snapped where the cable and the plastic housing meet down by the tranny the cable never broke was just seriously misadjusted it started to shift funny but he kept on driving and totally grenaded his tranny

[crazeetxn]

Could be the TV cable/valve. Had mine rebuilt a couple years ago cause it quit shifting. Still had reverse. About 18 months later, it started shifting really late and ran the RPMs up.

Took it back to the shop. He said the TV cable was stretched out and almost broke. He also rebuilt it again too. Said when I had brought it in, they were given some really bad parts and he didn't want those in the trannys that left his shop. Said he'd had problems with others as well.

Check the TV cable or have the shop check it for you. It's my understanding it's really hard to get them dialed in without a pressure checker.

[swissarmychainsaw]

Anyone recommend a good shop in the Los Angeles area?
(pacific palisades)

It was being perfect so I drove it down
From San Francisco!
About 50 miles from my destination first gear
Started making ugly noises.

Going to bite the bullet and get it done
Down here.
Nick
Posted via Mobile Device

[Firebirdjones]

Wow, that's a rough way to go about it. I don't know anyone in the LA area. Hope it works out for you though.

[Malo83]

I had the 700R4 rebuilt on my 83 by AAMCO back in 87, got the lifetime warranty and it has come in handy, crapped out on me in 99 and was rebuilt again, but this time the dealer gave it his special rebuild with newer heavy duty parts and a shift kit, she's been troublefree since, with the lifetime warranty you take it in once a year to have them check, road test the tranny, no cost to you
http://aamco.com/AAMCO_extended_car-auto_warranty.asp

[swissarmychainsaw]

Well that's what I'm doing. Double A M CO.

They pulled the tranny and said it needs planetary
Gears which he will include at the quoted price.

Guesstimate is:
1300 labor
Transtar kit 350-ish
Torque Converter 300

1950$ includes a one year 12k mile warranty
Which I will likely upgrade.

I also plan to get Lots of details on exactly what
They did.

I don't like doing it like this, but a couple of extra
days with my folks is ok and work is being nice
for the extra time off.

If this gets *really* fixed and I get a warranty
it will be hard to complain.
Oh and I don't have tranny fluid running
down my arms or busted knuckles! LOL
Nick
Posted via Mobile Device

[m00n1957]

700r's built before 87 are a POS.

[Firebirdjones]

Originally Posted by swissarmychainsaw

Well that's what I'm doing. Double A M CO.

They pulled the tranny and said it needs planetary
Gears which he will include at the quoted price.

Guesstimate is:
1300 labor
Transtar kit 350-ish
Torque Converter 300

1950$ includes a one year 12k mile warranty
Which I will likely upgrade.

I also plan to get Lots of details on exactly what
They did.

I don't like doing it like this, but a couple of extra
days with my folks is ok and work is being nice
for the extra time off.

If this gets *really* fixed and I get a warranty
it will be hard to complain.
Oh and I don't have tranny fluid running
down my arms or busted knuckles! LOL
Nick
Posted via Mobile Device

Sounds about normal. Hope it works nice and smooth for you on the drive home.

[kalbert]

It's fun to build your own if you have the time and expertise, but you can't go wrong with a pro built unit. I'd guess those guys have built more 700's than you could shake a stick at. And you can probably shake a stick at a heck of a lot of transmissions!

[SSC's76]

the 700r4 is a good transmission if properly built. the shifting issue with yours is related to heat. either the valve body is not tight possible gasket failure or the case part of the valve body could be warped. its had to say without pulling it apart. either way it needs gone through. 700r4's are kinda crap from the factory pre 88 are the worst of the bunch 88 and up there were several improvements made like an auxiliary valve body and some other improved components. if you get a rebuild try an get an 88 or newer core and have it rebuilt. there were actually 3 different 700r4 transmissions made prior to the 4l60. you don't need all the hardcore parts but most builders will use them rather then the stock parts which drives the rebuild prices up. a transgo shift kit a nice 2000 stall converter and an external cooler will have it shifting perfect and running cool for a long time. I don't suggest jasper I've been to their plant and I've had issues with them for warranty engines not to impressed.

[Desert1957]

Originally Posted by swissarmychainsaw

Well that's what I'm doing. Double A M CO.

They pulled the tranny and said it needs planetary
Gears which he will include at the quoted price.

Guesstimate is:
1300 labor
Transtar kit 350-ish
Torque Converter 300

1950$ includes a one year 12k mile warranty
Which I will likely upgrade.

I also plan to get Lots of details on exactly what
They did.

I don't like doing it like this, but a couple of extra
days with my folks is ok and work is being nice
for the extra time off.

If this gets *really* fixed and I get a warranty
it will be hard to complain.
Oh and I don't have tranny fluid running
down my arms or busted knuckles! LOL
Nick
Posted via Mobile Device

If this is the same shop that has done ALL the prior work, I would go somewhere else.

If you are serious about keeping your truck long term (Like Most of us here) I personally would buy a complete new transmission and converter and install it yourself. You already know how to check the TV cable and adjusted it.

There are numerous companies who have figured out 700R's and will supply you with a Heavy Duty version of what you need , with a warranty.

If you are prepared to spend $2000. anyway , Lose that old core , Too many hands have been in it for it ever to be right.

The sticking throttle problem is most likely the throttle cable itself, they do go bad internally.

Desert

[Desert1957]

Here is just one example of the MANY companies out there selling these transmissions ( I am not advertising for this company) but its an interesting overview of the upgrades to the internal parts they offer.
http://www.performabuilt.com/heavy%2...20700-60E.html

Desert

[swissarmychainsaw]

Well, as I was stuck 400 miles from home, I decided to get the tranny rebuilt at AAMCO and got the one year warranty (transferable).

It was not my *best* option, but it's one I can live with and I got my family home safe and sound.

Thanks to everyone for they help and advice on this project.

Tranny seems to be doing pretty well...
--Nick

[Edahall]

Originally Posted by swissarmychainsaw

Well, as I was stuck 400 miles from home, I decided to get the tranny rebuilt at AAMCO and got the one year warranty (transferable).

It was not my *best* option, but it's one I can live with and I got my family home safe and sound.

Thanks to everyone for they help and advice on this project.

Tranny seems to be doing pretty well...
--Nick

AAMCO

Don't consider this the end of your transmission problems.