Tranny troubles...

[jmacintosh]

I just had a holley carb installed on my truck. The tranny had been slipping  very slightly in the past..normally a fluid check would do the trick. The carb required an adapter which set it up an inch higher, and now I am wondering if the detent cable needs to be changed, or if there is another setting I am missing.

When the tranny is cold, it hangs and slips going from first to second gear. I have to mash the pedal, get the truck up to almost 30 in 1st gear before she drops in second. This gets better as the tranny warms up, but it never fully goes away. Tried several adjustments with the t/v (detent) cable setting, and it doesn't really change anything. Once up to speed, it won't kick down when I mash the gas, like when I am going up hill. I expect it to drop a gear, but it won't. And it feels bogged down, like it is losing power no matter how hard I mash it.

My tranny is supposedly a 3 speed w/ overdrive...400 I believe. So when it shifts while cold at say 30 mph, when it warms up it shifts around 20 mph.

[Blazin]

TH 400 only had 3 gears. Your trans is a 700R4 if it has a detent cable and overdrive. Its bee a while but I think you adjust the cable by losening the adjustment, open the throttle all the way, and tighten the adjustment.

[cooltoolguy]

there should be a "d" shaped button on  clip where it hooks to the carb.   push button in and then while holding same open the carb to WOT and release clip. that is your initail adjustment. take it for a ride and if it still needs adjustment only move the cable one click at a time.  it should make the first shift at around 20 mph.   also make sure you have the proper linkage adapter for your carb.  PS. I put a 700 in my truck last year from a salvage yard (freebie) and it always shifted crappy 1-2 2-3 shift and a lonng lag for a passing gear shift. I brought it to the trans guy last week since its out of the truck for the lt1 swap.  the whole thing was smoked inside, complete rebuild with all new clutches and band plus a new valve body and corvette servo. 1200.00 later ouch!  

[jmacintosh]

WOT = Wide Open Throttle?

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[123 pugsy]

You need an adaptor for your Holley carb. DO NOT drive it the way it is .I also need one for my Edelbrock.Tried making one but its a pain.www.transmissioncenter.net/SwapInformation.htm

[123 pugsy]

I ordered the adaptor today.Will update later with some pics and performance results.

[jmacintosh]

By all means let me know how you make out.

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[VileZambonie]

An improperly adjusted 700R4 TV cable = burnt clutches. Depress the lock button on the TV cable and press the plunger all the way back toward the firewall then inside the vehicle depress the throttle all the way to the floor. (engine off) There is your initial adjustment

[123 pugsy]

Only works on stock carbs.

[VileZambonie]

What only works on stock carbs?

The reason I said to do this inside of the vehicle rather than at the carb is it will actually give you a better initial adjustment reagrdless of what carburetor you have. Until you have the correct linkage do this or you will have low TV pressure which = low main line pressure in this trans and you will burn it up.

[123 pugsy]

I have an Edelbrock carb.When I set the initial setting as described,the engine surges on 2-3 shift.I believe the Edelbrock and Holley carbs have a totally different amount of total pull on the TV cable thus requiring the adaptor for geometry correction.You can set the initial setting as per Vile ,but if it doesn't work properly....DO NOT DRIVE IT LIKE THAT!!!

[jmacintosh]

After speaking with a number of people locally. It has come down to 3 things...

Bad Torque Converter
Bad Clutch
Incorrect valve body installed by previous owner. (Who had a camper on the back by the way)

Any adjustment of the TV cable has produced the same result. There were a couple of things at work here, and I would guess that the problems were probably there before, but are now manifesting themselves because of the engine work that has been done to this point.

Before the tranny troubles, I would experience a little slip from 1-2. Fluid check would normally help alleviate it. Once I decided to work on the motor a little, I then realized I was running on 7 cylinders, or just has really bad detonation on the number 4 cylinder. When pulled, that plug looked like it had a bunch of junk on the end of it, and the insulation around the electrode was broken off.

Since then...
Valve adjustment
New Plugs (same heat range)
New Wires
New Distributor (Accel 14k volt)
New Holley 650 cfm spread bore 4 bbl carb including bracket to level the pull from the TV and throttle cables.
New transmission fluid and filter.

Now we have a lot more power, and the  same, already tiring tranny. It is a 700r4 3 spd w/ OD. Upon pulling the pan, we had metal floating around...not  a good sign.

No matter where the TV cable is adjusted, it won't drop down a gear when you floor it at any speed...AND...It will slip between all gears...AND...never go into overdrive.

When cold the tranny will shift...
1-2 30-35 mph
2-3 50-55 mph
no other shifts while on highway as far up as 70 mph

Once warmed up the tranny will shift...
1-2 20-25 mph
2-3 45-50 mph
no other shifts while on highway as far up as 70 mph

When I am on my way home from work the tranny just starts getting warm, and there is a long hill. The tranny will not get the truck up to 65 mph. Once it makes that 2-3 shift around 55 mph, You can hear it slipping and shuddering up the hill. Mash the pedal...it slips, try to back off the pedal to let the tranny grab onto 3rd gear, and you slow down considerably. Of course you can't get back on the gas again because it will start to shudder.

I was asked if the guy who owned the truck before did any towing. He did have a harness of the back for a trailer, and that bar across the bottom of the truck for a camper he had. There was also the possibility that this guy put in a valve body more suited for towing, which would effectively remove the overdrive, and leave you with 3 gears.

Also, it would appear the torque lockout wiring harness has become dislodged from it's socket on the tranny. Which for however long, has now increased the pressure inside the tranny, and the torque converter, possibly killing the torque converter.

So...I am looking at a rebuild, and set everything back the way it should be...including the torque converter, clutch pack, and whatever else I'm gonna need.

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[VileZambonie]

Rebuild the trans. Perform all of the valve body, seperator plate, pump, servo, PR valve updates. Replace the torque converter and when you set it up make sure you set the TV cable properly. Better to be a little tight initially too on the TV adjust.

There are many updates on the 700R4 make sure you do all of them otherwise you will have a new weak transmission

[jmacintosh]

Just spoke with the garage. The tranny is going to handed over to a specialist who is aware of the updates. I trust that they know what to do. They haven't let me down so far.

With the amount of work that has been done so far, it will be interesting to see just how much power makes it to the wheels after the tranny is done.

1986 Chevy K-10 Silverado 350 SB
1984 Chevy C-10 Custom Deluxe 350 SB

[123 pugsy]

This is what the geometry correction bracket looks like for an Edelbrock.Holley should be similar.I finally got it installed and I have real good shifts now without worring about cooking it prematurely.



Had a homemade bracket on it but wasn't a 100% sure if it was good so I ordered one.Wouldn't you know ,when I got it ,mine was almost identical.Just a hair off.