[Crawdaddy]

Hrm, where to start... Well, as I'm sure ya'll know, I replaced my transmission because my previous one burned up (see http://www.gmtruckclub.com/forum/showthread.php?t=9192 for more information on that). So, my uncle and I put the new rebuilt transmission in my truck and things started looking up. Before we put the rebuilt tranny into the truck, we filled the torque converter as best we could. I followed the procedure in the haynes manual to readjust the TV cable, in fact, I started from scratch and readjusted the cable 3 times to make sure it's right. From mile 1 with the new transmission it seemed like it shifted a little bit late from 1st to 2nd gear. Well, Friday night I went and picked up a very light 5x8 box trailer. I then loaded it with a fridge and dryer, nothing heavy and towed it around 50 mins away. About halfway through, the transmission seemed like it was shifting later and later for 1-2 and 2-3. It got to the point where it would shift from 1-2 at around 25mph and 2-3 at around 50mph. It barely ever got into 4th gear at all. At that time, I pulled into a gas station and checked the tranny fluid. Well, it was a TINY bit low, so I bought a quart of tranny fluid and filled it up. That didn't help anything. I got the truck home through lots of taking it easy. I did get it into 4th gear on the interstate through lots of coaxing. My buddy who went to school for trannies, but hasn't worked on one in a while, thought it could possibly be either a bad torque converter or a check ball, spring or servo that is dislodged or broken in the valve body. Any ideas as to what's screwed up in the tranny? I'm clueless, but something's messed up.

 

[tbplus10]

That sucks.
I think your buddies got the best diagnosis on this problem.
Did you replace the torque converter with the tranny? Not required but you did have a high mileage drivetrain so it would be recommended.

 

[Crawdaddy]

The torque converter was replaced at the same time as the tranny with a rebuilt torque converter from the same company. Any ideas as to where to start looking? Should I got for the torque converter or valve body first?

 

[tbplus10]

Check the valve body first. It can be accessed by dropping the pan and filter. The Torque convertor requires the trans to be removed.
Also check the vacuum module, I dont think its the problem but it wont hurt to check.
Spray carb/injector cleaner around the vacuum hoses while the engine's running to see if they developed a leak.

 

[Davandy]

It sounds like a vacuum leak :neutral:

 

[Crawdaddy]

the TH700R4 for my year/truck does not have a vacuum modulator, or any modulator for that matter. The only connection that is present from the motor to the tranny is the torque converter and the TV cable.

 

[tbplus10]

Forgot youve got the electronically controlled trans.
Then it's down to the Valve body and the Torque Converter.

 

[ChevyFan]

Sorry to hear you got troubles, that stinks becuase I know you worked hard on this and were looking forward to it. Let us know what you find out.

 

[Crawdaddy]

Tim, I don't know how the hell my tranny knows what to do, it's not computer controlled and it's not vacuum controlled. All the connections that were made to the tranny was the gear selector lever, speed sensor output, reverse gear sensor, tranny cooler lines, dipstick tube, TV cable, torque converter, bolting it to the motor, and that's it. At my first bit of spare time, I'm going to drain the pan and pull the valve body. I need to find a good supplier of all the hard parts in the valve body for a reasonable price. And, I guess while I'm at it, I'm going to get the shift kit I've been wanting to get and add that in. I wonder how much a brand new valve body would be....

 

[Crawdaddy]

OK, after it raining so much for the past 3 days, I finally had time and decent weather to get something done on the truck. I went and readjusted the cable at the throttle body. Well, it seems to drive and shift about as well as when I first replaced the transmission, so that's good. It just still doesn't quite seem to be right yet though. I'm following the adjustment procedure to a Tee as far as I know. I'm considering pulling the motor since it's got near 200K on it and it seems like it's on the decline ever since the tranny died. If I pull the motor, the tranny's coming out with it. Judging from the results I got with the TV cable, I think it's still an adjustment issue. Should I just ignore it for now till I rebuild, or should I fix it now? Any ideas on how to get it right? It seems like it's sooo close, but far enough out to be a pain.... Thanks as always guys!

 

[Crawdaddy]

Friday I went to take it out on another trip up to camp. Since it seemed a little odd that the TV cable got out of adjustment, I took it on a quick trip around the block to check to see if it was acting ok. Well, it wasn't. It's back to not shifting until 25 mph from 1-2. Any ideas before I haul it over to the transmission shop to get them to fix it? This is getting really annoying....

 

[Gmcsuvguy]

Do you have any engine driveability conditions? Is check engine light on? Does speedometer seem acurate?

 

[Crawdaddy]

Other than the engine having to race because the transmission shifting late, the engine has been running well. The idle is the tiniest bit rough, but it's almost non-noticeable. The check engine light is off, but the transmission is not controlled at all by the computer. The speedometer appears to be accurate. If it's off, it's only off by MAYBE 2mph.

 

[Gmcsuvguy]

The transmission shift solenoids, tcc lock-up solenoids are controlled by the computer.

 

[Crawdaddy]

I'm going to take your word for it, considering that I have seen no indications to relate to this. This is a TH700R4/4L60 (NOT 4L60E) transmission that has 2 electrical connectors, one 2-wire connector on the tailshaft for the speedometer/rear-wheel ABS, and another 4-pin with 2-3 wires for the reverse light switch. Unless computer control is being done through 1-2 wires, there is NO computer control of this transmission. Also, if I look up the trouble codes for my truck, there are no trouble codes related to the transmission. According to all the reading I've done, the TH700R4/4L60 transmission only has the TV cable to rely on to determine what's going on outside of the transmission so it can shift properly.

 

[Davandy]

There's a round thing (can't remember the name) on the left side near the tail shaft of the tranny inside are centrifugal weights I’ve been told they manage the shifting maybe you can have a look there its hold on by a spring.:neutral:

 

[larryderouin]

Crawdaddy: Go to this link. It's a 3 page article from Bowtie Overdrives on TV Cables, and how they affect the operation of the 800R4/4L60/200R4. I think you can gather enough info to either fix what you have or have the shop fix it to your satisfaction.

http://www.tvmadeez.com/article/index.php

Larry

 

[Crawdaddy]

Thanks for the link. I think with that information I can proceed forward enough to at least get the transmission acting normal enough to get it to the shop. According to what I read, it appears that the transmission is suffering from "Long Spring Syndrome". I think I'm going to pull the TV cable off from both ends, reattach and reajust it all. I'm also gonna check to make sure my accelerator can still push the TBI wide open. If all else fails, to the transmission shop it goes!

 

[unplugged]

Ouch! Mine started doing the same thing a few days ago. After a recent trip towing a 7000lb trailer the trans started acting up. Reverse was fine, but only L1 worked otherwise. I have neglected recent service since I haven't driven it much.

It broke down 50 miles out of town So I took it to a local quickie lube. (I hate quicky lubes but it was open on a Saturday) I had the fluid flushed and a new filter installed, plus they added Lucas trans conditioner too. Afterwards it wouldn't consistently shift into D or OD so I added Prolong transmission treatment and it improved immediately. It will start from a stop in OD or D and shift normally most of the time. It seems sensitive to throttle position and speed. Sometimes it drops out of gear while in OD or D and it recovers when I shift it to L2.

I've got an appointment later this week at the trans shop to get a diagnosis / estimate.

 

[unplugged]

With all the talk of TV cables I thought I'd take a look under my truck. No TV cable cuz I have a 4L80E. I did find a missing nut on the linkage. I replaced the missing nut and was hoping it would help with my shifting issue, but no luck. Well it's off to the trans shop later this week.