I have a 700R4 Raptor trans with internal TCC lockup in 4th gear only. Recently when in 4th & rolling on the throtle easy, a shuddering occurs. Seems to be either 4th gear is not holding or the TCC is slipping. 1-2 & 2-3 shifts are firm & still spin the tires on full throttle. Anyone experience this? Hoping it may be as simple as replacing the 4th gear band or the converter. I am also considering a T56 swap. How well do the T56s hold up with a 500 hp 383 plus an occasional trip to the drag strip?

 

the lock-up function has nothing to do with the 2/4 band. lock-up is valve body/pump/solenoid/torque converter related. how fast are you going when this occurs?if it is under 60mph, that could be part of the problem. if you aren't doing more than 55-60 mph, i would leave the shifter in the drive position.

 

I realize the TCC has nothing mechanically to do with 2-4 band. But the TCC is set to only lockup in 4th gear & was trying to isolate the cause. I did a little bit of diagnostic work last night & disconnected the TCC power. It still shudders in 4th gear & also slips a little in 2nd, so it not the TCC. Driving in "D" is only temp fix. The trans needs to be freshened up.

 

T56 will do a hell of a lot better on 500hp than a built 700R4 will. I know a couple guys running 9s/10s on their stock T56s...I also know a guy who blew is apart running 10s they're a better transmission and a ****load more fun

 

I am taking a serious look at a TKO 600. People say a T56 will hold & people said the Raptor would hold too, well. According to Tremec's website the T56 is rated to 450ft lb torque the TKO 600 is 600. Don't really need the 6th gear.

 

How much is that TKO 600?


The borg warner T56 is rated for 450 ftlb the tremec is significantly lower.

 

Which Tremec? They make about 25 varieties, including the T56. The Viper spec T56 is rated at 550 ft lbs. Borg Warner was sold to Tremec about ten years ago. The TKO 600 is 600 ft lbs torque & 650 hp. I was just quoted $1650 for the GM TKO 600.

 

"It still shudders in 4th gear & also slips a little in 2nd" The 2-4 band is the problem here. It will take the reverse/input drum out when this happens. Both will need to be replaced.

 

Yes thanks, I pretty much figured that. Do you think the 3-4 clutch pack should get replaced or anything else? I realize it will have to be torn down & inspected, just trying to get a handle on the cost of this to see if it's worth it to fix it to sell it to help pay for the TKO conversion or dump it as a core.

 

why would that be cheaper than a T5 if its a better transmission?

 

Used T5s go for around $500. Have not seen any new ones for sale. G-Force T5s are over $2K & not worth it in my opinion. The low price I got is because I work in wholesale parts distribution & one of my customers is a Tremec dealer. I have seen them on the internet for $1795.

 

Damn, when I need a new transmission I know where I'm going...holy crap thats cheap. Jegs and Summit both sold T5s just a few years ago they were 2100 to 2400.

 

Ive never been clear on how the TKOs are rated vs. the factory T-56's. i just used 80% of the torque rating that tremec gives to make my choice. I cant see it being much weaker, especially after having opened it up to fix a stuck shift fork. The parts inside are like 3x the size of what was used in the T-5. Cant wait to get around to trying it.

 

hey, you said earlier to keep it in regular drive if under 55 mph. why do you say this...i never heard about it before. could be how i messed up my tranny.

 

That's pure nonsense. You can drive in OD at any speed.

 

ok because i noticed it would act weird right around the shift speed. like not making up its mind, or not downshifting and bumping a little bit.

 

Sounds like my problem, the 2-4 band is not holding.

 

actually, sometimes the tranny will "search" when it is at the speed when it would shift into OD. this "searching" is the tranny trying to shift into and out of OD. leaving it in drive prevents this. will not necessarily hurt the tranny, but is annoying to say the least.

 

The searching you speak of is true, but when the trans is going out the shifting starts to get sluggish & feels funny. 4th gear & reverse are usually the first to go.

 

yeah, if you lose 4th and reverse at the same time, you have really got a screwed tranny since they don't even involve the same clutch packs. my tranny has a totally different shift feel if i leave the shifter in "d" at surface street speeds. it just sounds like ZZ4's problem is more "searching" than anythnig else. searching trans. does feel weird.

 

that was just something it was doing. but i lost my upshift. it started in third and wouldnt go into OD. and then when I stopped at a light, it wouldnt go out of first when I moved again. I tried replacing the governor, but no dice. and the old one was broken. and with the new motor and the old tranny I think I need a new better one anyhow. especially with the pre 87 trans. plus a nice new one was on my list anyhow.

 

it was during the searching that the trans decided not to go into od it just didnt go back. it was like 3rd, od, 3rd, revs kept going up. I was like huh thats weird. and then i left the light and it just kept going up up up.

 

yeah, then rick was correct. you just lost your 2/4 band.

 

ARE YOU SERIOUS?! that would restrict me from getting out of first? that would be so cool if that was all. at least i can drive my car until i get the new tranny. please reassure me of this!

 

and i didnt lose reverse.

 

i wouldn'tdrive it around with only first gear. that would be hard on everything.

 

i was like half a mile away from home. after replacing the governor i drove it like 1/4 mile to see if it would work and it did not. but could this be the problem?

 

my opolgoies, i missed the part about the broken govenor. pull the new govenor back out and make sure it is intact. yes, the govenor will keep it from shifting especially if this one broke as well.

 

how could it break upon installation?

 

you said your original governor broke. then you changed it. did the tranny shift after changing the governor? if it did, you have the same problem that caused the original governor to break. unless i'm not following your time line correctly.

stopped shifting.
found broke governor in trans.
replaced governor.
trans shifted a couple of times then quit again?

 

never shifted again after install.

 

ok. that is where i misunderstood you. then yeah, i would say it is the 2/4 band. but it is not a good idea to drive it around in first gear only. that is hard on the motor as well as any parts of the tranny that are still good. it MIGHT shift into 3rd at high rpm's if you are lucky. but that is hard on the tranny as well as motor. not to mention gas mileage.

 

like i said i havent even driven it a mile since it broke like 3 weeks ago.

 

ive been told not to shift into OD till speeds over 45 mph do to low fluid press at low rpms.so yes more then one trans tech has told me that.but take in facts of rear end gears would change all this.myself if im in overdrive and i get under 2000 rpm's i pull it into 3rd.i have been running my 700r4 for 4 years now on the street and track.i have my likes and dislikes of this trans,like having to come off the throtle going into OD cant be nomore then 2/3 on the gas or it red lines on me like there is no gear there.

 

there are kits that can be bought to supplement the shift kit that take care of the wot upshift problem.