DIPSTICK

[Martin N.]

Anyone have the length of a C-3 Turbo 400 trans dipstick? Mine just peeks out at the bottom of the fill tube. Not sure if that's right. THANKS....Marty

[Loren L.]

Re: DIPSTICK

Let's see...C3 takes in 15 years and who knows how many engines...somebody measure them all and provide an "average".....

[Terry M.]

Re: DIPSTICK

You are right Loren, but his Turbo 400 request limits it somewhat more. I don't know if there is a BB v SB difference. Probably someone who is good with a parts book, or parts computer might be able limit our search further.

[Mike E.]

Re: DIPSTICK aka Dennis C.

By the heading, I thought you were looking for Dennis Clark!!

[Joe L.]

Re: DIPSTICK

Terry------

There was no difference between small blocks and big blocks relative to the THM-400 dipstick and tube. However, there were differences over the years of the THM-400 use in Corvettes. There were 2 different dipsticks used over the 1968-73 period, although they are functionally interchangeable. The 72-73 PRODUCTION (which became SERVICE for 68-71) dipstick, GM #1239014, remains available from GM for about 7 bucks, GM list.

The 73-76 dipstick was different. However, it was also used in conjunction with a different tube. The original dipstick is discontinued but its successor, GM #10017293, remains available, also for about 7 bucks, GM list.

Unfortunately, I do not have any specs on the above dipsticks.

No THM-400 was used in Corvettes after 1976.

[Joe L.]

Re: DIPSTICK

Marty-----

Well, with a little more research I may have figured this one out. The 1968-73 THM-400 dipstick tube is 23" long. From what I can determine, the 1968-73 dipstick is 24-1/4" long. For 74-76, I know not.

[Joe L.]

Addendum

Marty-----

Well, I know a little more now. The 74-76 THM-400 dipstick should be 27-5/16" long. I still don't know the length of the tube. Yet.

[Martin N.]

Re: Addendum

SORRY! I'll be more specific in my posts. The info. I'm seeking is regarding to a 1974 Corvette (C-3) with the standard L-48 (350 c.i.) small block engine.
THANK-YOU JOE!....Marty

[Joe L.]

Re: Addendum

Marty-----

Let us know how the length of your dipstick compares to the dimension I provided.

[Martin N.]

Re: Addendum

JOE, I REALLY appreciate your time, I'm glad you got me this measurement. The one I have currently is 26 1/8" long. My trans code is: "74 CK 443" which is correct for my car. So now with this dipstick being over an inch short I can understand why my trans leaks badly, I'm overfilling it and maintaing the improper fluid level. Some time over the years someone has switched out the dipstick (and maybe the tube?). Next question is the proper length of both tube & dipstick. It would be interesting to see if this dipstick is out of a 350 trans. THANKS for all your help Joe....Marty

[Harmon C.]

Re: Addendum

Marty

All turbo 400's that I have owned have leaked some worse than others even if rebuilt. One way to see if your dipstick is too long is let it leak till the trans won't shift and see what your gage reads. With a bad leaker it won't shift when two quarts low but one quart will make it so it can be moved from one garage bay to another.

Lyle

[Joe L.]

Re: Addendum

Marty------

I wouldn't recommend that you necessarily decide that your dipstick is incorrect just because of the variance in the dimension. The 27-5/16" spec that I mentioned is a GM spec. HOWEVER, GM has been known to publish these specs in terms of DEVELOPED LENGTH (developed length is the length the piece would be if all the bends, curves, and "waves" were "flattened out"). I don't THINK that's the case with this GM spec since it would make no sense, at all, to specify length in terms of DEVELOPED length, but that doesn't mean, for sure, that they didn't.

The first thing I would do is to go down and order a GM #10017293. Then, you will know that you will have a correct length dipstick, assuming that the tube is correct. It's much more likely that the dipstick has been replaced than it is that the tube has been changed. The dipstick only costs about $7, GM list, so you won't have a big investment here.

The original tube, GM #340659, is discontinued and I can't find any supercession. However, there may be one. Just ask you dealer to check for supercessions for this number. If there is a supercession, I'd buy it just to confirm that the tube you have now is correct. While it may differ in some way from the original, I don't think that the length will be different. Of course, that assumes that there even is a supercession. The tubes sell for about 20 bucks, GM list, so this shouldn't be an expensive piece, either.

If you try the above, let us know how it all turns out. Feedback is important on a discussion board and it's too often forgotten.

[Harmon C.]

Re: Addendum

Marty
I would have thought someone with a 74 would have measured his dipstick for you but few who post here own 74's I guess. Try a post on Corvette Forum in the C-3 section as they have lots of posters with 74's and you may get a few answers before you buy a new dipstick.
Lyle

[Martin N.]

Re: Addendum

Joe & Lyle,

I will follow both of your suggestions. For $7.00 it'll be worth getting a new "clean" dipstick. I'll also post the question on the "corvette form". When I do get some answers I'll post my finding here. I could not agree with you more Joe, feed back and posted results are important to this community.
I hope to see more mid to late 70's related posts in the future, after all, "The more the meerier".

Thank-you both....Marty

[Joe L.]

Re: Addendum

Marty-----

Also, you might check the blade of the old dipstick for a part number. SOMETIMES, there will be a part number to be found. Not as often as there should be, but sometimes. If there is a part number, I could probably get a lot more definitive information on it. The number might even be a derivative of the complete part number, so if you can find any numbers, at all, that might be useful (unless it's only a single digit).