Whats my trannie?

[warbird]

Not too sure about my title up top there but here goes............
Can anyone tell me what transmisson is in my 1994 Astro EXT VIN# 1GNDM19W3RB201***
I can give you the last three if it helps? Also, It sometimes feels like there is a gear missing although since fitting a new distributor & the engine is now producing the power it should, It does seem much smoother! I keep hearing about 'lock up' in 4th too??
Can anyone help?
Cheers
Geoff

[astrozam]

If its still the original, then it will be a 4L60E

[warbird]

Hi, Wow! that was quick!! I presume that the -E means that its electronic? There does not seem to be any 'Lock Up' in 4th gear, It almost feels like there are 'sub gears' in the system! I'm just truing to find out as much as I can about my Astro as Its such a fantastic van!.
Cheers
Geoff
In very wet Bristol, UK!

[astrozam]

The E does indeed stand for electronic...

Here is a small list of common ailments...http://www.s-10crewcab.com/og1/modinfo/ ... 4l60e.html
And a link to an online parts store for the 4L60E http://www.makcotransmissionparts.com/4L60E-4L65E.html

[warbird]

Thanks for that info. Should my gearbox 'lock' in 4th gear? as If I take my foot off the gas the revs drop down which I would not expect if the system was 'locked'
Cheers
Geoff

[astrozam]

Are you getting any trouble codes set?

Do you drive with your tranny in D ( 3rd ) or in OD ( 4th ) ?

When I am driving my van with the gear selector in D ( as when I'm driving up a hill ) the van will stay in 3rd and pull nicely when I crest the hill the van will increase speed ( if I keep my foot on the gas the same ) but will not go up into 4th and the rpms will continue to get much higher until I manually shift the gear selector into OD.
Now, If I were to drive that same hill with the gear selector in OD the van would pull the hill in 3rd and when I crested the hill the van would speed up and then go into 4th ( the rpms would then drop, indicating I'm now locked in 4th gear ) This is how the tranny should behave.

I'm not sure if I've helped or hindered you with my above explanation, but I thought I'd throw it in there just in case.

[warbird]

Hi, I drive in 4th OD unless I'm towing then I stay out of OD, I had a look under my Astro today at the gearbox & I see no electronic bits hanging off the box, the only electrical bit is on the tailshaft of the box, I think that is for either the speedo or reversing light switch, or both so maybe I have the earlier non electronic box! I suppose there's less to go wrong if that is the case! Can anyone tell me what box that would be?
Cheers
Geoff

[Smiliesafari]

All of the electronics are inside the trans. With the exception of the VSS (vehicle speed sensor). That's the piece you see on the tailshaft. Signals from the VSS control the speedo and antilock brake system. The switching for the other electronics are on the side of the trans where the shifter connects and another plug that goes straight down toward the pan. Unless the trans has been changed, and I doubt that because it is computer controled, you have a 4L60E.

[warbird]

Thats one of the things I looked for, there is no quadrant where the shift shaft goes into the trans casing which I have seen on the later boxes. there are no other leads that I can see coming from or going to the gearbox, did the vans up to say, 1993 have a non computer gearbox?
Thanks for your help so far.
Geoff

[Smiliesafari]

It is posible that someone has installed a 700R4. Look to the rear of the shift shaft for a small four wire connector or the spot in the case where it should be. That is the only electronics in a 700R4 and it controls the torque converter lockup. It will be on top of the pan rail. 1993 was the first year of the 4L60E.

[warbird]

Ah! Just had a look at the box again & on the r/h side looking forwards there is a heat shield bolted to the side of the box & behind that there are plugs & wires! the tailshaft casting has 8679554-1 cast into it, I can't find any other ident markings, maybe they are under the heat shield which I might take off later to se what is there. at no time (as far as I can make out) does the transmission 'lock up' as in 4th O/D the revs will drop right back to almost idle if I take my foor off the gas!
Cheers
Geoff

[LiftedAWDAstro]

The trans should lock up in OD. Does your cruise control work? There is a switch on the brake pedal that unlocks the TCC. I think it is tied in with the cruise control but not sure.

[warbird]

Thats a good point! no, the cruise controls not working! Any idea what I need to check? I've looked around the C/C plug & vac pipes but I can't find any leaks or broken pipes.
Cheers
Geoff

[LiftedAWDAstro]

Check the switches on the brake pedal under the dash. There should be 2 switches. One is for the brake lights and the other is for the cruise and TCC.

[warbird]

Cheers, I'll have a look in the morning. I had a word with the vans previous owner tonight & he said that someone had done some work with the brakelight system, I wonder if they have disturbed something!!