How to 4L60E to 4L80E trans swap

[farmtruc]

Quick question for you guys with the 60E to 80E swap on a ccsb. Is the crossmember mod necessary on these too or is it just on reg cab and ext cabs?

It's necessary on all the crossmembers. The 80e is longer, therefore you need to extend the xmember.

[2boosted]

[armymech69]

Thanks, No one makes a crosmember for this swap or is it just big bucks so everyone does their own welding?

[2boosted]

#10C. Crossmember for the 4L60E to 4L80E transmission conversion, 2000 up Tahoe and some others. This custom made crossmember moves the transmission mount to the correct position for the 4WD Tahoe 4L60E to 4L80E conversion. Works with the #3XX deep cast aluminum pan that holds 3 3/4 extra quarts of fluid. Cost $350.00. On some trucks the crossmember will slide to the rear. This price includes a $160.00 core charge, return your old crossmember in good undamaged condition for a refund.

#10C2. Crossmember for the 4L60E to 4L80E transmission conversion, 2000 up Tahoe and some others. This custom made crossmember moves the transmission mount to the correct position for the 4WD Tahoe 4L60E to 4L80E conversion. Must be used with a late model type pan. Cost $330.00. On some trucks the crossmember will slide to the rear. This price includes a $160.00 core charge, return your old crossmember in good undamaged condition for a refund.

#10D. Crossmember for the 4L60E to 4L80E transmission conversion, 2007 up Tahoe (NEW BODY STYLE) and some others. This custom made crossmember moves the transmission mount to the correct position for the 4WD Tahoe 4L60E to 4L80E conversion. Works with the #3XX deep cast aluminum pan that holds 3 3/4 extra quarts of fluid. This crossmember isn't the same as #10C. Cost $330.00


http://www.transmissioncenter.net/4L...4L80E_Swap.htm

choose your poison !

[383STROKER]

Hey guys. I'm a newbe here but lets not let that keep us from getting down to the business at hand. Doing a 60 to 80 swap in a 1995 GMC Yukon. Before we start I'd like to say this is an awesome write up on it. Thank you for taking the time to share it.

OK, here we go. As above we're doing a 1991 4L80E swap into a 1995 4L60E GMC Yukon. The 80 came out of a 1991 Chevy van with a 5.7. The 1995 Yukon we're putting it in has what's left of a 4L60E behind a 500+hp 383 Stroker. Hence the need for an 80. The 80 we have was recently rebuilt having less than 5000 miles on it. The 383 in the Yukon has a EFI/TPI system with a FAST EZ-EFI tuner. Due to that system we can't run any electronics to the trans. No problem. We're going to install a manual shift kit into the 80 before we install it. So, with all the electronics set aside, (other than the speedometer in which we'll get into in a few minutes) we still ave a few issues we're not sure what to do about.
We've gone through this and several other write ups but can't find the answers to a few questions we have. With that said, lets start with shifter linkage. The 91 van had the old steel rod down the steering column linkage on it. It of course connected to the trans with yet another rod. You know the type. I'm also gonna assume you know the 95 Yukon has the cable style shift linkage. What can we do to swap the old rod linkage to the cable linkage? Is it as simple as unbolting the old rod arm off the trans and installing the newer cable arm in its place? Are they compatible? Next of course is the cable mounting bracket. Will the 60 bracket bolt up to the 80 trans? Basically, what do we need to do to make it work. If we need to fab something, no problem.
The second part of that issue is the neutral safety switch. First tell me this; where does the instrument clusters gear indicator lights get their signals from? If the signals come from the neutral safety switch, we're gonna have to figure out a way to mount it to the 80 trans. Just one problem. The shifter rod coming out of the 80 trans is too short for the switch to slide on to. Will the shift rod in the 60 trans interchange with the rod in the 80? If it will, we'll just make a bracket to hold the switch in place. (there's no mounting bosses on the 80 for the switch)

Now for that speedo issue. As you know the 60 has a sensor in the tail housing and the 80 has two in the case. I don't think I need to explain where I'm going with this so what do we need to do to make the speedo work?

We know we have to get the dive shaft shortened. Knowing that I just need to confirm that a TH400 and a 4L80 use the same yoke.

Next is the flex plate. Do we have to have a flex plate for an 80? What about a spacer plate? While we're here and depending on the flex plate answer, can we use the stock 5.7/4L60 starter?

I'm gonna stop here ......... for now. I'm sure we'll have more questions as we go along.

Thanks in advance for any and all help. We'd appreciate it.
Robert & Darryl

[RedHeartbeat]

Use the tail housing speedo hookup. Th400/80e plate and yoke are needed. No need to shorten the shaft. Xmember slides back to where you need it. Reuse existing holes or drill new ones. I used the gear PRNDL switch from my 60e on the 80e, shift arm, too. As for the shift linkage rod, replace it with a later model rod so that it is longer.

[383STROKER]

Use the tail housing speedo hookup. Th400/80e plate and yoke are needed. No need to shorten the shaft. Xmember slides back to where you need it. Reuse existing holes or drill new ones. I used the gear PRNDL switch from my 60e on the 80e, shift arm, too. As for the shift linkage rod, replace it with a later model rod so that it is longer.

OK, I'm a little confused on some of that. First, what tail housing speedo hookup? An 80 doesn't have one in the tail housing. Second, I thought an 80 was longer than a 60. How can you use the same length drive shaft behind a longer trans? Third, what year models have a long enough shift rod to accomidate the PRND321 switch?

Thanks for the help. However I'd appreciate it if you or somebody would address the questions you overlooked.

Thanks again.

[2boosted]

With that said, lets start with shifter linkage. The 91 van had the old steel rod down the steering column linkage on it. It of course connected to the trans with yet another rod. You know the type. I'm also gonna assume you know the 95 Yukon has the cable style shift linkage. What can we do to swap the old rod linkage to the cable linkage? Is it as simple as unbolting the old rod arm off the trans and installing the newer cable arm in its place? Are they compatible? Next of course is the cable mounting bracket. Will the 60 bracket bolt up to the 80 trans? Basically, what do we need to do to make it work. If we need to fab something, no problem.

The cable will work, and also the linkage. For holding the cable you will have to purchase or fab a bracket. The one that bolts to the pan is more likely to work in your application.

you can find it at http://www.transmissioncenter.net/4L80E.htm

The second part of that issue is the neutral safety switch. First tell me this; where does the instrument clusters gear indicator lights get their signals from? If the signals come from the neutral safety switch, we're gonna have to figure out a way to mount it to the 80 trans. Just one problem. The shifter rod coming out of the 80 trans is too short for the switch to slide on to. Will the shift rod in the 60 trans interchange with the rod in the 80? If it will, we'll just make a bracket to hold the switch in place. (there's no mounting bosses on the 80 for the switch)

Now this part is tricky......
You can use the same neutral switch from the 4L60e so you don't have to change connectors.
You will have to change the shifter rod, for the longer version from the new ones. 4L60E rod wont fit.

also available at PATC
Now here comes the tricky part, since your transmission have no mounting holes for the Neutral Switch, you will have to fab something that hold it to the exact place. This is a must for you, because you are going manual, so P and 1 position must be perfect calibrated.

Now for that speedo issue. As you know the 60 has a sensor in the tail housing and the 80 has two in the case. I don't think I need to explain where I'm going with this so what do we need to do to make the speedo work?
We know we have to get the dive shaft shortened. Knowing that I just need to confirm that a TH400 and a 4L80 use the same yoke.

Per Redheartbeat instructions. You will have to change the tail housing. (PATC)
If you change the yoke for a short one, you wont have to do anything to the Drive shaft. And sometimes, you don't have to change anything at all.

Next is the flex plate. Do we have to have a flex plate for an 80? What about a spacer plate? While we're here and depending on the flex plate answer, can we use the stock 5.7/4L60 starter?

Since your engine is a stocker, most likely you will need a double bolt flex-plate with weight, no spacer needed. Your Starter will work great.

Hope this helps !

[383STROKER]

Yes, it helps considerably. Thank you very much. Between the two of you, it sounds so simple even a caveman could do it. Now lets see if we can. LOL!!!

Summery;
Use the 60 shift arm and buy/fab a cable bracket.
Get the longer shift rod and fab a bracket to hold the n/safety switch in proper adjustment.
Speedo ????? Still a little confused. First, I saw where PATC offers a housing for a speedo cable but not one for a speedo sensor. Second, even if they have a housing with provisions for a sensor, the output shaft doesn't have a pickup for the sensor to read. Instead of replacing the housing, we found that we could use the rear speedo sensor in the 80 and recalibrate the drac/vssb. Instead of explaining it, see here; http://www.tbichips.com/drac/
Get a short TH400/4L80 drive shaft yoke. (no shortening of the shaft required)
Get a 5.7 4L80 flex plate. (GM 350 C.I. V8 (5.7L) External Balance Weight Flexplate) No spacer needed.
Strarter OK.

I'm sure I've overlooked some things but this should get us started. Any additional tips, advise, suggestions, do's, don'ts or warnings would be greatly appreciated. In fact, we encourage them.

Thanks again guys.

[RedHeartbeat]

I like to buy the long slip yoke and cut it to fit. Assemble it on the driveshaft, slide it all the way in, measure how much to cut off and cut off one more additional inch for suspension travel.