Anybody here has any experience with jess 4l80 transmissions ?
https://www.jegs.com/i/JEGS-Performa...60327/10002/-1

I have a '75 with the stock engine ( I have plans for a 406 in a couple of years) but want an OD. I already have a compushift computer for the trans and came across these from jets, seems not to crazy prize wise but I was wondering if anybody had experience with these.

I live in Europe and need to get the thing shipped to me so need something reliable.

Thanks

 

Thats,a big trans will it fit? I put in the 7004r. Same as 4L60 and there was not much room to spare. Those trans are good to the 500 plus horsepower range. Jegs is a reputable supplier


tci37100.....700r4 rated for 725hp. From jegs

 

I read of a couple of people making the swap and although tight, it fits.

 

Do more research on the 700r4 4l60, it may be everything you need. It was for me. It's also the trans in the c5s

 

Whether a 4l80 will fit or not depends on the car. My 80 had plenty of room around the 700R4 but my 75 Vert doesn't. The servo hits the tunnel on the passenger side and the trans is just tight everywhere. I would definitely have to cut the tunnel up to fit a 4l80 in the 75. No 2 of these cars are the same.

Mike

 

On my 77 I had 3/8 clearance around the yoke u joint it was really tight. I used all engineered linkage kits and cross member

 

The 4L60s have bad reputation for reliability under power, but they were refined and constantly upgraded in the aftermarket and during the GM switch to the 4L65e; most of the good rebuilds have been brought up to at least 4L65e specs -the 700r4/4l60e/4l65e cases will fit better, have less parasitic losses, and have a lower 1st gear for more fun off-the-line (you can actually negotiate Monster Transmission down on price). -I made the decision 2 summers ago to go with a proper rebuild 4L60/65e; the prospects of having to cut a hole in the tunnel put me off of the 4L80e option, personally. Obviously, the 4L80es are known to be bulletproof if you've got a high hp / torque motor, though...

Going with a computer-controlled, overdrive trans with a lockup TC, I'm sure will be nice with Belgian gas prices, either way. ;-)


Adam

 

I don't think my 4L60e was very far off from that on my 79. When I got it home, the yoke would actually hit the tunnel if I accelerated hard around a left-hand turn (the shop that installed it didn't install it correctly, though) -the fan would hit the top of the shroud when I slammed on the brakes, too. Took a stack of 3 washers to get it right. -I went with the bowtie overdrives cross member for 700r4 / 4L60 / 4L65e conversions; it's fantastic and lets the exhaust run below, instead of through the cross member and saves a decent bit of weight, too.


Adam

 

bow tie over drive engineered parts for the 700r4



shift detent


how tight it is


shortened drive shaft



oh yeah some under dash time



pressure test

 

drilling out detent





TC unlock/lock relay

 

4L60e conversion process is mostly the same, except no vacuum hookup to the trans, no detent cable, and you need the computer and wiring harness, a TPS sensor (if you don't already have one via an EFI conversion), and you need a conversion box for the tach or have it swapped to digital.

The RPM sensor just clamps over the distributor wire.
You need to calibrate the TPS sensor with a volt /ohm meter.
You need to run the computer touch screen through a setup wizard -enter rear gear, tire height, and modify the shift points, if desired.
If you go with the speedometer cable conversion box, you have to mark out 1 mile on a road and go through a calibration procedure with it, unfortunately, you have to reach under and push a button while driving out the mile and a passenger probably won't be able to reach it.

If you want you can wire in a toggle switch for "dyno mode" that will lock the TC in third and 4th full time when turned on. You can also wire in a toggle switch for "performance mode vs. ecomode" and set different shift points and firmness for performance mode. (I wired both but I screwed up something on the dyno mode switch as it doesn't work currently...)

You can go nuts and wire in paddle shifters, too; obviously completely unnecessary.

;-)

Adam

 

Hmm might look into the 4l60e way again, thanks for all the advice

 

I bit the bullet and ordered the Monster 4L80 E. I bought the custom built unit capable of over 1,000 hp., with the custom lock up converter. Putting the BPE 632 in my 68. Motor dynoed 840 hp on the first pull. Hoping for about 860 tuned. Did not want to chance it for the 750 hp unit.
Tall deck block plus 4L80- in for some long nights and curse words. Building a set of 2 1/8” SS headers also. No turning back now!!!
O

 

If a TH400 fit/came in your car year then a 4L80e should also fit. They are about the same case size wise except the 4L80e has a longer extension of the smaller part of the case on the tailshaft end.

Sure the 4L65e came in the C5's, but they are also cursed at by many C5 owners with extra power.

If you are willing to spend the time setting it up to shift how you want then you will love the electronic transmission.