My calcs say you will be turning 2500rpm at 75mph with 5.29s with the torque converter locked up, should be fine. It will be very spirited around town 
v8 swap guys - t case questions (1 Viewer)
- Thread starter jabhb
- Start date
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I've got 4.88, 37's and at 70 mph ( I do drive that speed frequently) the tach reads 21-22k rpm.
Like Georg says though, run what ya got.
I almost feel like for the hwy driving, a bit taller diff gears might be better, but on the rocks.... It does AMAZING w/ those gears and the doubler.
I consistently get Around 14 MPG. Not too bad for a built rig.
Like Georg says though, run what ya got.
I almost feel like for the hwy driving, a bit taller diff gears might be better, but on the rocks.... It does AMAZING w/ those gears and the doubler.
I consistently get Around 14 MPG. Not too bad for a built rig.
alia176
SILVER Star
You're running a V8 in a 5speed manual FJ40, no? Not sure if a doubler is needed in the 80 with auto trans. The TC does a decent job of torque multiplication if he's running 5.29s and a V8.
No.
I have the 5.3 to a 4l60e.
The auto does do a decent job, but not that great. The added control, gearing options and engine brake is priceless in many situations.
Is it absolutely necessary??? No. Is it nice to have... HELL YEAH!!
Just another option.
- Thread starter
- #25
Chicago, with that doubler, how is the gear play?
I'm looking at keeping mine daily drivable.
I'm looking at keeping mine daily drivable.
Skrewball
TLCA#18502
without changing the gas tank in the 80 you will have fitment issues if you stuff a 4l60/4l80, a 203, and then the transfer case.
if you do the split case, you could put the 4:1 gears in it. I don't know their reputation, but its an option.
if you do the split case, you could put the 4:1 gears in it. I don't know their reputation, but its an option.
orangefj45
Supporting Vendor
My 80 has had the Vortec engine and 4L60e transmission withthe split case in it for 90k miles. Been working great.
I also had the prototype 4:1 gear set in the same cruiser for 3 months before AA released them. I "tested" the gears and wasn't kind to them including a trip to pismo ( yeah, that was fun ). We pulled the entire 4:1 case back out after 3 months and put the original case and adapter back in. The low gear set showed no signs of wear. I wouldn't hesitate running them in my rig. I've also installed a few sets in customer's cruisers with no issues to date.
For a DD, I wouldn't run the 203GRB. there's no need for it and the added gear slop and shifter just complicate things. Plus you're dealing with a lot more possible leakage issues.
Just my two cents worth ......
Georg
I also had the prototype 4:1 gear set in the same cruiser for 3 months before AA released them. I "tested" the gears and wasn't kind to them including a trip to pismo ( yeah, that was fun ). We pulled the entire 4:1 case back out after 3 months and put the original case and adapter back in. The low gear set showed no signs of wear. I wouldn't hesitate running them in my rig. I've also installed a few sets in customer's cruisers with no issues to date.
For a DD, I wouldn't run the 203GRB. there's no need for it and the added gear slop and shifter just complicate things. Plus you're dealing with a lot more possible leakage issues.
Just my two cents worth ......
Georg
alia176
SILVER Star
George,
I wasn't aware of the "4:1" gear set from AA. Is this something new? I have their 3:1 gear set from Marks Adapters.
I am curious, is there a huge difference between a "split case" and an 80 Tcase (HF2AV) other than the fact that the older split case has to be split apart in order to divorce it from the transmission. Would the 3:1 gear set be interchangeable between a split case and the modern HF2AV Tcase? Even though my Tcase is part time, the thought of a "true" part time Tcase sounds more attractive to me.
Do you have any pics/details of your V8 swap on a thread somewhere?
I haven't had any real issues w/ it so far, but I didn't realize it was for a dd rig.
The others are right. If its not a crawler toy, there's no need to mess w/ a doubler set up. It's a LOT of work to make it all happen and work well within the rig.
I DO really love the low gearing though!!
Here is my build thread. https://forum.ih8mud.com/80-series-tech/403256-another-texas-ls1-swap.html
HTH
alia176
SILVER Star
