Opinions on the 4L80E Transmission vs TH400
Good afternoon, I was considering a late '80s MH when it occurred to me that I could get an OD if I opted for an early '90s unit on a P30. The searching of done so far indicates that the gradually...
Forum Discussion
The TH400 and 4L80 are among the most reliable Chevy trans ever made and probably have equal durability all else being equal. Of course the TH400 is simpler which is cheaper to rebuild and doesn't require computers. The 4L80 has OD and is slightly more efficient even in direct, but requires computer control and has more expensive parts. Of the two, the 4L80 has more possible failure points. Either trans should serve very well if in an OEM situation (good engine and final gearing match.)
If you have two RV's you are comparing, one with the 4L80 and one with the TH400, and both are stock, I would find something else to base the decision on.
You are looking at late 80's early 90's rigs, they probably aren't really going to have the HP to be in OD too much anyway - especially at 60 MPH. MPG difference at 60 MPH will probably be very small if any. Any savings would be lost at trans rebuild time. If it were my RV I would lean TH400 based on that - all else being equal. If it were my DD pickup, I would go 4L80 all the way. Just my opinion.
If you have two RV's you are comparing, one with the 4L80 and one with the TH400, and both are stock, I would find something else to base the decision on.
You are looking at late 80's early 90's rigs, they probably aren't really going to have the HP to be in OD too much anyway - especially at 60 MPH. MPG difference at 60 MPH will probably be very small if any. Any savings would be lost at trans rebuild time. If it were my RV I would lean TH400 based on that - all else being equal. If it were my DD pickup, I would go 4L80 all the way. Just my opinion.
