What transmission is in a 89 chieftain? - oil seal leak

[Odss91b]

What type of transmission is in the 89 chieftain. I have a leak and think it's the seal and need to buy one.

[M & J]

Probably a 400 HD

[cncsparky]

Most likely a TH475, more commonly referred to as TH400.  Output shaft seal is larger than standard TH400's.  I posted numbers in my P30 thread.

http://www.classicwinnebagos.com/forum/index.php/topic,9139.msg53438.html#msg53438

[Lefty]

If it does not have overdrive, it will be a TH400/TH475.. if it has overdrive it will be a 4L60.. easist way to tell is look at the gear indicator on the dash. If it has two D's, one with a circle around it and the other without, it's an overdrive transmission (4L60)  If there is just one D, it's a TH400/TH475.

[Hahn007]

If it is an overdrive transmission, wouldn't it be a 4L80E instead of the 4L60E ? 
4L60E seems like way too light duty for a motor home......

[cncsparky]

Correct it would be a 4L80E if overdrive, 454 engine.  I believe first year for those was 90 or 91, however.

[circleD]

4L60E is for Chevy half ton trucks with OD and its electric.
4L80E is the Chevy 3/4-1 ton with OD and is electric.
Electric meaning it needs a computer and wires.

[Odss91b]

Fixed the leak turns out it was the trans cooler lines. Replaced both and we are back in business!